diff --git a/apify-api/openapi/openapi.yaml b/apify-api/openapi/openapi.yaml
index af3cc58791..b3af5d2fb9 100644
--- a/apify-api/openapi/openapi.yaml
+++ b/apify-api/openapi/openapi.yaml
@@ -510,6 +510,8 @@ paths:
     $ref: "paths/actors/acts@{actorId}@run-sync.yaml"
   "/v2/acts/{actorId}/run-sync-get-dataset-items":
     $ref: "paths/actors/acts@{actorId}@run-sync-get-dataset-items.yaml"
+  "/v2/acts/{actorId}/validate-input":
+    $ref: "paths/actors/acts@{actorId}@validate-input.yaml"
   "/v2/acts/{actorId}/runs/{runId}/resurrect":
     $ref: "paths/actors/acts@{actorId}@runs@{runId}@resurrect.yaml"
   "/v2/acts/{actorId}/runs/last":
diff --git a/apify-api/openapi/paths/actors/acts@{actorId}@validate-input.yaml b/apify-api/openapi/paths/actors/acts@{actorId}@validate-input.yaml
new file mode 100644
index 0000000000..34babc84c7
--- /dev/null
+++ b/apify-api/openapi/paths/actors/acts@{actorId}@validate-input.yaml
@@ -0,0 +1,42 @@
+post:
+  tags:
+    - Actors
+  summary: Validate Actor input
+  description: |
+    Validates whether the provided JSON payload matches the Actor input schema without starting a run.
+    Use this endpoint before triggering an Actor to catch schema violations and return actionable error messages.
+  operationId: act_validate_input_post
+  parameters:
+    - $ref: "../../components/parameters/runAndBuildParameters.yaml#/actorId"
+  requestBody:
+    description: JSON payload to validate against the Actor input schema.
+    required: true
+    content:
+      application/json:
+        schema:
+          type: object
+          additionalProperties: true
+  responses:
+    "204":
+      $ref: ../../components/responses/NoContent.yaml
+    "400":
+      $ref: ../../components/responses/BadRequest.yaml
+    "401":
+      $ref: ../../components/responses/Unauthorized.yaml
+    "403":
+      $ref: ../../components/responses/Forbidden.yaml
+    "404":
+      description: Not found - the requested resource was not found.
+      content:
+        application/json:
+          schema:
+            $ref: "../../components/schemas/common/errors/ActorErrors.yaml#/ActorNotFoundError"
+    "405":
+      $ref: ../../components/responses/MethodNotAllowed.yaml
+    "413":
+      $ref: ../../components/responses/PayloadTooLarge.yaml
+    "415":
+      $ref: ../../components/responses/UnsupportedMediaType.yaml
+    "429":
+      $ref: ../../components/responses/TooManyRequests.yaml
+  deprecated: false