diff --git a/src/lib/openapi/index.ts b/src/lib/openapi/index.ts
index 3fef56e82c..59f0e20be2 100644
--- a/src/lib/openapi/index.ts
+++ b/src/lib/openapi/index.ts
@@ -33,6 +33,7 @@ import { variantsSchema } from './spec/variants-schema';
 import { versionSchema } from './spec/version-schema';
 import { environmentsSchema } from './spec/environments-schema';
 import { sortOrderSchema } from './spec/sort-order-schema';
+import { splashSchema } from './spec/splash-schema';
 
 // Schemas must have $id property on the form "#/components/schemas/mySchema".
 export type SchemaId = typeof schemas[keyof typeof schemas]['$id'];
@@ -82,6 +83,7 @@ export const schemas = {
     projectSchema,
     projectsSchema,
     sortOrderSchema,
+    splashSchema,
     strategySchema,
     tagSchema,
     tagsSchema,
diff --git a/src/lib/openapi/spec/splash-schema.ts b/src/lib/openapi/spec/splash-schema.ts
new file mode 100644
index 0000000000..c21cad3f6a
--- /dev/null
+++ b/src/lib/openapi/spec/splash-schema.ts
@@ -0,0 +1,22 @@
+import { FromSchema } from 'json-schema-to-ts';
+
+export const splashSchema = {
+    $id: '#/components/schemas/splashSchema',
+    type: 'object',
+    additionalProperties: false,
+    required: ['userId', 'splashId', 'seen'],
+    properties: {
+        userId: {
+            type: 'number',
+        },
+        splashId: {
+            type: 'string',
+        },
+        seen: {
+            type: 'boolean',
+        },
+    },
+    components: {},
+} as const;
+
+export type SplashSchema = FromSchema<typeof splashSchema>;
diff --git a/src/lib/routes/admin-api/user-splash.ts b/src/lib/routes/admin-api/user-splash.ts
index d0f21c8fe8..d05c701aaf 100644
--- a/src/lib/routes/admin-api/user-splash.ts
+++ b/src/lib/routes/admin-api/user-splash.ts
@@ -1,5 +1,4 @@
 import { Response } from 'express';
-
 import Controller from '../controller';
 import { Logger } from '../../logger';
 import { IUnleashConfig } from '../../types/option';
@@ -7,31 +6,47 @@ import { IUnleashServices } from '../../types/services';
 import UserSplashService from '../../services/user-splash-service';
 import { IAuthRequest } from '../unleash-types';
 import { NONE } from '../../types/permissions';
-
-interface ISplashBody {
-    seen: boolean;
-    splashId: string;
-}
+import { OpenApiService } from '../../services/openapi-service';
+import { createResponseSchema } from '../../openapi';
+import { splashSchema, SplashSchema } from '../../openapi/spec/splash-schema';
 
 class UserSplashController extends Controller {
     private logger: Logger;
 
     private userSplashService: UserSplashService;
 
+    private openApiService: OpenApiService;
+
     constructor(
         config: IUnleashConfig,
-        { userSplashService }: Pick<IUnleashServices, 'userSplashService'>,
+        {
+            userSplashService,
+            openApiService,
+        }: Pick<IUnleashServices, 'userSplashService' | 'openApiService'>,
     ) {
         super(config);
         this.logger = config.getLogger('splash-controller.ts');
         this.userSplashService = userSplashService;
+        this.openApiService = openApiService;
 
-        this.post('/:id', this.updateSplashSettings, NONE);
+        this.route({
+            method: 'post',
+            path: '/:id',
+            handler: this.updateSplashSettings,
+            permission: NONE,
+            middleware: [
+                openApiService.validPath({
+                    tags: ['admin'],
+                    operationId: 'updateSplashSettings',
+                    responses: { 200: createResponseSchema('splashSchema') },
+                }),
+            ],
+        });
     }
 
     private async updateSplashSettings(
-        req: IAuthRequest<any, any, ISplashBody, any>,
-        res: Response,
+        req: IAuthRequest<{ id: string }>,
+        res: Response<SplashSchema>,
     ): Promise<void> {
         const { user } = req;
         const { id } = req.params;
@@ -41,8 +56,13 @@ class UserSplashController extends Controller {
             userId: user.id,
             seen: true,
         };
-        const updated = await this.userSplashService.updateSplash(splash);
-        res.json(updated);
+
+        this.openApiService.respondWithValidation(
+            200,
+            res,
+            splashSchema.$id,
+            await this.userSplashService.updateSplash(splash),
+        );
     }
 }
 
diff --git a/src/test/e2e/api/openapi/__snapshots__/openapi.e2e.test.ts.snap b/src/test/e2e/api/openapi/__snapshots__/openapi.e2e.test.ts.snap
index 00164a9947..42a291b6df 100644
--- a/src/test/e2e/api/openapi/__snapshots__/openapi.e2e.test.ts.snap
+++ b/src/test/e2e/api/openapi/__snapshots__/openapi.e2e.test.ts.snap
@@ -649,6 +649,26 @@ Object {
         },
         "type": "object",
       },
+      "splashSchema": Object {
+        "additionalProperties": false,
+        "properties": Object {
+          "seen": Object {
+            "type": "boolean",
+          },
+          "splashId": Object {
+            "type": "string",
+          },
+          "userId": Object {
+            "type": "number",
+          },
+        },
+        "required": Array [
+          "userId",
+          "splashId",
+          "seen",
+        ],
+        "type": "object",
+      },
       "strategySchema": Object {
         "additionalProperties": false,
         "properties": Object {
@@ -2364,6 +2384,36 @@ Object {
         ],
       },
     },
+    "/api/admin/splash/{id}": Object {
+      "post": Object {
+        "operationId": "updateSplashSettings",
+        "parameters": Array [
+          Object {
+            "in": "path",
+            "name": "id",
+            "required": true,
+            "schema": Object {
+              "type": "string",
+            },
+          },
+        ],
+        "responses": Object {
+          "200": Object {
+            "content": Object {
+              "application/json": Object {
+                "schema": Object {
+                  "$ref": "#/components/schemas/splashSchema",
+                },
+              },
+            },
+            "description": "splashSchema",
+          },
+        },
+        "tags": Array [
+          "admin",
+        ],
+      },
+    },
     "/api/admin/ui-config": Object {
       "get": Object {
         "operationId": "getUIConfig",