diff --git a/public/openapi/write/posts/pid/diffs.yaml b/public/openapi/write/posts/pid/diffs.yaml
index 5f0046781d..ea76f7ea66 100644
--- a/public/openapi/write/posts/pid/diffs.yaml
+++ b/public/openapi/write/posts/pid/diffs.yaml
@@ -27,14 +27,14 @@ get:
                   timestamps:
                     type: array
                     items:
-                      type: number
+                      type: string
                   revisions:
                     type: array
                     items:
                       type: object
                       properties:
                         timestamp:
-                          type: number
+                          type: string
                         username:
                           type: string
                   editable:
diff --git a/public/openapi/write/posts/pid/diffs/timestamp.yaml b/public/openapi/write/posts/pid/diffs/timestamp.yaml
index 205c7e1e37..15d942fc26 100644
--- a/public/openapi/write/posts/pid/diffs/timestamp.yaml
+++ b/public/openapi/write/posts/pid/diffs/timestamp.yaml
@@ -22,16 +22,4 @@ delete:
     '200':
       description: Post diff successfully deleted
       content:
-        application/json:
-          schema:
-            type: object
-            properties:
-              status:
-                $ref: ../../../../components/schemas/Status.yaml#/Status
-              response:
-                type: object
-                properties: {}
-    '400':
-      $ref: ../../../../components/responses/400.yaml#/400
-    '403':
-      $ref: ../../../../components/responses/403.yaml#/403
\ No newline at end of file
+        $ref: ../diffs.yaml#/get/responses/200/content
\ No newline at end of file
diff --git a/src/api/posts.js b/src/api/posts.js
index 3801c2598b..fdef453be3 100644
--- a/src/api/posts.js
+++ b/src/api/posts.js
@@ -266,7 +266,8 @@ postsAPI.getDiffs = async (caller, data) => {
 		privileges.users.isModerator(caller.uid, cid),
 	]);
 
-	timestamps.push(post.timestamp);
+	// timestamps returned by posts.diffs.list are strings
+	timestamps.push(String(post.timestamp));
 
 	return {
 		timestamps: timestamps,
diff --git a/test/api.js b/test/api.js
index a85143910d..20956ee361 100644
--- a/test/api.js
+++ b/test/api.js
@@ -18,6 +18,7 @@ const user = require('../src/user');
 const groups = require('../src/groups');
 const categories = require('../src/categories');
 const topics = require('../src/topics');
+const posts = require('../src/posts');
 const plugins = require('../src/plugins');
 const flags = require('../src/flags');
 const messaging = require('../src/messaging');
@@ -74,6 +75,18 @@ describe('API', async () => {
 					example: '',	// to be defined below...
 				},
 			],
+			'/posts/{pid}/diffs/{timestamp}': [
+				{
+					in: 'path',
+					name: 'pid',
+					example: '',	// to be defined below...
+				},
+				{
+					in: 'path',
+					name: 'timestamp',
+					example: '',	// to be defined below...
+				},
+			],
 		},
 	};
 
@@ -123,7 +136,7 @@ describe('API', async () => {
 		const testCategory = await categories.create({ name: 'test' });
 
 		// Post a new topic
-		const testTopic = await topics.post({
+		await topics.post({
 			uid: adminUid,
 			cid: testCategory.cid,
 			title: 'Test Topic',
@@ -142,6 +155,16 @@ describe('API', async () => {
 			content: 'Test topic 3 content',
 		});
 
+		// Create a post diff
+		await posts.edit({
+			uid: adminUid,
+			pid: unprivTopic.postData.pid,
+			content: 'Test topic 2 edited content',
+			req: {},
+		});
+		mocks.delete['/posts/{pid}/diffs/{timestamp}'][0].example = unprivTopic.postData.pid;
+		mocks.delete['/posts/{pid}/diffs/{timestamp}'][1].example = (await posts.diffs.list(unprivTopic.postData.pid))[0];
+
 		// Create a sample flag
 		await flags.create('post', 1, unprivUid, 'sample reasons', Date.now());