diff --git a/src/policies/anti-duplication-policy.ts b/src/policies/anti-duplication-policy.ts
index c51c3e0..7bb032f 100755
--- a/src/policies/anti-duplication-policy.ts
+++ b/src/policies/anti-duplication-policy.ts
@@ -3,33 +3,11 @@
 import { readLines } from 'https://deno.land/std@0.178.0/io/mod.ts';
 import { Keydb } from 'https://deno.land/x/keydb@1.0.0/sqlite.ts';
 
+import type { InputMessage, OutputMessage } from '../types.ts';
+
 const ANTI_DUPLICATION_TTL = Number(Deno.env.get('ANTI_DUPLICATION_TTL') || 60000);
 const ANTI_DUPLICATION_MIN_LENGTH = Number(Deno.env.get('ANTI_DUPLICATION_MIN_LENGTH') || 50);
 
-interface InputMessage {
-  type: 'new' | 'lookback';
-  event: Event;
-  receivedAt: number;
-  sourceType: 'IP4' | 'IP6' | 'Import' | 'Stream' | 'Sync';
-  sourceInfo: string;
-}
-
-interface OutputMessage {
-  id: string;
-  action: 'accept' | 'reject' | 'shadowReject';
-  msg: string;
-}
-
-interface Event {
-  id: string;
-  sig: string;
-  kind: number;
-  tags: string[][];
-  pubkey: string;
-  content: string;
-  created_at: number;
-}
-
 /** https://stackoverflow.com/a/8831937 */
 function hashCode(str: string): number {
   let hash = 0;
diff --git a/src/policies/hellthread-policy.ts b/src/policies/hellthread-policy.ts
index d89f9c9..2120dbf 100755
--- a/src/policies/hellthread-policy.ts
+++ b/src/policies/hellthread-policy.ts
@@ -1,32 +1,10 @@
 #!/usr/bin/env -S deno run
 import { readLines } from 'https://deno.land/std@0.178.0/io/mod.ts';
 
+import type { InputMessage, OutputMessage } from '../types.ts';
+
 const HELLTHREAD_LIMIT = Number(Deno.env.get('HELLTHREAD_LIMIT') || 100);
 
-interface InputMessage {
-  type: 'new' | 'lookback';
-  event: Event;
-  receivedAt: number;
-  sourceType: 'IP4' | 'IP6' | 'Import' | 'Stream' | 'Sync';
-  sourceInfo: string;
-}
-
-interface OutputMessage {
-  id: string;
-  action: 'accept' | 'reject' | 'shadowReject';
-  msg: string;
-}
-
-interface Event {
-  id: string;
-  sig: string;
-  kind: number;
-  tags: string[][];
-  pubkey: string;
-  content: string;
-  created_at: number;
-}
-
 function handleMessage(msg: InputMessage): OutputMessage {
   if (msg.event.kind === 1) {
     const p = msg.event.tags.filter((tag) => tag[0] === 'p');
diff --git a/src/policies/noop-policy.ts b/src/policies/noop-policy.ts
index e3361df..912ed46 100755
--- a/src/policies/noop-policy.ts
+++ b/src/policies/noop-policy.ts
@@ -1,29 +1,7 @@
 #!/usr/bin/env -S deno run
 import { readLines } from 'https://deno.land/std@0.178.0/io/mod.ts';
 
-interface InputMessage {
-  type: 'new' | 'lookback';
-  event: Event;
-  receivedAt: number;
-  sourceType: 'IP4' | 'IP6' | 'Import' | 'Stream' | 'Sync';
-  sourceInfo: string;
-}
-
-interface OutputMessage {
-  id: string;
-  action: 'accept' | 'reject' | 'shadowReject';
-  msg: string;
-}
-
-interface Event {
-  id: string;
-  sig: string;
-  kind: number;
-  tags: string[][];
-  pubkey: string;
-  content: string;
-  created_at: number;
-}
+import type { InputMessage, OutputMessage } from '../types.ts';
 
 function handleMessage(msg: InputMessage): OutputMessage {
   return {
diff --git a/src/policies/rate-limit-policy.ts b/src/policies/rate-limit-policy.ts
index 54da6ec..1e14f2f 100755
--- a/src/policies/rate-limit-policy.ts
+++ b/src/policies/rate-limit-policy.ts
@@ -3,41 +3,19 @@
 import { readLines } from 'https://deno.land/std@0.178.0/io/mod.ts';
 import { Keydb } from 'https://deno.land/x/keydb@1.0.0/sqlite.ts';
 
+import type { InputMessage, OutputMessage } from '../types.ts';
+
 const IP_WHITELIST = (Deno.env.get('IP_WHITELIST') || '').split(',');
 
 const RATE_LIMIT_INTERVAL = Number(Deno.env.get('RATE_LIMIT_INTERVAL') || 60000);
 const RATE_LIMIT_MAX = Number(Deno.env.get('RATE_LIMIT_MAX') || 10);
 
-interface InputMessage {
-  type: 'new' | 'lookback';
-  event: Event;
-  receivedAt: number;
-  sourceType: 'IP4' | 'IP6' | 'Import' | 'Stream' | 'Sync';
-  sourceInfo: string;
-}
-
-interface OutputMessage {
-  id: string;
-  action: 'accept' | 'reject' | 'shadowReject';
-  msg: string;
-}
-
-interface Event {
-  id: string;
-  sig: string;
-  kind: number;
-  tags: string[][];
-  pubkey: string;
-  content: string;
-  created_at: number;
-}
-
 async function handleMessage(msg: InputMessage): Promise<OutputMessage> {
   if ((msg.sourceType === 'IP4' || msg.sourceType === 'IP6') && !IP_WHITELIST.includes(msg.sourceInfo)) {
     const db = new Keydb('sqlite:///tmp/strfry-rate-limit-policy.sqlite3');
     const count = await db.get<number>(msg.sourceInfo) || 0;
     await db.set(msg.sourceInfo, count + 1, RATE_LIMIT_INTERVAL);
-  
+
     if (count >= RATE_LIMIT_MAX) {
       return {
         id: msg.event.id,
diff --git a/src/policies/read-only-policy.ts b/src/policies/read-only-policy.ts
index f1e11af..998dcc6 100755
--- a/src/policies/read-only-policy.ts
+++ b/src/policies/read-only-policy.ts
@@ -2,29 +2,7 @@
 //bin/true; exec deno run -A "$0" "$@"
 import { readLines } from 'https://deno.land/std@0.178.0/io/mod.ts';
 
-interface InputMessage {
-  type: 'new' | 'lookback';
-  event: Event;
-  receivedAt: number;
-  sourceType: 'IP4' | 'IP6' | 'Import' | 'Stream' | 'Sync';
-  sourceInfo: string;
-}
-
-interface OutputMessage {
-  id: string;
-  action: 'accept' | 'reject' | 'shadowReject';
-  msg: string;
-}
-
-interface Event {
-  id: string;
-  sig: string;
-  kind: number;
-  tags: string[][];
-  pubkey: string;
-  content: string;
-  created_at: number;
-}
+import type { InputMessage, OutputMessage } from '../types.ts';
 
 function handleMessage(msg: InputMessage): OutputMessage {
   return {
diff --git a/src/types.ts b/src/types.ts
new file mode 100644
index 0000000..473a3f7
--- /dev/null
+++ b/src/types.ts
@@ -0,0 +1,25 @@
+interface InputMessage {
+  type: 'new' | 'lookback';
+  event: Event;
+  receivedAt: number;
+  sourceType: 'IP4' | 'IP6' | 'Import' | 'Stream' | 'Sync';
+  sourceInfo: string;
+}
+
+interface OutputMessage {
+  id: string;
+  action: 'accept' | 'reject' | 'shadowReject';
+  msg: string;
+}
+
+interface Event<K extends number = number> {
+  id: string;
+  sig: string;
+  kind: K;
+  tags: string[][];
+  pubkey: string;
+  content: string;
+  created_at: number;
+}
+
+export type { Event, InputMessage, OutputMessage };