diff --git a/config.js.example b/config.js.example
index f73357e..1dff7d5 100644
--- a/config.js.example
+++ b/config.js.example
@@ -57,6 +57,12 @@ module.exports = {
   // Setting as -1 will disable max subscription limit.
   max_client_subs: -1,
 
+  // Maximum Known Events
+  // Used for knowing what events has been forwarded to client in order to prevent duplicates to be forwarded.
+  //
+  // Setting as 0 will store known events to memory without limits.
+  max_known_events: 1000,
+
   // Wait for every connected relays send EOSE.
   // Could improve accuracy on received events.
   //
diff --git a/worker_bouncer.js b/worker_bouncer.js
index ed64959..35535aa 100644
--- a/worker_bouncer.js
+++ b/worker_bouncer.js
@@ -7,7 +7,7 @@ const WebSocket = require("ws");
 const { validateEvent, nip19, matchFilters, mergeFilters, getFilterLimit } = require("nostr-tools");
 const nip42 = require("./nip42.js");
 
-let { relays, log_about_relays, private_keys, reconnect_time, wait_eose, pause_on_limit, max_eose_score, upstream_ratelimit_expiration, max_client_subs, idle_sessions, cache_relays, loadbalancer } = require(process.env.BOSTR_CONFIG_PATH || "./config");
+let { relays, log_about_relays, private_keys, reconnect_time, wait_eose, pause_on_limit, max_eose_score, upstream_ratelimit_expiration, max_client_subs, idle_sessions, cache_relays, loadbalancer, max_known_events } = require(process.env.BOSTR_CONFIG_PATH || "./config");
 
 log_about_relays = process.env.LOG_ABOUT_RELAYS || log_about_relays;
 
@@ -331,6 +331,9 @@ function newConn(addr, id, reconn_t = 0) {
         if (!relay.isLoadBalancer) client.events[data[1]].add(data[2]?.id);
         parentPort.postMessage({ type: "upstream_msg", id, data: JSON.stringify(data) });
 
+        if (max_known_events && client.events[data[1]].size > max_known_events)
+          client.events[data[1]].delete(client.events[data[1]].values().next().value);
+
         stats._global.rx++;
         stats[addr].rx++;