diff --git a/explore/src/jetstream.js b/explore/src/jetstream.js
index eabf3e4..8cf42cf 100644
--- a/explore/src/jetstream.js
+++ b/explore/src/jetstream.js
@@ -19,6 +19,18 @@ function beaconValue(value) {
   return typeof value === 'string' && value.length > 0 ? value : null;
 }
 
+function enqueueRecordTask(recordTasks, key, task) {
+  const previous = recordTasks.get(key) ?? Promise.resolve();
+  const current = previous.catch(() => {}).then(task);
+  recordTasks.set(key, current);
+  void current.finally(() => {
+    if (recordTasks.get(key) === current) {
+      recordTasks.delete(key);
+    }
+  }).catch(() => {});
+  return current;
+}
+
 function incrementCapBeaconStatements(env, beacon) {
   return [
     env.DB.prepare(
@@ -262,6 +274,7 @@ export async function streamEvents(env, cursor) {
     let latestCursor = cursor || null;
     const newDids = new Set();
     const pending = new Set();
+    const recordTasks = new Map();
     const ws = new WebSocket(url.toString());
 
     const timeout = setTimeout(() => {
@@ -306,9 +319,13 @@ export async function streamEvents(env, cursor) {
         }
 
         if (commit.collection === CAP_COLLECTION) {
-          await processCapEvent(env, msg.did, commit);
+          await enqueueRecordTask(recordTasks, `${CAP_COLLECTION}:${msg.did}:${commit.rkey}`, () => (
+            processCapEvent(env, msg.did, commit)
+          ));
         } else if (commit.collection === VOUCH_COLLECTION) {
-          await processVouchEvent(env, msg.did, commit);
+          await enqueueRecordTask(recordTasks, `${VOUCH_COLLECTION}:${msg.did}:${commit.rkey}`, () => (
+            processVouchEvent(env, msg.did, commit)
+          ));
         } else if (commit.collection === SKILL_COLLECTION) {
           await processSkillEvent(env, msg.did, commit);
         }
diff --git a/test/explore-jetstream-race.test.js b/test/explore-jetstream-race.test.js
new file mode 100644
index 0000000..5807d7e
--- /dev/null
+++ b/test/explore-jetstream-race.test.js
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2026 sol pbc
+
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test';
+import { streamEvents } from '../explore/src/jetstream.js';
+
+const BEACON = 'vit:github.com/solpbc/vit';
+
+let originalWebSocket;
+let originalFetch;
+
+beforeEach(() => {
+  originalWebSocket = globalThis.WebSocket;
+  originalFetch = globalThis.fetch;
+  globalThis.fetch = async () => ({ ok: false });
+});
+
+afterEach(() => {
+  globalThis.WebSocket = originalWebSocket;
+  globalThis.fetch = originalFetch;
+});
+
+class FakeStatement {
+  constructor(db, sql, args = []) {
+    this.db = db;
+    this.sql = sql.replace(/\s+/g, ' ').trim();
+    this.args = args;
+  }
+
+  bind(...args) {
+    return new FakeStatement(this.db, this.sql, args);
+  }
+
+  async first() {
+    if (this.sql.startsWith('SELECT beacon FROM caps')) {
+      const [did, rkey] = this.args;
+      const row = this.db.caps.get(`${did}/${rkey}`) ?? null;
+      await new Promise(resolve => setTimeout(resolve, 0));
+      return row;
+    }
+
+    if (this.sql.startsWith('SELECT beacon FROM vouches')) {
+      const [did, rkey] = this.args;
+      const row = this.db.vouches.get(`${did}/${rkey}`) ?? null;
+      await new Promise(resolve => setTimeout(resolve, 0));
+      return row;
+    }
+
+    if (this.sql.startsWith('SELECT handle, fetched_at FROM handles')) {
+      return null;
+    }
+
+    throw new Error(`unsupported first: ${this.sql}`);
+  }
+
+  async run() {
+    if (this.sql.startsWith('INSERT INTO caps')) {
+      const [did, rkey, uri, cid, title, description, ref, beacon, kind, recordJson, createdAt] = this.args;
+      this.db.caps.set(`${did}/${rkey}`, {
+        did,
+        rkey,
+        uri,
+        cid,
+        title,
+        description,
+        ref,
+        beacon,
+        kind,
+        record_json: recordJson,
+        created_at: createdAt,
+      });
+      return { success: true };
+    }
+
+    if (this.sql.startsWith('INSERT INTO vouches')) {
+      const [did, rkey, uri, cid, capUri, ref, beacon, kind, recordJson, createdAt] = this.args;
+      this.db.vouches.set(`${did}/${rkey}`, {
+        did,
+        rkey,
+        uri,
+        cid,
+        cap_uri: capUri,
+        ref,
+        beacon,
+        kind,
+        record_json: recordJson,
+        created_at: createdAt,
+      });
+      return { success: true };
+    }
+
+    if (this.sql.startsWith('INSERT INTO beacons') && this.sql.includes('cap_count')) {
+      const [beacon] = this.args;
+      const row = this.db.beacons.get(beacon) ?? { name: beacon, cap_count: 0, vouch_count: 0 };
+      row.cap_count += 1;
+      this.db.beacons.set(beacon, row);
+      return { success: true };
+    }
+
+    if (this.sql.startsWith('INSERT INTO beacons') && this.sql.includes('vouch_count')) {
+      const [beacon] = this.args;
+      const row = this.db.beacons.get(beacon) ?? { name: beacon, cap_count: 0, vouch_count: 0 };
+      row.vouch_count += 1;
+      this.db.beacons.set(beacon, row);
+      return { success: true };
+    }
+
+    throw new Error(`unsupported run: ${this.sql}`);
+  }
+}
+
+class FakeD1 {
+  constructor() {
+    this.caps = new Map();
+    this.vouches = new Map();
+    this.beacons = new Map();
+  }
+
+  prepare(sql) {
+    return new FakeStatement(this, sql);
+  }
+
+  async batch(statements) {
+    for (const statement of statements) {
+      await statement.run();
+    }
+    return statements.map(() => ({ success: true }));
+  }
+}
+
+function installWebSocketReplay(messages) {
+  globalThis.WebSocket = class FakeWebSocket {
+    constructor() {
+      this.listeners = {};
+      setTimeout(() => {
+        for (const message of messages) {
+          this.listeners.message?.({ data: JSON.stringify(message) });
+        }
+        setTimeout(() => this.listeners.close?.({}), 0);
+      }, 0);
+    }
+
+    addEventListener(type, callback) {
+      this.listeners[type] = callback;
+    }
+
+    close() {
+      this.listeners.close?.({});
+    }
+  };
+}
+
+function capMessage() {
+  return {
+    kind: 'commit',
+    did: 'did:plc:race',
+    time_us: 1,
+    commit: {
+      operation: 'create',
+      collection: 'org.v-it.cap',
+      rkey: 'same-rkey',
+      cid: 'cap-cid',
+      record: {
+        title: 'Race cap',
+        description: 'Duplicate create event',
+        ref: 'race-count-test',
+        beacon: BEACON,
+        createdAt: '2026-07-07T00:00:00.000Z',
+      },
+    },
+  };
+}
+
+function vouchMessage() {
+  return {
+    kind: 'commit',
+    did: 'did:plc:race',
+    time_us: 1,
+    commit: {
+      operation: 'create',
+      collection: 'org.v-it.vouch',
+      rkey: 'same-rkey',
+      cid: 'vouch-cid',
+      record: {
+        subject: { uri: 'at://did:plc:race/org.v-it.cap/source' },
+        ref: 'race-count-test',
+        beacon: BEACON,
+        createdAt: '2026-07-07T00:00:00.000Z',
+      },
+    },
+  };
+}
+
+describe('explore jetstream ingest', () => {
+  test('serializes duplicate cap events for one record before updating beacon counts', async () => {
+    const env = { DB: new FakeD1() };
+    installWebSocketReplay([capMessage(), capMessage()]);
+
+    await streamEvents(env, null);
+
+    expect(env.DB.caps.size).toBe(1);
+    expect(env.DB.beacons.get(BEACON)).toMatchObject({ cap_count: 1, vouch_count: 0 });
+  });
+
+  test('serializes duplicate vouch events for one record before updating beacon counts', async () => {
+    const env = { DB: new FakeD1() };
+    installWebSocketReplay([vouchMessage(), vouchMessage()]);
+
+    await streamEvents(env, null);
+
+    expect(env.DB.vouches.size).toBe(1);
+    expect(env.DB.beacons.get(BEACON)).toMatchObject({ cap_count: 0, vouch_count: 1 });
+  });
+});