diff --git a/cmd/serve.go b/cmd/serve.go
index 0cfc1cbc..9712f94f 100644
--- a/cmd/serve.go
+++ b/cmd/serve.go
@@ -52,6 +52,7 @@ var flagsServe = append(
 	altsrc.NewStringSliceFlag(&cli.StringSliceFlag{Name: "auth-users", Aliases: []string{"auth_users"}, EnvVars: []string{"NTFY_AUTH_USERS"}, Usage: "pre-provisioned declarative users"}),
 	altsrc.NewStringSliceFlag(&cli.StringSliceFlag{Name: "auth-access", Aliases: []string{"auth_access"}, EnvVars: []string{"NTFY_AUTH_ACCESS"}, Usage: "pre-provisioned declarative access control entries"}),
 	altsrc.NewStringSliceFlag(&cli.StringSliceFlag{Name: "auth-tokens", Aliases: []string{"auth_tokens"}, EnvVars: []string{"NTFY_AUTH_TOKENS"}, Usage: "pre-provisioned declarative access tokens"}),
+	altsrc.NewBoolFlag(&cli.BoolFlag{Name: "auth-access-cache", Aliases: []string{"auth_access_cache"}, EnvVars: []string{"NTFY_AUTH_ACCESS_CACHE"}, Value: user.DefaultAccessCacheEnabled, Usage: "enables the in-memory ACL cache (high-volume servers only)"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-cache-dir", Aliases: []string{"attachment_cache_dir"}, EnvVars: []string{"NTFY_ATTACHMENT_CACHE_DIR"}, Usage: "cache directory for attached files, or S3 URL (s3://ACCESS_KEY:SECRET_KEY@BUCKET[/PREFIX]?region=REGION[&endpoint=ENDPOINT])"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-total-size-limit", Aliases: []string{"attachment_total_size_limit", "A"}, EnvVars: []string{"NTFY_ATTACHMENT_TOTAL_SIZE_LIMIT"}, Value: util.FormatSize(server.DefaultAttachmentTotalSizeLimit), Usage: "limit of the on-disk attachment cache"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-file-size-limit", Aliases: []string{"attachment_file_size_limit", "Y"}, EnvVars: []string{"NTFY_ATTACHMENT_FILE_SIZE_LIMIT"}, Value: util.FormatSize(server.DefaultAttachmentFileSizeLimit), Usage: "per-file attachment size limit (e.g. 300k, 2M, 100M)"}),
@@ -168,6 +169,7 @@ func execServe(c *cli.Context) error {
 	authUsersRaw := c.StringSlice("auth-users")
 	authAccessRaw := c.StringSlice("auth-access")
 	authTokensRaw := c.StringSlice("auth-tokens")
+	authAccessCacheEnabled := c.Bool("auth-access-cache")
 	attachmentCacheDir := c.String("attachment-cache-dir")
 	attachmentTotalSizeLimitStr := c.String("attachment-total-size-limit")
 	attachmentFileSizeLimitStr := c.String("attachment-file-size-limit")
@@ -468,6 +470,7 @@ func execServe(c *cli.Context) error {
 	conf.AuthUsers = authUsers
 	conf.AuthAccess = authAccess
 	conf.AuthTokens = authTokens
+	conf.AuthAccessCacheEnabled = authAccessCacheEnabled
 	conf.AttachmentCacheDir = attachmentCacheDir
 	conf.AttachmentTotalSizeLimit = attachmentTotalSizeLimit
 	conf.AttachmentFileSizeLimit = attachmentFileSizeLimit
diff --git a/cmd/user.go b/cmd/user.go
index cd6cf795..2e5af5f4 100644
--- a/cmd/user.go
+++ b/cmd/user.go
@@ -378,6 +378,7 @@ func createUserManager(c *cli.Context) (*user.Manager, error) {
 		ProvisionEnabled:    false, // Hack: Do not re-provision users on manager initialization
 		BcryptCost:          user.DefaultUserPasswordBcryptCost,
 		QueueWriterInterval: user.DefaultUserStatsQueueWriterInterval,
+		AccessCacheEnabled:  false, // Do not cache for CLI commands
 	}
 	if databaseURL != "" {
 		host, dbErr := pg.Open(databaseURL)
diff --git a/cmd/user_test.go b/cmd/user_test.go
index ed6f5de4..a6250b72 100644
--- a/cmd/user_test.go
+++ b/cmd/user_test.go
@@ -1,14 +1,15 @@
 package cmd
 
 import (
+	"os"
+	"path/filepath"
+	"testing"
+
 	"github.com/stretchr/testify/require"
 	"github.com/urfave/cli/v2"
 	"heckel.io/ntfy/v2/server"
 	"heckel.io/ntfy/v2/test"
 	"heckel.io/ntfy/v2/user"
-	"os"
-	"path/filepath"
-	"testing"
 )
 
 func TestCLI_User_Add(t *testing.T) {
@@ -128,6 +129,7 @@ func newTestServerWithAuth(t *testing.T) (s *server.Server, conf *server.Config,
 	conf.File = configFile
 	conf.AuthFile = filepath.Join(t.TempDir(), "user.db")
 	conf.AuthDefault = user.PermissionDenyAll
+	conf.AuthAccessCacheEnabled = false
 	s, port = test.StartServerWithConfig(t, conf)
 	return
 }
diff --git a/docs/config.md b/docs/config.md
index c934143a..bc241a4f 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -2284,6 +2284,7 @@ variable before running the `ntfy` command (e.g. `export NTFY_LISTEN_HTTP=:80`).
 | `cache-batch-timeout`                      | `NTFY_CACHE_BATCH_TIMEOUT`                      | *duration*                                          | 0s                | Timeout for batched async writes to the message cache (if zero, writes are synchronous)                                                                                                                                                 |
 | `auth-file`                                | `NTFY_AUTH_FILE`                                | *filename*                                          | -                 | Auth database file used for access control (SQLite). If set, enables authentication and access control. Not required if `database-url` is set. See [access control](#access-control).                                                   |
 | `auth-default-access`                      | `NTFY_AUTH_DEFAULT_ACCESS`                      | `read-write`, `read-only`, `write-only`, `deny-all` | `read-write`      | Default permissions if no matching entries in the auth database are found. Default is `read-write`.                                                                                                                                     |
+| `auth-access-cache`                        | `NTFY_AUTH_ACCESS_CACHE`                        | *bool*                                              | false             | Enables an in-memory ACL cache so authorization checks no longer hit the database. Only worth enabling on high-volume servers.                                                                                                          |
 | `behind-proxy`                             | `NTFY_BEHIND_PROXY`                             | *bool*                                              | false             | If set, use forwarded header (e.g. X-Forwarded-For, X-Client-IP) to determine visitor IP address (for rate limiting)                                                                                                                    |
 | `proxy-forwarded-header`                   | `NTFY_PROXY_FORWARDED_HEADER`                   | *string*                                            | `X-Forwarded-For` | Use specified header to determine visitor IP address (for rate limiting)                                                                                                                                                                |
 | `proxy-trusted-hosts`                      | `NTFY_PROXY_TRUSTED_HOSTS`                      | *comma-separated host/IP/CIDR list*                 | -                 | Comma-separated list of trusted IP addresses, hosts, or CIDRs to remove from forwarded header                                                                                                                                           |
@@ -2295,7 +2296,7 @@ variable before running the `ntfy` command (e.g. `export NTFY_LISTEN_HTTP=:80`).
 | `smtp-sender-user`                         | `NTFY_SMTP_SENDER_USER`                         | *string*                                            | -                 | SMTP user; only used if e-mail sending is enabled                                                                                                                                                                                       |
 | `smtp-sender-pass`                         | `NTFY_SMTP_SENDER_PASS`                         | *string*                                            | -                 | SMTP password; only used if e-mail sending is enabled                                                                                                                                                                                   |
 | `smtp-sender-from`                         | `NTFY_SMTP_SENDER_FROM`                         | *e-mail address*                                    | -                 | SMTP sender e-mail address; only used if e-mail sending is enabled                                                                                                                                                                      |
-| `smtp-sender-verify`                       | `NTFY_SMTP_SENDER_VERIFY`                       | *bool*                                              | `false`           | If true, require verified email addresses for email notifications; anonymous email sending is disabled                                                                                                                                   |
+| `smtp-sender-verify`                       | `NTFY_SMTP_SENDER_VERIFY`                       | *bool*                                              | `false`           | If true, require verified email addresses for email notifications; anonymous email sending is disabled                                                                                                                                  |
 | `smtp-server-listen`                       | `NTFY_SMTP_SERVER_LISTEN`                       | `[ip]:port`                                         | -                 | Defines the IP address and port the SMTP server will listen on, e.g. `:25` or `1.2.3.4:25`                                                                                                                                              |
 | `smtp-server-domain`                       | `NTFY_SMTP_SERVER_DOMAIN`                       | *domain name*                                       | -                 | SMTP server e-mail domain, e.g. `ntfy.sh`                                                                                                                                                                                               |
 | `smtp-server-addr-prefix`                  | `NTFY_SMTP_SERVER_ADDR_PREFIX`                  | *string*                                            | -                 | Optional prefix for the e-mail addresses to prevent spam, e.g. `ntfy-`                                                                                                                                                                  |
@@ -2392,6 +2393,7 @@ OPTIONS:
    --auth-file value, --auth_file value, -H value                                                                         auth database file used for access control [$NTFY_AUTH_FILE]
    --auth-startup-queries value, --auth_startup_queries value                                                             queries run when the auth database is initialized [$NTFY_AUTH_STARTUP_QUERIES]
    --auth-default-access value, --auth_default_access value, -p value                                                     default permissions if no matching entries in the auth database are found (default: "read-write") [$NTFY_AUTH_DEFAULT_ACCESS]
+   --auth-access-cache, --auth_access_cache                                                                                enables the in-memory ACL cache (high-volume servers only) (default: false) [$NTFY_AUTH_ACCESS_CACHE]
    --attachment-cache-dir value, --attachment_cache_dir value                                                             cache directory for attached files, or S3 URL (s3://ACCESS_KEY:SECRET_KEY@BUCKET[/PREFIX]?region=REGION[&endpoint=ENDPOINT][&disable_http2=true]) [$NTFY_ATTACHMENT_CACHE_DIR]
    --attachment-total-size-limit value, --attachment_total_size_limit value, -A value                                     limit of the on-disk attachment cache (default: "5G") [$NTFY_ATTACHMENT_TOTAL_SIZE_LIMIT]
    --attachment-file-size-limit value, --attachment_file_size_limit value, -Y value                                       per-file attachment size limit (e.g. 300k, 2M, 100M) (default: "15M") [$NTFY_ATTACHMENT_FILE_SIZE_LIMIT]
diff --git a/docs/releases.md b/docs/releases.md
index df18add5..2853f25d 100644
--- a/docs/releases.md
+++ b/docs/releases.md
@@ -1926,6 +1926,10 @@ and the [ntfy Android app](https://github.com/binwiederhier/ntfy-android/release
 
 ### ntfy server v2.24.0 (UNRELEASED)
 
+**Features:**
+
+* Add opt-in in-memory ACL cache (`auth-access-cache`) that serves topic authorization without a database round-trip; off by default, intended for high-volume servers
+
 **Bug fixes + maintenance:**
 
 * Extend account token automatically from the PWA service worker, so installed PWAs don't get logged out ([#1669](https://github.com/binwiederhier/ntfy/pull/1669), [#1203](https://github.com/binwiederhier/ntfy/issues/1203), [#1533](https://github.com/binwiederhier/ntfy/issues/1533), thanks to [@nihalgonsalves](https://github.com/nihalgonsalves) for the contribution)
diff --git a/server/config.go b/server/config.go
index 1cfed3fc..b7dadddf 100644
--- a/server/config.go
+++ b/server/config.go
@@ -116,6 +116,8 @@ type Config struct {
 	AuthTokens                           map[string][]*user.Token
 	AuthBcryptCost                       int
 	AuthStatsQueueWriterInterval         time.Duration
+	AuthAccessCacheEnabled               bool          // Enables the in-memory ACL cache (high volume servers only)
+	AuthAccessCacheReloadInterval        time.Duration // Reload interval for access cache, relevant for ACL writes from CLI
 	AttachmentCacheDir                   string
 	AttachmentTotalSizeLimit             int64
 	AttachmentFileSizeLimit              int64
@@ -223,6 +225,8 @@ func NewConfig() *Config {
 		AuthDefault:                          user.PermissionReadWrite,
 		AuthBcryptCost:                       user.DefaultUserPasswordBcryptCost,
 		AuthStatsQueueWriterInterval:         user.DefaultUserStatsQueueWriterInterval,
+		AuthAccessCacheEnabled:               user.DefaultAccessCacheEnabled,
+		AuthAccessCacheReloadInterval:        user.DefaultAccessCacheReloadInterval,
 		AttachmentCacheDir:                   "",
 		AttachmentTotalSizeLimit:             DefaultAttachmentTotalSizeLimit,
 		AttachmentFileSizeLimit:              DefaultAttachmentFileSizeLimit,
diff --git a/server/server.go b/server/server.go
index 7ca0b4e7..c380bd26 100644
--- a/server/server.go
+++ b/server/server.go
@@ -247,16 +247,18 @@ func New(conf *Config) (*Server, error) {
 	var userManager *user.Manager
 	if conf.AuthFile != "" || pool != nil {
 		authConfig := &user.Config{
-			Filename:            conf.AuthFile,
-			DatabaseURL:         conf.DatabaseURL,
-			StartupQueries:      conf.AuthStartupQueries,
-			DefaultAccess:       conf.AuthDefault,
-			ProvisionEnabled:    true, // Enable provisioning of users and access
-			Users:               conf.AuthUsers,
-			Access:              conf.AuthAccess,
-			Tokens:              conf.AuthTokens,
-			BcryptCost:          conf.AuthBcryptCost,
-			QueueWriterInterval: conf.AuthStatsQueueWriterInterval,
+			Filename:                  conf.AuthFile,
+			DatabaseURL:               conf.DatabaseURL,
+			StartupQueries:            conf.AuthStartupQueries,
+			DefaultAccess:             conf.AuthDefault,
+			ProvisionEnabled:          true, // Enable provisioning of users and access
+			Users:                     conf.AuthUsers,
+			Access:                    conf.AuthAccess,
+			Tokens:                    conf.AuthTokens,
+			BcryptCost:                conf.AuthBcryptCost,
+			QueueWriterInterval:       conf.AuthStatsQueueWriterInterval,
+			AccessCacheEnabled:        conf.AuthAccessCacheEnabled,
+			AccessCacheReloadInterval: conf.AuthAccessCacheReloadInterval,
 		}
 		if pool != nil {
 			userManager, err = user.NewPostgresManager(pool, authConfig)
diff --git a/server/server.yml b/server/server.yml
index 08161dc2..ee23dd8b 100644
--- a/server/server.yml
+++ b/server/server.yml
@@ -116,6 +116,8 @@
 # - auth-tokens is a list of access tokens that are automatically created when the server starts.
 #   Each entry is in the format "<username>:<token>[:<label>]", e.g. "phil:tk_1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef:My token".
 #   Use 'ntfy token generate' to generate a new access token.
+# - auth-access-cache enables an in-memory snapshot of the access control table that authorizes every
+#   request without a database round-trip.
 #
 # Debian/RPM package users:
 #   Use /var/lib/ntfy/user.db as user database to avoid permission issues. The package
@@ -131,6 +133,7 @@
 # auth-users:
 # auth-access:
 # auth-tokens:
+# auth-access-cache: false
 
 # If set, the X-Forwarded-For header (or whatever is configured in proxy-forwarded-header) is used to determine
 # the visitor IP address instead of the remote address of the connection.
diff --git a/user/access_cache.go b/user/access_cache.go
new file mode 100644
index 00000000..f4029f89
--- /dev/null
+++ b/user/access_cache.go
@@ -0,0 +1,252 @@
+package user
+
+import (
+	"regexp"
+	"strings"
+	"sync"
+	"time"
+
+	"heckel.io/ntfy/v2/db"
+	"heckel.io/ntfy/v2/log"
+)
+
+// accessCache is an in-memory index over the entire user_access table.
+//
+// exact[username][escapedTopic] returns the matching entry in O(1) for the common
+// case where the requested topic appears verbatim in some rule. The key is the
+// stored form of the topic (i.e. with \_ escapes), so Lookup escapes incoming
+// topics through escapeUnderscore before probing.
+//
+// pattern[username] is the linear-scan list of %-bearing rules for that user.
+// Walked per request; trivially small in practice. Wildcards are NOT u_everyone-
+// only -- any user can create them.
+type accessCache struct {
+	exact   map[string]map[string]aclEntry
+	pattern map[string][]aclEntry
+	mu      sync.RWMutex // Protect exact and pattern
+}
+
+// aclEntry mirrors one user_access row. length feeds better()'s "longer
+// pattern wins" tie-break; the stored topic/pattern string itself is not kept
+// on the entry (the exact map already keys on it; surfacing wildcard "topics"
+// like "up%" alongside real ones would invite misuse). pattern is the
+// compiled regex form of the LIKE pattern; nil for exact entries.
+type aclEntry struct {
+	length  int
+	pattern *regexp.Regexp
+	read    bool
+	write   bool
+}
+
+func newAccessCache() *accessCache {
+	return &accessCache{
+		exact:   make(map[string]map[string]aclEntry),
+		pattern: make(map[string][]aclEntry),
+	}
+}
+
+// Lookup returns the effective (read, write, found) permission for the given
+// (username, topic), preserving the priority ordering of the original SQL query:
+//  1. specific user beats Everyone
+//  2. longer pattern beats shorter (more specific wins)
+//  3. write beats read at equal length (write is "stronger")
+func (c *accessCache) Lookup(username, topic string) (read, write, found bool) {
+	escapedTopic := escapeUnderscore(topic)
+	c.mu.RLock()
+	if username != Everyone {
+		if entry, found := c.lookupNoLock(username, topic, escapedTopic); found {
+			c.mu.RUnlock()
+			maybeLogACLDecision(username, username, topic, entry.read, entry.write)
+			return entry.read, entry.write, true
+		}
+	}
+	if entry, found := c.lookupNoLock(Everyone, topic, escapedTopic); found {
+		c.mu.RUnlock()
+		maybeLogACLDecision(username, Everyone, topic, entry.read, entry.write)
+		return entry.read, entry.write, true
+	}
+	c.mu.RUnlock()
+	maybeLogACLDecision(username, "", topic, false, false)
+	return false, false, false
+}
+
+// Reload scans (user_name, topic, read, write) rows and merges them into the
+// cache. With no usernames the cache is replaced wholesale; otherwise the
+// query is invoked with those usernames as positional args and only the
+// listed users' slices are touched (a username absent from the result drops
+// them from both maps). Runs against the primary so a reload after a
+// mutation sees the just-written rows.
+func (c *accessCache) Reload(d *db.DB, query string, usernames ...string) error {
+	started := time.Now()
+	scope := "full"
+	if len(usernames) > 0 {
+		scope = "users=" + strings.Join(usernames, ",")
+	}
+	args := make([]any, len(usernames))
+	for i, u := range usernames {
+		args[i] = u
+	}
+	// Query the database for all ACL entries
+	rows, err := d.Query(query, args...)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+	exacts := make(map[string]map[string]aclEntry)
+	patterns := make(map[string][]aclEntry)
+	updatedEntries := 0
+	for rows.Next() {
+		var username, escapedTopic string
+		var read, write bool
+		if err := rows.Scan(&username, &escapedTopic, &read, &write); err != nil {
+			return err
+		}
+		entry, hasWildcard, err := toACLEntry(escapedTopic, read, write)
+		if err != nil {
+			return err
+		}
+		if hasWildcard {
+			patterns[username] = append(patterns[username], entry)
+		} else {
+			if exacts[username] == nil {
+				exacts[username] = make(map[string]aclEntry)
+			}
+			exacts[username][escapedTopic] = entry
+		}
+		updatedEntries++
+	}
+	if err := rows.Err(); err != nil {
+		return err
+	}
+	// Replace or update the internal maps
+	c.mu.Lock()
+	if len(usernames) == 0 {
+		c.exact = exacts
+		c.pattern = patterns
+	} else {
+		for _, u := range usernames {
+			if e, ok := exacts[u]; ok {
+				c.exact[u] = e
+			} else {
+				delete(c.exact, u)
+			}
+			if p, ok := patterns[u]; ok {
+				c.pattern[u] = p
+			} else {
+				delete(c.pattern, u)
+			}
+		}
+	}
+	c.mu.Unlock()
+	log.Tag(tag).
+		Field("reload_scope", scope).
+		Field("updated_entries", updatedEntries).
+		Field("duration_ms", time.Since(started).Milliseconds()).
+		Debug("Reloaded ACL cache")
+	return nil
+}
+
+// lookupNoLock returns the highest-priority entry for a single user. When
+// more than one of that user's rules matches the requested topic, the winner
+// is chosen by:
+//
+//  1. longer stored pattern beats shorter (a more specific rule wins over a
+//     more general one)
+//  2. at equal length, write beats read (a stronger permission wins the tie)
+//
+// Exact and wildcard rules are ranked together under the same criteria, so
+// an exact "foo" (length 3) beats a wildcard "f%" (length 2), but a wildcard
+// "foo%" (length 4) beats an exact "foo" (length 3).
+func (c *accessCache) lookupNoLock(username, topic, escapedTopic string) (*aclEntry, bool) {
+	var best aclEntry
+	var found bool
+	if exact, exists := c.exact[username]; exists {
+		if entry, exists := exact[escapedTopic]; exists {
+			best, found = entry, true
+		}
+	}
+	for _, pattern := range c.pattern[username] {
+		if !pattern.pattern.MatchString(topic) {
+			continue
+		} else if !found || better(pattern, best) {
+			best, found = pattern, true
+		}
+	}
+	return &best, found
+}
+
+// toACLEntry builds an aclEntry from one user_access row's values. The
+// isWildcard return tells the caller which storage slot the entry belongs in:
+// the per-user wildcard slice if true, the per-user exact map if false.
+// Wildcards have their LIKE pattern pre-compiled into entry.pattern; exact
+// entries leave entry.pattern nil.
+func toACLEntry(escapedTopic string, read, write bool) (entry aclEntry, hasWildcard bool, err error) {
+	entry = aclEntry{
+		length: len(escapedTopic),
+		read:   read,
+		write:  write,
+	}
+	if !strings.Contains(escapedTopic, "%") {
+		return entry, false, nil
+	}
+	pattern, err := compileLikeToRegex(escapedTopic)
+	if err != nil {
+		return entry, true, err
+	}
+	entry.pattern = pattern
+	return entry, true, nil
+}
+
+// better implements the (length DESC, write DESC) tie-break used by the original
+// query's ORDER BY for entries owned by the same user.
+func better(a, b aclEntry) bool {
+	if a.length != b.length {
+		return a.length > b.length
+	} else if a.write != b.write {
+		return a.write
+	}
+	return false
+}
+
+// compileLikeToRegex converts a stored ntfy LIKE pattern into an equivalent Go
+// regexp. In ntfy's stored form, % is the only wildcard (translated from *) and
+// \_ is a literal underscore; no other backslashes occur. Topics themselves are
+// restricted to [A-Za-z0-9_-] (see AllowedTopic), so neither % nor stray
+// backslashes appear in user-supplied input.
+func compileLikeToRegex(pattern string) (*regexp.Regexp, error) {
+	var sb strings.Builder
+	sb.WriteString("^")
+	i := 0
+	for i < len(pattern) {
+		switch {
+		case pattern[i] == '\\' && i+1 < len(pattern) && pattern[i+1] == '_':
+			sb.WriteString(regexp.QuoteMeta("_"))
+			i += 2
+		case pattern[i] == '%':
+			sb.WriteString(".*")
+			i++
+		default:
+			sb.WriteString(regexp.QuoteMeta(string(pattern[i])))
+			i++
+		}
+	}
+	sb.WriteString("$")
+	return regexp.Compile(sb.String())
+}
+
+// maybeLogACLDecision logs an ACL lookup result
+func maybeLogACLDecision(requestUser, matchedUser, topic string, read, write bool) {
+	ev := log.Tag(tag).
+		Field("user_name", requestUser).
+		Field("topic", topic).
+		Field("read", read).
+		Field("write", write)
+	if !ev.IsTrace() {
+		return
+	}
+	if matchedUser == "" {
+		ev.Trace("ACL no match")
+		return
+	}
+	ev.Field("matched_user", matchedUser).Trace("ACL match")
+}
diff --git a/user/access_cache_test.go b/user/access_cache_test.go
new file mode 100644
index 00000000..17fd2c2c
--- /dev/null
+++ b/user/access_cache_test.go
@@ -0,0 +1,312 @@
+package user
+
+import (
+	"regexp"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// Cache-only unit tests. Integration with the Manager (loading from the DB,
+// reload-after-mutation, end-to-end Authorize behavior) is covered by the
+// existing TestStoreAuthorizeTopicAccess* tests in manager_test.go via
+// forEachStoreBackend.
+
+func TestCompileLikeToRegex_Exact(t *testing.T) {
+	r := mustCompileLikeToRegex(t, "foo")
+	require.True(t, r.MatchString("foo"))
+	require.False(t, r.MatchString("foox"))
+	require.False(t, r.MatchString("xfoo"))
+}
+
+func TestCompileLikeToRegex_TrailingPercent(t *testing.T) {
+	r := mustCompileLikeToRegex(t, "up%")
+	require.True(t, r.MatchString("up"))
+	require.True(t, r.MatchString("up123"))
+	require.False(t, r.MatchString("xup"))
+}
+
+func TestCompileLikeToRegex_LeadingAndEmbeddedPercent(t *testing.T) {
+	r := mustCompileLikeToRegex(t, "%test%")
+	require.True(t, r.MatchString("test"))
+	require.True(t, r.MatchString("mytest"))
+	require.True(t, r.MatchString("testxxx"))
+	require.True(t, r.MatchString("xtestx"))
+	require.False(t, r.MatchString("nope"))
+}
+
+func TestCompileLikeToRegex_EscapedUnderscore(t *testing.T) {
+	// "my\_topic" is the stored form of a literal "my_topic" -- the underscore
+	// must match itself, NOT act as a SQL one-character wildcard.
+	r := mustCompileLikeToRegex(t, `my\_topic`)
+	require.True(t, r.MatchString("my_topic"))
+	require.False(t, r.MatchString("myXtopic"))
+	require.False(t, r.MatchString("mytopic"))
+}
+
+func TestCompileLikeToRegex_EscapedUnderscoreAdjacentToPercent(t *testing.T) {
+	// "nz\_vip\_%" is the stored form of "nz_vip_*" -- literal "nz_vip_" prefix
+	// followed by any suffix.
+	r := mustCompileLikeToRegex(t, `nz\_vip\_%`)
+	require.True(t, r.MatchString("nz_vip_"))
+	require.True(t, r.MatchString("nz_vip_alpha"))
+	require.False(t, r.MatchString("nz_vipX"))
+	require.False(t, r.MatchString("nzvip_alpha"))
+}
+
+func TestCompileLikeToRegex_RegexMetaCharsInTopic(t *testing.T) {
+	// Topics in ntfy can include '-', which is benign, but make sure
+	// regex metacharacters in the pattern are escaped properly anyway.
+	r := mustCompileLikeToRegex(t, "foo-bar")
+	require.True(t, r.MatchString("foo-bar"))
+	require.False(t, r.MatchString("foo.bar")) // would match if '-' leaked into a character class
+}
+
+func TestACLCache_LookupBeforeReload(t *testing.T) {
+	// A freshly-constructed cache has empty exact and wildcards maps. The
+	// cache treats this as "no rule found", which the caller resolves via
+	// DefaultAccess.
+	c := newAccessCache()
+	read, write, found := c.Lookup("phil", "mytopic")
+	require.False(t, found)
+	require.False(t, read)
+	require.False(t, write)
+}
+
+func TestACLCache_ExactMatchHit(t *testing.T) {
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: "phil", topic: "mytopic", read: true, write: true},
+	})
+	read, write, found := c.Lookup("phil", "mytopic")
+	require.True(t, found)
+	require.True(t, read)
+	require.True(t, write)
+}
+
+func TestACLCache_ExactMatchMiss(t *testing.T) {
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: "phil", topic: "mytopic", read: true, write: true},
+	})
+	_, _, found := c.Lookup("phil", "othertopic")
+	require.False(t, found)
+}
+
+func TestACLCache_LiteralUnderscoreExactMatch(t *testing.T) {
+	// Stored as "my\_topic" (toSQLWildcard of "my_topic"). A literal underscore
+	// in the requested topic must match, while any other single char must not.
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: "phil", topic: `my\_topic`, read: true, write: false},
+	})
+	read, write, found := c.Lookup("phil", "my_topic")
+	require.True(t, found)
+	require.True(t, read)
+	require.False(t, write)
+
+	_, _, found = c.Lookup("phil", "myXtopic")
+	require.False(t, found)
+}
+
+func TestACLCache_WildcardMatch(t *testing.T) {
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: Everyone, topic: "up%", read: false, write: true},
+	})
+	read, write, found := c.Lookup("phil", "up42")
+	require.True(t, found)
+	require.False(t, read)
+	require.True(t, write)
+}
+
+func TestACLCache_SpecificUserBeatsEveryone(t *testing.T) {
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: Everyone, topic: "mytopic", read: true, write: false},
+		{user: "phil", topic: "mytopic", read: false, write: false}, // deny-all for phil
+	})
+	read, write, found := c.Lookup("phil", "mytopic")
+	require.True(t, found)
+	require.False(t, read)
+	require.False(t, write)
+}
+
+func TestACLCache_SpecificUserBeatsEveryoneEvenWhenShorter(t *testing.T) {
+	// The SQL's "user_name DESC" sort key takes precedence over LENGTH(topic).
+	// Concretely: a specific user with a shorter matching rule still wins over
+	// Everyone with a longer matching rule.
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: Everyone, topic: "foo", read: true, write: true}, // exact, length 3
+		{user: "phil", topic: "f%", read: false, write: false},  // wildcard, length 2, deny-all
+	})
+	read, write, found := c.Lookup("phil", "foo")
+	require.True(t, found)
+	require.False(t, read)
+	require.False(t, write)
+}
+
+func TestACLCache_SpecificUserBeatsEveryoneRegardlessOfWrite(t *testing.T) {
+	// Same-length rules but conflicting permissions across user boundary: the
+	// specific user always wins, even if its permission set is weaker (or
+	// stronger, in either direction).
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: Everyone, topic: "mytopic", read: true, write: true}, // wide-open
+		{user: "phil", topic: "mytopic", read: true, write: false},  // read-only for phil
+	})
+	read, write, found := c.Lookup("phil", "mytopic")
+	require.True(t, found)
+	require.True(t, read)
+	require.False(t, write)
+}
+
+func TestACLCache_AnonymousReadsEveryone(t *testing.T) {
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: Everyone, topic: "announcements", read: true, write: false},
+	})
+	read, write, found := c.Lookup(Everyone, "announcements")
+	require.True(t, found)
+	require.True(t, read)
+	require.False(t, write)
+}
+
+func TestACLCache_LongerPatternWinsForSameUser(t *testing.T) {
+	// Both rules belong to the same user (Everyone). The more specific (longer)
+	// "mytopic%" should beat the catch-all "%".
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: Everyone, topic: "%", read: true, write: false},
+		{user: Everyone, topic: "mytopic%", read: true, write: true},
+	})
+	read, write, found := c.Lookup(Everyone, "mytopicX")
+	require.True(t, found)
+	require.True(t, read)
+	require.True(t, write)
+}
+
+func TestACLCache_ExactBeatsShorterWildcardSameUser(t *testing.T) {
+	// Same user, two matching rules: exact "foo" (length 3) and wildcard "f%"
+	// (length 2). The longer one wins, which is the exact rule -- mirroring
+	// the SQL's "LENGTH(topic) DESC" tie-break. Crucially, the cache must seed
+	// "best" from the exact map probe before walking wildcards, otherwise a
+	// shorter wildcard could overwrite a longer exact.
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: "phil", topic: "foo", read: true, write: true},  // exact, length 3
+		{user: "phil", topic: "f%", read: false, write: false}, // wildcard, length 2, deny-all
+	})
+	read, write, found := c.Lookup("phil", "foo")
+	require.True(t, found)
+	require.True(t, read)
+	require.True(t, write)
+}
+
+func TestACLCache_LongerWildcardBeatsExactSameUser(t *testing.T) {
+	// Same user, two matching rules: exact "foo" (length 3) and wildcard "foo%"
+	// (length 4). The wildcard wins on length DESC. Exercises the "swap best
+	// to wildcard when better() returns true" path.
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: "phil", topic: "foo", read: false, write: false}, // exact, length 3, deny-all
+		{user: "phil", topic: "foo%", read: true, write: true},  // wildcard, length 4
+	})
+	read, write, found := c.Lookup("phil", "foo")
+	require.True(t, found)
+	require.True(t, read)
+	require.True(t, write)
+}
+
+func TestACLCache_WriteBeatsReadAtEqualLength(t *testing.T) {
+	// Two wildcard rules of identical length for the same user. The write rule
+	// should win the tie-break. The two-rows-with-same-topic shape is
+	// impossible via real upsert (pkey would conflict), so we inject the entries
+	// directly into the cache's wildcard slice.
+	c := newAccessCache()
+	c.mu.Lock()
+	c.exact = map[string]map[string]aclEntry{}
+	c.pattern = map[string][]aclEntry{
+		Everyone: {
+			{length: len("ab%"), read: true, write: false, pattern: mustCompileLikeToRegex(t, "ab%")},
+			{length: len("ab%"), read: false, write: true, pattern: mustCompileLikeToRegex(t, "ab%")},
+		},
+	}
+	c.mu.Unlock()
+	_, write, found := c.Lookup(Everyone, "abc")
+	require.True(t, found)
+	require.True(t, write)
+}
+
+func TestACLCache_ConcurrentLookupAndReload(t *testing.T) {
+	// Lock-based swap must be safe under concurrent reads. The race detector
+	// catches any unsafe shared mutation.
+	c := newAccessCache()
+	loadCache(t, c, []rawACLRow{
+		{user: Everyone, topic: "mytopic", read: true, write: true},
+	})
+
+	var stop atomic.Bool
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		for !stop.Load() {
+			_, _, _ = c.Lookup(Everyone, "mytopic")
+		}
+	}()
+	go func() {
+		defer wg.Done()
+		for i := 0; i < 100; i++ {
+			loadCache(t, c, []rawACLRow{
+				{user: Everyone, topic: "mytopic", read: i%2 == 0, write: i%2 == 1},
+			})
+		}
+		stop.Store(true)
+	}()
+	wg.Wait()
+}
+
+// rawACLRow models the rows that reload would Scan from the DB but avoids
+// actually opening a DB for these unit tests.
+type rawACLRow struct {
+	user  string
+	topic string
+	read  bool
+	write bool
+}
+
+// loadCache writes the given rows into the cache under its write lock,
+// preserving the same exact/wildcard partitioning that reload would produce.
+func loadCache(t *testing.T, c *accessCache, rows []rawACLRow) {
+	t.Helper()
+	exact := make(map[string]map[string]aclEntry)
+	wildcards := make(map[string][]aclEntry)
+	for _, r := range rows {
+		e := aclEntry{length: len(r.topic), read: r.read, write: r.write}
+		if strings.Contains(r.topic, "%") {
+			e.pattern = mustCompileLikeToRegex(t, r.topic)
+			wildcards[r.user] = append(wildcards[r.user], e)
+		} else {
+			if exact[r.user] == nil {
+				exact[r.user] = make(map[string]aclEntry)
+			}
+			exact[r.user][r.topic] = e
+		}
+	}
+	c.mu.Lock()
+	c.exact = exact
+	c.pattern = wildcards
+	c.mu.Unlock()
+}
+
+func mustCompileLikeToRegex(t *testing.T, pattern string) *regexp.Regexp {
+	t.Helper()
+	r, err := compileLikeToRegex(pattern)
+	require.NoError(t, err)
+	return r
+}
diff --git a/user/manager.go b/user/manager.go
index 303c7a49..b036df73 100644
--- a/user/manager.go
+++ b/user/manager.go
@@ -38,6 +38,8 @@ const (
 const (
 	DefaultUserStatsQueueWriterInterval = 33 * time.Second
 	DefaultUserPasswordBcryptCost       = 10
+	DefaultAccessCacheEnabled           = false
+	DefaultAccessCacheReloadInterval    = 87 * time.Second
 )
 
 var (
@@ -48,12 +50,14 @@ var (
 
 // Manager handles user authentication, authorization, and management
 type Manager struct {
-	config     *Config
-	db         *db.DB
-	queries    queries
-	statsQueue map[string]*Stats       // "Queue" to asynchronously write user stats to the database (UserID -> Stats)
-	tokenQueue map[string]*TokenUpdate // "Queue" to asynchronously write token access stats to the database (Token ID -> TokenUpdate)
-	mu         sync.Mutex
+	config      *Config
+	db          *db.DB
+	queries     queries
+	statsQueue  map[string]*Stats       // "Queue" to asynchronously write user stats to the database (UserID -> Stats)
+	tokenQueue  map[string]*TokenUpdate // "Queue" to asynchronously write token access stats to the database (Token ID -> TokenUpdate)
+	accessCache *accessCache            // In-memory snapshot of user_access; refreshed by maybeReloadAccessCache after every ACL mutation
+	quit        chan struct{}           // Closed by Close() to signal background goroutines to stop
+	mu          sync.Mutex
 }
 
 var _ Auther = (*Manager)(nil)
@@ -65,20 +69,65 @@ func newManager(d *db.DB, queries queries, config *Config) (*Manager, error) {
 	if config.QueueWriterInterval.Seconds() <= 0 {
 		config.QueueWriterInterval = DefaultUserStatsQueueWriterInterval
 	}
+	if config.AccessCacheReloadInterval <= 0 {
+		config.AccessCacheReloadInterval = DefaultAccessCacheReloadInterval
+	}
 	manager := &Manager{
 		config:     config,
 		db:         d,
 		statsQueue: make(map[string]*Stats),
 		tokenQueue: make(map[string]*TokenUpdate),
+		quit:       make(chan struct{}),
 		queries:    queries,
 	}
 	if err := manager.maybeProvisionUsersAccessAndTokens(); err != nil {
 		return nil, err
 	}
-	go manager.asyncQueueWriter(manager.config.QueueWriterInterval)
+	if config.AccessCacheEnabled {
+		manager.accessCache = newAccessCache()
+		if err := manager.maybeReloadAccessCache(); err != nil {
+			return nil, err
+		}
+		go manager.asyncAccessCacheReloadLoop(manager.config.AccessCacheReloadInterval)
+	}
+	go manager.asyncQueueWriteLoop(manager.config.QueueWriterInterval)
 	return manager, nil
 }
 
+// maybeReloadAccessCache refreshes the in-memory access cache from the
+// primary database. No-op when the cache is disabled. With no usernames it
+// does a full bulk reload; with one or more it refreshes only those users'
+// slices in a single DB round-trip via an IN clause.
+func (a *Manager) maybeReloadAccessCache(usernames ...string) error {
+	if a.accessCache == nil {
+		return nil
+	}
+	if len(usernames) == 0 {
+		return a.accessCache.Reload(a.db, a.queries.selectAccessCacheAll)
+	}
+	return a.accessCache.Reload(a.db, a.queries.selectAccessCacheUsers(len(usernames)), usernames...)
+}
+
+// asyncAccessCacheReloadLoop periodically bulk-reloads the access cache so that
+// writes made by other processes against the same database (most notably the
+// `ntfy access` CLI subcommand running while a server holds the cache) become
+// visible within the configured interval. This Manager's own mutations do
+// not depend on the poller -- they refresh affected users synchronously.
+func (a *Manager) asyncAccessCacheReloadLoop(interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-a.quit:
+			return
+		case <-ticker.C:
+			if err := a.maybeReloadAccessCache(); err != nil {
+				log.Tag(tag).Err(err).Warn("Reloading ACL cache failed")
+			}
+		}
+	}
+}
+
 // Authenticate checks username and password and returns a User if correct, and the user has not been
 // marked as deleted. The method returns in constant-ish time, regardless of whether the user exists or
 // the password is correct or incorrect.
@@ -151,9 +200,14 @@ func (a *Manager) RemoveUser(username string) error {
 	if err := a.CanChangeUser(username); err != nil {
 		return err
 	}
-	return db.ExecTx(a.db, func(tx *sql.Tx) error {
+	err := db.ExecTx(a.db, func(tx *sql.Tx) error {
 		return a.removeUserTx(tx, username)
 	})
+	if err != nil {
+		return err
+	}
+	// Reload user-specific parts of the access cache
+	return a.maybeReloadAccessCache(username, Everyone)
 }
 
 // removeUserTx deletes the user with the given username
@@ -174,7 +228,7 @@ func (a *Manager) MarkUserRemoved(user *User) error {
 	if !AllowedUsername(user.Name) {
 		return ErrInvalidArgument
 	}
-	return db.ExecTx(a.db, func(tx *sql.Tx) error {
+	err := db.ExecTx(a.db, func(tx *sql.Tx) error {
 		if err := a.resetUserAccessTx(tx, user.Name); err != nil {
 			return err
 		}
@@ -187,14 +241,27 @@ func (a *Manager) MarkUserRemoved(user *User) error {
 		}
 		return nil
 	})
+	if err != nil {
+		return err
+	}
+	// Reload user-specific parts of the access cache
+	return a.maybeReloadAccessCache(user.Name, Everyone)
 }
 
 // RemoveDeletedUsers deletes all users that have been marked deleted
 func (a *Manager) RemoveDeletedUsers() error {
-	if _, err := a.db.Exec(a.queries.deleteUsersMarked, time.Now().Unix()); err != nil {
+	res, err := a.db.Exec(a.queries.deleteUsersMarked, time.Now().Unix())
+	if err != nil {
 		return err
 	}
-	return nil
+	affected, err := res.RowsAffected()
+	if err != nil {
+		return err
+	} else if affected == 0 {
+		return nil
+	}
+	// Full cache reload, because we don't know which users were affected.
+	return a.maybeReloadAccessCache()
 }
 
 // ChangePassword changes a user's password
@@ -225,9 +292,14 @@ func (a *Manager) ChangeRole(username string, role Role) error {
 	if err := a.CanChangeUser(username); err != nil {
 		return err
 	}
-	return db.ExecTx(a.db, func(tx *sql.Tx) error {
+	err := db.ExecTx(a.db, func(tx *sql.Tx) error {
 		return a.changeRoleTx(tx, username, role)
 	})
+	if err != nil {
+		return err
+	}
+	// Full cache reload: Role changes are extremely rare.
+	return a.maybeReloadAccessCache()
 }
 
 // changeRoleTx changes a user's role
@@ -351,14 +423,20 @@ func (a *Manager) EnqueueUserStats(userID string, stats *Stats) {
 	a.statsQueue[userID] = stats
 }
 
-func (a *Manager) asyncQueueWriter(interval time.Duration) {
+func (a *Manager) asyncQueueWriteLoop(interval time.Duration) {
 	ticker := time.NewTicker(interval)
-	for range ticker.C {
-		if err := a.writeUserStatsQueue(); err != nil {
-			log.Tag(tag).Err(err).Warn("Writing user stats queue failed")
-		}
-		if err := a.writeTokenUpdateQueue(); err != nil {
-			log.Tag(tag).Err(err).Warn("Writing token update queue failed")
+	defer ticker.Stop()
+	for {
+		select {
+		case <-a.quit:
+			return
+		case <-ticker.C:
+			if err := a.writeUserStatsQueue(); err != nil {
+				log.Tag(tag).Err(err).Warn("Writing user stats queue failed")
+			}
+			if err := a.writeTokenUpdateQueue(); err != nil {
+				log.Tag(tag).Err(err).Warn("Writing token update queue failed")
+			}
 		}
 	}
 }
@@ -588,9 +666,14 @@ func (a *Manager) resolvePerms(base, perm Permission) error {
 // read/write access to a topic. The parameter topicPattern may include wildcards (*). The ACL entry
 // owner may either be a user (username), or the system (empty).
 func (a *Manager) AllowAccess(username string, topicPattern string, permission Permission) error {
-	return db.ExecTx(a.db, func(tx *sql.Tx) error {
+	err := db.ExecTx(a.db, func(tx *sql.Tx) error {
 		return a.allowAccessTx(tx, username, topicPattern, permission, false)
 	})
+	if err != nil {
+		return err
+	}
+	// Only this user's row set changed; refresh their slice only.
+	return a.maybeReloadAccessCache(username)
 }
 
 func (a *Manager) allowAccessTx(tx *sql.Tx, username string, topicPattern string, permission Permission, provisioned bool) error {
@@ -606,9 +689,20 @@ func (a *Manager) allowAccessTx(tx *sql.Tx, username string, topicPattern string
 // ResetAccess removes an access control list entry for a specific username/topic, or (if topic is
 // empty) for an entire user. The parameter topicPattern may include wildcards (*).
 func (a *Manager) ResetAccess(username string, topicPattern string) error {
-	return db.ExecTx(a.db, func(tx *sql.Tx) error {
+	err := db.ExecTx(a.db, func(tx *sql.Tx) error {
 		return a.resetAccessTx(tx, username, topicPattern)
 	})
+	if err != nil {
+		return err
+	}
+	// Empty username -> deleteAllAccess affected every user, bulk reload.
+	// Otherwise refresh the named user plus Everyone, since resetUserAccessTx
+	// and deleteTopicAccess both touch rows owned by the user (typically the
+	// Everyone row from their reservations).
+	if username == "" {
+		return a.maybeReloadAccessCache()
+	}
+	return a.maybeReloadAccessCache(username, Everyone)
 }
 
 func (a *Manager) resetAccessTx(tx *sql.Tx, username string, topicPattern string) error {
@@ -650,10 +744,20 @@ func (a *Manager) AllowReservation(username string, topic string) error {
 // authorizeTopicAccess returns the read/write permissions for the given username and topic.
 // The found return value indicates whether an ACL entry was found at all.
 //
-// - The query may return two rows (one for everyone, and one for the user), but prioritizes the user.
-// - Furthermore, the query prioritizes more specific permissions (longer!) over more generic ones, e.g. "test*" > "*"
-// - It also prioritizes write permissions over read permissions
+// Priority:
+//   - Specific user beats Everyone
+//   - Longer pattern beats shorter (a more specific rule beats a more general one,
+//     e.g. "test*" > "*")
+//   - Write beats read at equal length
+//
+// When AccessCacheEnabled is true (config), the lookup is served entirely from
+// the in-memory snapshot maintained by accessCache. Otherwise the original SQL
+// query is executed against the database on every call.
 func (a *Manager) authorizeTopicAccess(usernameOrEveryone, topic string) (read, write, found bool, err error) {
+	if a.accessCache != nil {
+		read, write, found = a.accessCache.Lookup(usernameOrEveryone, topic)
+		return read, write, found, nil
+	}
 	rows, err := a.db.ReadOnly().Query(a.queries.selectTopicPerms, Everyone, usernameOrEveryone, topic)
 	if err != nil {
 		return false, false, false, err
@@ -731,7 +835,7 @@ func (a *Manager) AddReservation(username string, topic string, everyone Permiss
 	if !AllowedUsername(username) || username == Everyone || !AllowedTopic(topic) {
 		return ErrInvalidArgument
 	}
-	return db.ExecTx(a.db, func(tx *sql.Tx) error {
+	err := db.ExecTx(a.db, func(tx *sql.Tx) error {
 		if limit > 0 {
 			hasReservation, err := a.hasReservationTx(tx, username, topic)
 			if err != nil {
@@ -755,6 +859,11 @@ func (a *Manager) AddReservation(username string, topic string, everyone Permiss
 		}
 		return nil
 	})
+	if err != nil {
+		return err
+	}
+	// Both user's and Everyone's rows changed.
+	return a.maybeReloadAccessCache(username, Everyone)
 }
 
 // RemoveReservations deletes the access control entries associated with the given username/topic,
@@ -769,7 +878,7 @@ func (a *Manager) RemoveReservations(username string, topics ...string) error {
 			return ErrInvalidArgument
 		}
 	}
-	return db.ExecTx(a.db, func(tx *sql.Tx) error {
+	err := db.ExecTx(a.db, func(tx *sql.Tx) error {
 		for _, topic := range topics {
 			if err := a.removeReservationAccessTx(tx, username, topic); err != nil {
 				return err
@@ -777,6 +886,12 @@ func (a *Manager) RemoveReservations(username string, topics ...string) error {
 		}
 		return nil
 	})
+	if err != nil {
+		return err
+	}
+	// Mirror the DB: rows for this user and any Everyone rows owned by this
+	// user are gone. Refresh both slices.
+	return a.maybeReloadAccessCache(username, Everyone)
 }
 
 // Reservations returns all user-owned topics, and the associated everyone-access
@@ -1515,8 +1630,14 @@ func (a *Manager) maybeProvisionTokens(tx *sql.Tx, provisionUsernames []string,
 	return nil
 }
 
-// Close closes the underlying database
+// Close stops background goroutines and closes the underlying database.
 func (a *Manager) Close() error {
+	select {
+	case <-a.quit:
+		// Already closed
+	default:
+		close(a.quit)
+	}
 	return a.db.Close()
 }
 
diff --git a/user/manager_postgres.go b/user/manager_postgres.go
index 02cffd84..0395baae 100644
--- a/user/manager_postgres.go
+++ b/user/manager_postgres.go
@@ -1,6 +1,9 @@
 package user
 
 import (
+	"fmt"
+	"strings"
+
 	"heckel.io/ntfy/v2/db"
 )
 
@@ -77,6 +80,11 @@ const (
 		WHERE (u.user_name = $1 OR u.user_name = $2) AND $3 LIKE a.topic ESCAPE '\'
 		ORDER BY u.user_name DESC, LENGTH(a.topic) DESC, CASE WHEN a.write THEN 1 ELSE 0 END DESC
 	`
+	postgresSelectAccessCacheAllQuery = `
+		SELECT u.user_name, a.topic, a.read, a.write
+		FROM user_access a
+		JOIN "user" u ON u.id = a.user_id
+	`
 	postgresSelectUserAllAccessQuery = `
 		SELECT user_id, topic, read, write, provisioned
 		FROM user_access
@@ -221,6 +229,21 @@ const (
 	`
 )
 
+// postgresSelectAccessCacheUsersQuery builds the per-users cache-load query
+// with a "$1, $2, ..." IN clause sized for n usernames.
+func postgresSelectAccessCacheUsersQuery(n int) string {
+	var sb strings.Builder
+	sb.WriteString(`SELECT u.user_name, a.topic, a.read, a.write FROM user_access a JOIN "user" u ON u.id = a.user_id WHERE u.user_name IN (`)
+	for i := 0; i < n; i++ {
+		if i > 0 {
+			sb.WriteString(",")
+		}
+		fmt.Fprintf(&sb, "$%d", i+1)
+	}
+	sb.WriteString(")")
+	return sb.String()
+}
+
 // NewPostgresManager creates a new Manager backed by a PostgreSQL database using an existing connection pool.
 var postgresQueries = queries{
 	selectUserByID:               postgresSelectUserByIDQuery,
@@ -245,6 +268,8 @@ var postgresQueries = queries{
 	deleteUsersMarked:            postgresDeleteUsersMarkedQuery,
 	deleteUsersProvisioned:       postgresDeleteUsersProvisionedQuery,
 	selectTopicPerms:             postgresSelectTopicPermsQuery,
+	selectAccessCacheAll:         postgresSelectAccessCacheAllQuery,
+	selectAccessCacheUsers:       postgresSelectAccessCacheUsersQuery,
 	selectUserAllAccess:          postgresSelectUserAllAccessQuery,
 	selectUserAccess:             postgresSelectUserAccessQuery,
 	selectUserReservations:       postgresSelectUserReservationsQuery,
diff --git a/user/manager_sqlite.go b/user/manager_sqlite.go
index 0f1a9227..18cb4028 100644
--- a/user/manager_sqlite.go
+++ b/user/manager_sqlite.go
@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"fmt"
 	"path/filepath"
+	"strings"
 
 	_ "github.com/mattn/go-sqlite3" // SQLite driver
 
@@ -83,6 +84,11 @@ const (
 		WHERE (u.user = ? OR u.user = ?) AND ? LIKE a.topic ESCAPE '\'
 		ORDER BY u.user DESC, LENGTH(a.topic) DESC, a.write DESC
 	`
+	sqliteSelectAccessCacheAllQuery = `
+		SELECT u.user, a.topic, a.read, a.write
+		FROM user_access a
+		JOIN user u ON u.id = a.user_id
+	`
 	sqliteSelectUserAllAccessQuery = `
 		SELECT user_id, topic, read, write, provisioned
 		FROM user_access
@@ -220,6 +226,21 @@ const (
 	`
 )
 
+// sqliteSelectAccessCacheUsersQuery builds the per-users cache-load query
+// with a "?, ?, ..." IN clause sized for n usernames.
+func sqliteSelectAccessCacheUsersQuery(n int) string {
+	var sb strings.Builder
+	sb.WriteString(`SELECT u.user, a.topic, a.read, a.write FROM user_access a JOIN user u ON u.id = a.user_id WHERE u.user IN (`)
+	for i := 0; i < n; i++ {
+		if i > 0 {
+			sb.WriteString(",")
+		}
+		sb.WriteString("?")
+	}
+	sb.WriteString(")")
+	return sb.String()
+}
+
 var sqliteQueries = queries{
 	selectUserByID:               sqliteSelectUserByIDQuery,
 	selectUserByName:             sqliteSelectUserByNameQuery,
@@ -243,6 +264,8 @@ var sqliteQueries = queries{
 	deleteUsersMarked:            sqliteDeleteUsersMarkedQuery,
 	deleteUsersProvisioned:       sqliteDeleteUsersProvisionedQuery,
 	selectTopicPerms:             sqliteSelectTopicPermsQuery,
+	selectAccessCacheAll:         sqliteSelectAccessCacheAllQuery,
+	selectAccessCacheUsers:       sqliteSelectAccessCacheUsersQuery,
 	selectUserAllAccess:          sqliteSelectUserAllAccessQuery,
 	selectUserAccess:             sqliteSelectUserAccessQuery,
 	selectUserReservations:       sqliteSelectUserReservationsQuery,
diff --git a/user/manager_test.go b/user/manager_test.go
index 3bdb15b2..5d6944f2 100644
--- a/user/manager_test.go
+++ b/user/manager_test.go
@@ -2169,6 +2169,148 @@ func TestStoreAuthorizeTopicAccessDenyAll(t *testing.T) {
 	})
 }
 
+// TestAuthorizeTopicAccess_CacheAndDirectDBAgree wires up two Managers on the
+// same backend storage -- one with AccessCacheEnabled=true (in-memory cache
+// path) and one with AccessCacheEnabled=false (direct SQL path) -- then runs
+// an identical battery of authorizeTopicAccess queries against both and
+// asserts byte-identical (read, write, found) responses for every query.
+// This protects the in-memory implementation from drifting away from the
+// SQL behavior it is meant to mirror.
+func TestAuthorizeTopicAccess_CacheAndDirectDBAgree(t *testing.T) {
+	forEachBackend(t, func(t *testing.T, newManager newManagerFunc) {
+		// Seed via a Manager with the cache enabled. Writes go to the shared
+		// backend; both Managers will see them after the writes commit.
+		writer := newManager(&Config{
+			DefaultAccess:      PermissionDenyAll,
+			BcryptCost:         bcrypt.MinCost,
+			AccessCacheEnabled: true,
+		})
+		t.Cleanup(func() { writer.Close() })
+
+		require.Nil(t, writer.AddUser("phil", "mypass", RoleAdmin, false))
+		require.Nil(t, writer.AddUser("ben", "mypass", RoleUser, false))
+		require.Nil(t, writer.AddUser("alice", "mypass", RoleUser, false))
+
+		// A mix that exercises every branch of the priority logic:
+		//   - exact and wildcard rules for the same user
+		//   - exact and wildcard rules under Everyone
+		//   - Everyone rules that are longer than the matching user rule
+		//   - literal underscores (stored as "\_")
+		//   - deny-all permissions
+		require.Nil(t, writer.AllowAccess("ben", "mytopic", PermissionReadWrite))
+		require.Nil(t, writer.AllowAccess("ben", "readme", PermissionRead))
+		require.Nil(t, writer.AllowAccess("ben", "writeme", PermissionWrite))
+		require.Nil(t, writer.AllowAccess("ben", "ben_topic", PermissionReadWrite))
+		require.Nil(t, writer.AllowAccess("ben", "mytopic*", PermissionRead))
+		require.Nil(t, writer.AllowAccess("alice", "alice_*", PermissionWrite))
+		require.Nil(t, writer.AllowAccess("alice", "secret", PermissionDenyAll))
+		require.Nil(t, writer.AllowAccess(Everyone, "announcements", PermissionRead))
+		require.Nil(t, writer.AllowAccess(Everyone, "up*", PermissionWrite))
+		require.Nil(t, writer.AllowAccess(Everyone, "mytopic", PermissionDenyAll))
+
+		// Build a reader Manager with the cache OFF, pointing at the same backend.
+		reader := newManager(&Config{
+			DefaultAccess:      PermissionDenyAll,
+			BcryptCost:         bcrypt.MinCost,
+			AccessCacheEnabled: false,
+		})
+		t.Cleanup(func() { reader.Close() })
+
+		// Probe matrix: every (user, topic) pair that exercises some branch.
+		cases := []struct {
+			user, topic string
+		}{
+			// Anonymous reads.
+			{Everyone, "announcements"},
+			{Everyone, "up42"},
+			{Everyone, "up"},
+			{Everyone, "downstream"},
+			{Everyone, "mytopic"},
+			{Everyone, "nope"},
+			// Specific user, only-user rules.
+			{"ben", "mytopic"},
+			{"ben", "readme"},
+			{"ben", "writeme"},
+			{"ben", "ben_topic"},
+			{"ben", "benXtopic"}, // underscore in rule means "X" must NOT match
+			// Specific user falls through to Everyone.
+			{"ben", "announcements"},
+			{"ben", "up5"},
+			{"alice", "announcements"},
+			// Wildcards with literal underscores.
+			{"alice", "alice_anything"},
+			{"alice", "alice_"},
+			{"alice", "aliceX"}, // does NOT match alice_*
+			// Exact-vs-wildcard overlap for the same user (ben has both
+			// "mytopic" exact and "mytopic*" wildcard).
+			{"ben", "mytopic"},   // exact wins on length
+			{"ben", "mytopicX"},  // only wildcard matches
+			{"ben", "mytopicYZ"}, // only wildcard matches
+			// Deny-all override.
+			{"alice", "secret"},
+			// No matching rule anywhere.
+			{"ben", "completely_unmatched"},
+			{"alice", "completely_unmatched"},
+			{Everyone, "completely_unmatched"},
+		}
+
+		// Sanity: the two Managers must agree on every probe.
+		for _, tc := range cases {
+			cRead, cWrite, cFound, cErr := writer.authorizeTopicAccess(tc.user, tc.topic)
+			dRead, dWrite, dFound, dErr := reader.authorizeTopicAccess(tc.user, tc.topic)
+			require.Nil(t, cErr, "cache path errored for (%s, %s)", tc.user, tc.topic)
+			require.Nil(t, dErr, "direct-DB path errored for (%s, %s)", tc.user, tc.topic)
+			require.Equal(t, dFound, cFound, "found mismatch for (%s, %s)", tc.user, tc.topic)
+			require.Equal(t, dRead, cRead, "read mismatch for (%s, %s)", tc.user, tc.topic)
+			require.Equal(t, dWrite, cWrite, "write mismatch for (%s, %s)", tc.user, tc.topic)
+		}
+	})
+}
+
+// TestAccessCacheReloadInterval_PicksUpExternalWrite proves that the
+// background reloader actually closes the cross-process coherence gap: a
+// write made through a *different* Manager on the same backend becomes
+// visible to a cache-enabled Manager within roughly one reload interval,
+// without that Manager being told about the write.
+func TestAccessCacheReloadInterval_PicksUpExternalWrite(t *testing.T) {
+	const interval = 25 * time.Millisecond
+	forEachBackend(t, func(t *testing.T, newManager newManagerFunc) {
+		// reader holds the cache and polls; writer plays the role of an
+		// out-of-band process (e.g. `ntfy access` CLI) writing to the same
+		// backend.
+		reader := newManager(&Config{
+			DefaultAccess:             PermissionDenyAll,
+			BcryptCost:                bcrypt.MinCost,
+			AccessCacheEnabled:        true,
+			AccessCacheReloadInterval: interval,
+		})
+		t.Cleanup(func() { reader.Close() })
+
+		writer := newManager(&Config{
+			DefaultAccess:      PermissionDenyAll,
+			BcryptCost:         bcrypt.MinCost,
+			AccessCacheEnabled: false,
+		})
+		t.Cleanup(func() { writer.Close() })
+
+		require.Nil(t, writer.AddUser("phil", "mypass", RoleUser, false))
+		// Sanity: before the write, the reader sees no rule for this topic.
+		_, _, found, err := reader.authorizeTopicAccess("phil", "via-poller")
+		require.Nil(t, err)
+		require.False(t, found)
+
+		// Write through the second Manager. reader's cache is unaware.
+		require.Nil(t, writer.AllowAccess("phil", "via-poller", PermissionReadWrite))
+
+		// Wait for the poller to catch up. The interval is 25ms; allow a
+		// generous multiple to keep this test from flaking on slow CI.
+		require.Eventually(t, func() bool {
+			read, write, found, err := reader.authorizeTopicAccess("phil", "via-poller")
+			return err == nil && found && read && write
+		}, 2*time.Second, 10*time.Millisecond, "reader's cache never observed the external write")
+	})
+}
+
 func TestStoreReservations(t *testing.T) {
 	forEachStoreBackend(t, func(t *testing.T, manager *Manager) {
 		require.Nil(t, manager.AddUser("phil", "mypass", RoleUser, false))
diff --git a/user/types.go b/user/types.go
index d0d40e33..c400e48f 100644
--- a/user/types.go
+++ b/user/types.go
@@ -245,16 +245,18 @@ const (
 
 // Config holds the configuration for the user Manager
 type Config struct {
-	Filename            string              // Database filename, e.g. "/var/lib/ntfy/user.db" (SQLite)
-	DatabaseURL         string              // Database connection string (PostgreSQL)
-	StartupQueries      string              // Queries to run on startup, e.g. to create initial users or tiers (SQLite only)
-	DefaultAccess       Permission          // Default permission if no ACL matches
-	ProvisionEnabled    bool                // Hack: Enable auto-provisioning of users and access grants, disabled for "ntfy user" commands
-	Users               []*User             // Predefined users to create on startup
-	Access              map[string][]*Grant // Predefined access grants to create on startup (username -> []*Grant)
-	Tokens              map[string][]*Token // Predefined users to create on startup (username -> []*Token)
-	QueueWriterInterval time.Duration       // Interval for the async queue writer to flush stats and token updates to the database
-	BcryptCost          int                 // Cost of generated passwords; lowering makes testing faster
+	Filename                  string              // Database filename, e.g. "/var/lib/ntfy/user.db" (SQLite)
+	DatabaseURL               string              // Database connection string (PostgreSQL)
+	StartupQueries            string              // Queries to run on startup, e.g. to create initial users or tiers (SQLite only)
+	DefaultAccess             Permission          // Default permission if no ACL matches
+	ProvisionEnabled          bool                // Hack: Enable auto-provisioning of users and access grants, disabled for "ntfy user" commands
+	Users                     []*User             // Predefined users to create on startup
+	Access                    map[string][]*Grant // Predefined access grants to create on startup (username -> []*Grant)
+	Tokens                    map[string][]*Token // Predefined users to create on startup (username -> []*Token)
+	QueueWriterInterval       time.Duration       // Interval for the async queue writer to flush stats and token updates to the database
+	BcryptCost                int                 // Cost of generated passwords; lowering makes testing faster
+	AccessCacheEnabled        bool                // Enables the in-memory ACL cache (high volume servers only)
+	AccessCacheReloadInterval time.Duration       // Reload interval for access cache, relevant for ACL writes from CLI
 }
 
 // Error constants used by the package
@@ -303,7 +305,9 @@ type queries struct {
 	deleteUsersProvisioned       string
 
 	// Access queries
-	selectTopicPerms            string
+	selectTopicPerms            string             // Direct-DB authorizeTopicAccess query; used when the in-memory cache is disabled
+	selectAccessCacheAll        string             // Bulk load: (user_name, topic, read, write) for the in-memory ACL cache
+	selectAccessCacheUsers      func(n int) string // Returns a per-users load query whose IN clause is sized for n usernames
 	selectUserAllAccess         string
 	selectUserAccess            string
 	selectUserReservations      string