diff --git a/packages/frontend-plugin-api/api-report.md b/packages/frontend-plugin-api/api-report.md
index 266315c396..9c1907775b 100644
--- a/packages/frontend-plugin-api/api-report.md
+++ b/packages/frontend-plugin-api/api-report.md
@@ -919,7 +919,7 @@ export interface ExtensionBlueprint<
           config?: T['config'];
           inputs?: ResolveInputValueOverrides<NonNullable<T['inputs']>>;
         },
-      ) => ExtensionDataContainer<T['output']>,
+      ) => ExtensionDataContainer<NonNullable<T['output']>>,
       context: {
         node: AppNode;
         apis: ApiHolder;
@@ -932,7 +932,9 @@ export interface ExtensionBlueprint<
       },
     ): Iterable<UFactoryOutput> &
       VerifyExtensionFactoryOutput<
-        AnyExtensionDataRef extends UNewOutput ? T['output'] : UNewOutput,
+        AnyExtensionDataRef extends UNewOutput
+          ? NonNullable<T['output']>
+          : UNewOutput,
         UFactoryOutput
       >;
   }): ExtensionDefinition<{
@@ -969,14 +971,14 @@ export type ExtensionBlueprintParameters = {
   kind: string;
   namespace?: string;
   name?: string;
-  params: object;
+  params?: object;
   configInput?: {
     [K in string]: any;
   };
   config?: {
     [K in string]: any;
   };
-  output: AnyExtensionDataRef;
+  output?: AnyExtensionDataRef;
   inputs?: {
     [KName in string]: ExtensionInput<
       AnyExtensionDataRef,
@@ -1157,7 +1159,7 @@ export type ExtensionDefinitionParameters = {
   config?: {
     [K in string]: any;
   };
-  output: AnyExtensionDataRef;
+  output?: AnyExtensionDataRef;
   inputs?: {
     [KName in string]: ExtensionInput<
       AnyExtensionDataRef,
diff --git a/packages/frontend-plugin-api/src/wiring/createExtension.ts b/packages/frontend-plugin-api/src/wiring/createExtension.ts
index d8b53c4aaa..8838f7bf9a 100644
--- a/packages/frontend-plugin-api/src/wiring/createExtension.ts
+++ b/packages/frontend-plugin-api/src/wiring/createExtension.ts
@@ -148,7 +148,7 @@ export type ExtensionDefinitionParameters = {
   name?: string;
   configInput?: { [K in string]: any };
   config?: { [K in string]: any };
-  output: AnyExtensionDataRef;
+  output?: AnyExtensionDataRef;
   inputs?: {
     [KName in string]: ExtensionInput<
       AnyExtensionDataRef,
diff --git a/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts b/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts
index 85823b96a5..77d078f257 100644
--- a/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts
+++ b/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts
@@ -86,10 +86,10 @@ export type ExtensionBlueprintParameters = {
   kind: string;
   namespace?: string;
   name?: string;
-  params: object;
+  params?: object;
   configInput?: { [K in string]: any };
   config?: { [K in string]: any };
-  output: AnyExtensionDataRef;
+  output?: AnyExtensionDataRef;
   inputs?: {
     [KName in string]: ExtensionInput<
       AnyExtensionDataRef,
@@ -171,7 +171,7 @@ export interface ExtensionBlueprint<
           config?: T['config'];
           inputs?: ResolveInputValueOverrides<NonNullable<T['inputs']>>;
         },
-      ) => ExtensionDataContainer<T['output']>,
+      ) => ExtensionDataContainer<NonNullable<T['output']>>,
       context: {
         node: AppNode;
         apis: ApiHolder;
@@ -184,7 +184,9 @@ export interface ExtensionBlueprint<
       },
     ): Iterable<UFactoryOutput> &
       VerifyExtensionFactoryOutput<
-        AnyExtensionDataRef extends UNewOutput ? T['output'] : UNewOutput,
+        AnyExtensionDataRef extends UNewOutput
+          ? NonNullable<T['output']>
+          : UNewOutput,
         UFactoryOutput
       >;
   }): ExtensionDefinition<{
diff --git a/packages/frontend-plugin-api/src/wiring/resolveExtensionDefinition.ts b/packages/frontend-plugin-api/src/wiring/resolveExtensionDefinition.ts
index 49d623ad68..870fb258f5 100644
--- a/packages/frontend-plugin-api/src/wiring/resolveExtensionDefinition.ts
+++ b/packages/frontend-plugin-api/src/wiring/resolveExtensionDefinition.ts
@@ -116,7 +116,6 @@ export type ResolveExtensionId<
   kind: infer IKind extends string | undefined;
   namespace: infer INamespace extends string | undefined;
   name: infer IName extends string | undefined;
-  output: any;
 }>
   ? [string | undefined] extends [IKind | INamespace | IName]
     ? never
diff --git a/packages/frontend-test-utils/api-report.md b/packages/frontend-test-utils/api-report.md
index 3dcbacac57..31e293e434 100644
--- a/packages/frontend-test-utils/api-report.md
+++ b/packages/frontend-test-utils/api-report.md
@@ -37,7 +37,7 @@ export function createExtensionTester<T extends ExtensionDefinitionParameters>(
   options?: {
     config?: T['configInput'];
   },
-): ExtensionTester<T['output']>;
+): ExtensionTester<NonNullable<T['output']>>;
 
 export { ErrorWithContext };
 
@@ -78,7 +78,7 @@ export class ExtensionTester<UOutput extends AnyExtensionDataRef> {
   // (undocumented)
   query<T extends ExtensionDefinitionParameters>(
     extension: ExtensionDefinition<T>,
-  ): ExtensionQuery<T['output']>;
+  ): ExtensionQuery<NonNullable<T['output']>>;
   // (undocumented)
   reactElement(): JSX.Element;
 }
diff --git a/packages/frontend-test-utils/src/app/createExtensionTester.tsx b/packages/frontend-test-utils/src/app/createExtensionTester.tsx
index 01687abc2d..1345edfa1d 100644
--- a/packages/frontend-test-utils/src/app/createExtensionTester.tsx
+++ b/packages/frontend-test-utils/src/app/createExtensionTester.tsx
@@ -79,7 +79,7 @@ export class ExtensionTester<UOutput extends AnyExtensionDataRef> {
   static forSubject<T extends ExtensionDefinitionParameters>(
     subject: ExtensionDefinition<T>,
     options?: { config?: T['configInput'] },
-  ): ExtensionTester<T['output']> {
+  ): ExtensionTester<NonNullable<T['output']>> {
     const tester = new ExtensionTester();
     tester.add(subject, options as T['configInput'] & {});
     return tester;
@@ -137,7 +137,7 @@ export class ExtensionTester<UOutput extends AnyExtensionDataRef> {
 
   query<T extends ExtensionDefinitionParameters>(
     extension: ExtensionDefinition<T>,
-  ): ExtensionQuery<T['output']> {
+  ): ExtensionQuery<NonNullable<T['output']>> {
     const tree = this.#resolveTree();
 
     const actualId = this.#extensions.find(e => e.definition === extension)?.id;
@@ -240,6 +240,6 @@ export class ExtensionTester<UOutput extends AnyExtensionDataRef> {
 export function createExtensionTester<T extends ExtensionDefinitionParameters>(
   subject: ExtensionDefinition<T>,
   options?: { config?: T['configInput'] },
-): ExtensionTester<T['output']> {
+): ExtensionTester<NonNullable<T['output']>> {
   return ExtensionTester.forSubject(subject, options);
 }