diff --git a/package.json b/package.json
index 2eb5eb56..5097becd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "hawk.api",
-  "version": "1.5.3",
+  "version": "1.5.4",
   "main": "index.ts",
   "license": "BUSL-1.1",
   "scripts": {
diff --git a/src/mongo.ts b/src/mongo.ts
index 60a2d5ff..27bfd1f0 100644
--- a/src/mongo.ts
+++ b/src/mongo.ts
@@ -7,12 +7,20 @@ const eventsDBUrl = process.env.MONGO_EVENTS_DB_URL || 'mongodb://localhost:2701
 
 const reconnectTries = Number(process.env.MONGO_RECONNECT_TRIES) || 60;
 const reconnectInterval = Number(process.env.MONGO_RECONNECT_INTERVAL) || 1000;
+const maxPoolSize = Number(process.env.MONGO_MAX_POOL_SIZE) || 30;
 
 /**
  * serverSelectionTimeoutMS bounds how long an op waits for an available
  * server — without it queries hang forever during an outage.
+ *
+ * maxPoolSize caps sockets per client (driver default 100 lets API replicas
+ * alone exhaust the server-side 1024 limit); maxIdleTimeMS closes sockets
+ * left idle after spikes (default 0 keeps them forever).
  */
-const connectionConfig: MongoClientOptions = withMongoMetrics({
+const connectionConfig = (appName: string): MongoClientOptions => withMongoMetrics({
+  appName,
+  maxPoolSize,
+  maxIdleTimeMS: 60000,
   serverSelectionTimeoutMS: 10000,
   socketTimeoutMS: 45000,
   retryWrites: true,
@@ -77,7 +85,7 @@ async function connectWithRetry(name: string, url: string): Promise<MongoClient>
   let lastError = 'unknown error';
 
   for (let attempt = 1; attempt <= reconnectTries; attempt++) {
-    const client = new MongoClient(url, connectionConfig);
+    const client = new MongoClient(url, connectionConfig(`hawk-api-${name}`));
 
     try {
       await client.connect();
diff --git a/src/resolvers/project.js b/src/resolvers/project.js
index 18da81f3..7e4bf7fe 100644
--- a/src/resolvers/project.js
+++ b/src/resolvers/project.js
@@ -20,6 +20,7 @@ const EVENTS_PAYLOAD_RELEASE_INDEX_NAME = 'payloadRelease';
 const GROUPING_TIMESTAMP_INDEX_NAME = 'groupingTimestamp';
 const GROUPING_TIMESTAMP_AND_LAST_REPETITION_TIME_AND_ID_INDEX_NAME = 'groupingTimestampAndLastRepetitionTimeAndId';
 const GROUPING_TIMESTAMP_AND_GROUP_HASH_INDEX_NAME = 'groupingTimestampAndGroupHash';
+const DAILY_EVENTS_GROUP_HASH_INDEX_NAME = 'groupHash';
 const MAX_SEARCH_QUERY_LENGTH = 50;
 const FALLBACK_EVENT_TITLE = 'Unknown';
 
@@ -183,6 +184,12 @@ module.exports = {
         name: GROUPING_TIMESTAMP_AND_LAST_REPETITION_TIME_AND_ID_INDEX_NAME,
       });
 
+      await projectDailyEventsCollection.createIndex({
+        groupHash: 1,
+      }, {
+        name: DAILY_EVENTS_GROUP_HASH_INDEX_NAME,
+      });
+
       await projectEventsCollection.createIndex({
         'payload.release': 1,
       },