diff --git a/lib/kalshi/rest.js b/lib/kalshi/rest.js
index 6681155..40460f6 100644
--- a/lib/kalshi/rest.js
+++ b/lib/kalshi/rest.js
@@ -1,20 +1,80 @@
 import { signRequest, KALSHI_API_BASE } from './auth.js';
 
-const SERIES_TICKER = 'KXBTC15M';
+const SERIES_TICKER = (process.env.KALSHI_SERIES_TICKER || 'KXBTC15M').trim().toUpperCase();
 const OPEN_EVENT_STATUSES = new Set(['open', 'active', 'initialized', 'trading']);
 const TRADABLE_EVENT_STATUSES = new Set(['open', 'active', 'trading']);
 
-async function kalshiFetch(method, path, body = null) {
-  const headers = signRequest(method, path);
-  const opts = { method, headers };
-  if (body) opts.body = JSON.stringify(body);
+const DEFAULT_HTTP_RETRIES = Math.max(0, Number(process.env.KALSHI_HTTP_RETRIES || 3));
+const BASE_BACKOFF_MS = Math.max(100, Number(process.env.KALSHI_HTTP_BACKOFF_MS || 350));
+
+const EVENTS_CACHE_TTL_MS = Math.max(1000, Number(process.env.KALSHI_EVENTS_CACHE_TTL_MS || 5000));
+const eventsCache = new Map(); // key -> { expiresAt, data }
+const inflightEvents = new Map(); // key -> Promise<events>
+
+const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
+
+function parseRetryAfterMs(value) {
+  if (!value) return null;
+
+  const asSeconds = Number(value);
+  if (Number.isFinite(asSeconds) && asSeconds >= 0) return asSeconds * 1000;
+
+  const asDate = new Date(value).getTime();
+  if (Number.isFinite(asDate)) return Math.max(0, asDate - Date.now());
+
+  return null;
+}
+
+function backoffMs(attempt) {
+  const exp = BASE_BACKOFF_MS * Math.pow(2, attempt);
+  const jitter = Math.floor(Math.random() * 200);
+  return exp + jitter;
+}
+
+async function kalshiFetch(method, path, body = null, opts = {}) {
+  const retries = Number.isFinite(opts.retries) ? opts.retries : DEFAULT_HTTP_RETRIES;
+  const payload = body == null ? null : JSON.stringify(body);
+
+  for (let attempt = 0; attempt <= retries; attempt++) {
+    const headers = signRequest(method, path);
+    const req = { method, headers };
+    if (payload) req.body = payload;
+
+    let res;
+    try {
+      res = await fetch(`${KALSHI_API_BASE}${path}`, req);
+    } catch (e) {
+      if (attempt < retries) {
+        await sleep(backoffMs(attempt));
+        continue;
+      }
+      throw new Error(`Kalshi API ${method} ${path} network error: ${e.message}`);
+    }
+
+    if (res.ok) {
+      if (res.status === 204) return {};
+      const text = await res.text();
+      if (!text) return {};
+      try {
+        return JSON.parse(text);
+      } catch {
+        return {};
+      }
+    }
 
-  const res = await fetch(`${KALSHI_API_BASE}${path}`, opts);
-  if (!res.ok) {
     const text = await res.text();
+    const retryable = res.status === 429 || (res.status >= 500 && res.status < 600);
+
+    if (retryable && attempt < retries) {
+      const retryAfter = parseRetryAfterMs(res.headers.get('retry-after'));
+      await sleep(retryAfter ?? backoffMs(attempt));
+      continue;
+    }
+
     throw new Error(`Kalshi API ${method} ${path} → ${res.status}: ${text}`);
   }
-  return res.json();
+
+  throw new Error(`Kalshi API ${method} ${path} failed after retries`);
 }
 
 function getTimeMs(value) {
@@ -46,11 +106,10 @@ function rankEvents(events = []) {
       const tradableLike = TRADABLE_EVENT_STATUSES.has(status);
       const notClearlyExpired = closeTs == null || closeTs > now - 60_000;
 
-      // Prefer near-future close times; heavily penalize stale/past
       const delta = closeTs == null ? Number.MAX_SAFE_INTEGER : closeTs - now;
       const closenessScore = delta < 0 ? Math.abs(delta) + 3_600_000 : delta;
 
-      return { event, openLike, tradableLike, notClearlyExpired, closenessScore, closeTs };
+      return { event, openLike, tradableLike, notClearlyExpired, closenessScore };
     })
     .filter((x) => x.openLike || x.notClearlyExpired)
     .sort((a, b) => {
@@ -62,34 +121,74 @@ function rankEvents(events = []) {
     .map((x) => x.event);
 }
 
+function getCachedEvents(key) {
+  const hit = eventsCache.get(key);
+  if (!hit) return null;
+  if (Date.now() > hit.expiresAt) {
+    eventsCache.delete(key);
+    return null;
+  }
+  return hit.data;
+}
+
+function setCachedEvents(key, events) {
+  eventsCache.set(key, {
+    expiresAt: Date.now() + EVENTS_CACHE_TTL_MS,
+    data: events
+  });
+}
+
 async function fetchEvents(series, query) {
-  const path = `/trade-api/v2/events?series_ticker=${encodeURIComponent(series)}&${query}`;
-  const data = await kalshiFetch('GET', path);
-  return Array.isArray(data.events) ? data.events : [];
+  const normalizedSeries = String(series || '').trim().toUpperCase();
+  const normalizedQuery = String(query || '').trim();
+  const key = `${normalizedSeries}|${normalizedQuery}`;
+
+  const cached = getCachedEvents(key);
+  if (cached) return cached;
+
+  const pending = inflightEvents.get(key);
+  if (pending) return pending;
+
+  const task = (async () => {
+    try {
+      const path = `/trade-api/v2/events?series_ticker=${encodeURIComponent(normalizedSeries)}&${normalizedQuery}`;
+      const data = await kalshiFetch('GET', path);
+      const events = Array.isArray(data.events) ? data.events : [];
+      setCachedEvents(key, events);
+      return events;
+    } finally {
+      inflightEvents.delete(key);
+    }
+  })();
+
+  inflightEvents.set(key, task);
+  return task;
 }
 
 /**
  * Return ranked candidate events for BTC 15m.
  */
 export async function getActiveBTCEvents(limit = 12) {
-  const seriesCandidates = [...new Set([SERIES_TICKER, SERIES_TICKER.toLowerCase()])];
+  const seriesCandidates = [SERIES_TICKER];
   const eventMap = new Map();
 
   for (const series of seriesCandidates) {
-    for (const query of [
-      'status=open&limit=10',
-      'status=active&limit=10',
-      'status=initialized&limit=10',
-      'limit=50'
-    ]) {
-      try {
-        const events = await fetchEvents(series, query);
-        for (const event of events) {
+    try {
+      // Use only known-good filter to avoid 400s from unsupported statuses.
+      const openEvents = await fetchEvents(series, 'status=open&limit=25');
+      for (const event of openEvents) {
+        if (event?.event_ticker) eventMap.set(event.event_ticker, event);
+      }
+
+      // Fallback if endpoint returns empty.
+      if (!openEvents.length) {
+        const fallbackEvents = await fetchEvents(series, 'limit=25');
+        for (const event of fallbackEvents) {
           if (event?.event_ticker) eventMap.set(event.event_ticker, event);
         }
-      } catch (e) {
-        console.error(`[Kalshi] Event fetch failed (${series}, ${query}):`, e.message);
       }
+    } catch (e) {
+      console.error(`[Kalshi] Event fetch failed (${series}):`, e.message);
     }
   }