diff --git a/.changeset/weak-terms-shave.md b/.changeset/weak-terms-shave.md
new file mode 100644
index 0000000000000..1813edcdb2b5b
--- /dev/null
+++ b/.changeset/weak-terms-shave.md
@@ -0,0 +1,6 @@
+---
+"@rocket.chat/meteor": patch
+"@rocket.chat/rest-typings": patch
+---
+
+Add OpenAPI support for the Rocket.Chat emoji-custom.create API endpoints by migrating to a modern chained route definition syntax and utilizing shared AJV schemas for validation to enhance API documentation and ensure type safety through response validation.
diff --git a/apps/meteor/app/api/server/definition.ts b/apps/meteor/app/api/server/definition.ts
index 029c3ac223391..63db70e14e4a6 100644
--- a/apps/meteor/app/api/server/definition.ts
+++ b/apps/meteor/app/api/server/definition.ts
@@ -301,7 +301,7 @@ export type TypedThis<TOptions extends TypedOptions, TPath extends string = ''>
 		query: Record<string, unknown>;
 	}>;
 	bodyParams: TOptions['body'] extends ValidateFunction<infer Body> ? Body : never;
-
+	request: Request;
 	requestIp?: string;
 	route: string;
 	response: Response;
diff --git a/apps/meteor/app/api/server/v1/emoji-custom.ts b/apps/meteor/app/api/server/v1/emoji-custom.ts
index fa84d3cc6b995..c7fcfa7f698d9 100644
--- a/apps/meteor/app/api/server/v1/emoji-custom.ts
+++ b/apps/meteor/app/api/server/v1/emoji-custom.ts
@@ -1,7 +1,7 @@
 import { Media } from '@rocket.chat/core-services';
 import type { IEmojiCustom } from '@rocket.chat/core-typings';
 import { EmojiCustom } from '@rocket.chat/models';
-import { isEmojiCustomList } from '@rocket.chat/rest-typings';
+import { ajv, isEmojiCustomList } from '@rocket.chat/rest-typings';
 import { escapeRegExp } from '@rocket.chat/string-helpers';
 import { Meteor } from 'meteor/meteor';
 
@@ -11,6 +11,7 @@ import { insertOrUpdateEmoji } from '../../../emoji-custom/server/lib/insertOrUp
 import { uploadEmojiCustomWithBuffer } from '../../../emoji-custom/server/lib/uploadEmojiCustom';
 import { deleteEmojiCustom } from '../../../emoji-custom/server/methods/deleteEmojiCustom';
 import { settings } from '../../../settings/server';
+import type { ExtractRoutesFromAPI } from '../ApiClass';
 import { API } from '../api';
 import { getPaginationItems } from '../helpers/getPaginationItems';
 import { findEmojisCustom } from '../lib/emoji-custom';
@@ -103,45 +104,73 @@ API.v1.addRoute(
 	},
 );
 
-API.v1.addRoute(
+const emojiCustomCreateEndpoints = API.v1.post(
 	'emoji-custom.create',
-	{ authRequired: true },
 	{
-		async post() {
-			const emoji = await getUploadFormData(
-				{
-					request: this.request,
+		authRequired: true,
+		response: {
+			400: ajv.compile({
+				type: 'object',
+				properties: {
+					success: { type: 'boolean', enum: [false] },
+					stack: { type: 'string' },
+					error: { type: 'string' },
+					errorType: { type: 'string' },
+					details: { type: 'string' },
 				},
-				{ field: 'emoji', sizeLimit: settings.get('FileUpload_MaxFileSize') },
-			);
+				required: ['success'],
+				additionalProperties: false,
+			}),
+			200: ajv.compile<void>({
+				type: 'object',
+				properties: {
+					success: {
+						type: 'boolean',
+						enum: [true],
+					},
+				},
+				required: ['success'],
+				additionalProperties: false,
+			}),
+		},
+	},
+	async function action() {
+		const emoji = await getUploadFormData(
+			{
+				request: this.request,
+			},
+			{
+				field: 'emoji',
+				sizeLimit: settings.get('FileUpload_MaxFileSize'),
+			},
+		);
 
-			const { fields, fileBuffer, mimetype } = emoji;
+		const { fields, fileBuffer, mimetype } = emoji;
 
-			const isUploadable = await Media.isImage(fileBuffer);
-			if (!isUploadable) {
-				throw new Meteor.Error('emoji-is-not-image', "Emoji file provided cannot be uploaded since it's not an image");
-			}
+		const isUploadable = await Media.isImage(fileBuffer);
+		if (!isUploadable) {
+			throw new Meteor.Error('emoji-is-not-image', "Emoji file provided cannot be uploaded since it's not an image");
+		}
 
-			const [, extension] = mimetype.split('/');
-			fields.extension = extension;
+		const [, extension] = mimetype.split('/');
+		fields.extension = extension;
 
-			try {
-				const emojiData = await insertOrUpdateEmoji(this.userId, {
-					...fields,
-					newFile: true,
-					aliases: fields.aliases || '',
-					name: fields.name,
-					extension: fields.extension,
-				});
+		try {
+			const emojiData = await insertOrUpdateEmoji(this.userId, {
+				...fields,
+				newFile: true,
+				aliases: fields.aliases || '',
+				name: fields.name,
+				extension: fields.extension,
+			});
 
-				await uploadEmojiCustomWithBuffer(this.userId, fileBuffer, mimetype, emojiData);
-			} catch (e) {
-				SystemLogger.error(e);
-				return API.v1.failure();
-			}
+			await uploadEmojiCustomWithBuffer(this.userId, fileBuffer, mimetype, emojiData);
+		} catch (e) {
+			SystemLogger.error(e);
+			return API.v1.failure();
+		}
 
-			return API.v1.success();
-		},
+		return API.v1.success();
 	},
 );
 
@@ -219,3 +248,12 @@ API.v1.addRoute(
 		},
 	},
 );
+
+type EmojiCustomCreateEndpoints = ExtractRoutesFromAPI<typeof emojiCustomCreateEndpoints>;
+
+export type EmojiCustomEndpoints = EmojiCustomCreateEndpoints;
+
+declare module '@rocket.chat/rest-typings' {
+	// eslint-disable-next-line @typescript-eslint/naming-convention, @typescript-eslint/no-empty-interface
+	interface Endpoints extends EmojiCustomCreateEndpoints {}
+}
diff --git a/packages/rest-typings/src/v1/emojiCustom.ts b/packages/rest-typings/src/v1/emojiCustom.ts
index ad67bbf7d0e9b..dda81acbcb3fa 100644
--- a/packages/rest-typings/src/v1/emojiCustom.ts
+++ b/packages/rest-typings/src/v1/emojiCustom.ts
@@ -67,9 +67,6 @@ export type EmojiCustomEndpoints = {
 	'/v1/emoji-custom.delete': {
 		POST: (params: emojiCustomDeleteProps) => void;
 	};
-	'/v1/emoji-custom.create': {
-		POST: (params: { emoji: ICustomEmojiDescriptor }) => void;
-	};
 	'/v1/emoji-custom.update': {
 		POST: (params: { emoji: ICustomEmojiDescriptor }) => void;
 	};