diff --git a/api/src/processing/request.js b/api/src/processing/request.js
index 2e0cce52..901e8e96 100644
--- a/api/src/processing/request.js
+++ b/api/src/processing/request.js
@@ -70,6 +70,19 @@ export function createResponse(responseType, responseData) {
 
                     isHLS: responseData?.isHLS,
                 }
+
+                if (!response.audio.format) {
+                    if (response.type === "audio") {
+                        // audio response without a format is invalid
+                        return internalError();
+                    }
+                    delete response.audio;
+                }
+
+                if (!response.output.type || !response.output.filename) {
+                    // response without a type or filename is invalid
+                    return internalError();
+                }
                 break;
 
             case "picker":
diff --git a/web/src/lib/types/api.ts b/web/src/lib/types/api.ts
index 5e6e8a84..22e4a672 100644
--- a/web/src/lib/types/api.ts
+++ b/web/src/lib/types/api.ts
@@ -51,9 +51,9 @@ export type CobaltLocalProcessingResponse = {
     service: string,
     tunnel: string[],
 
-    output?: {
-        type?: string, // mimetype
-        filename?: string,
+    output: {
+        type: string, // mimetype
+        filename: string,
         metadata?: {
             album?: string,
             copyright?: string,