API Playground

Test REST and GraphQL APIs, inspect responses, and debug WebSocket, SSE, Socket.IO, and MQTT connections directly from your browser.

Browser-direct · No proxy · No account

API testing workspace

Credentials stay in memory
Ready to send · Pollinations AI text generation · No API key

Query parameters

Requests go directly from your browser to the target service.KitVerse does not receive or log them. The target service must allow cross-origin requests.
Response

Response inspector

Ready to inspect a response

Configure a request and select Send. Status, timing, size, and headers will appear here.

No URLs, headers, bodies, or events are saved. Use credentials only with trusted endpoints.
About this tool

Made for the task at hand.

A focused API platform for developers who need to exercise an endpoint without creating an account or uploading a collection. Build REST and GraphQL requests, inspect status, timing, headers, and bodies, then move to realtime protocols with a shared event log. Connections go directly from your browser to the endpoint you choose, never through a KitVerse proxy.

How to use

  1. Choose REST or GraphQL, enter a complete HTTP(S) endpoint, configure parameters, headers, authorization, body, query, or variables, then select Send request.
  2. Review response status, elapsed time, size, headers, and body. Copy or download the visible response, or cancel an in-flight request.
  3. Open Realtime and choose WebSocket, SSE, Socket.IO, or MQTT. Connect explicitly, then send messages, emit named events, or publish and subscribe to MQTT topics while watching the timestamped event log.
Your work stays yours.
Tool inputs are processed locally in your browser and are never sent to KitVerse servers. Clear the workspace when using a shared device.
Common questions
Does this API tester use a KitVerse server or proxy?

No. Requests and connections originate in your browser and go directly to the target service. KitVerse does not receive the URL, credentials, request body, response, or event payloads. The target service can still receive and log whatever you send.

Why can’t I call an endpoint that works in cURL or Postman?

Browser API testing must follow web security rules. REST, GraphQL, and SSE targets need suitable CORS headers, HTTPS pages block insecure mixed content, and native EventSource cannot add custom headers. This static tool does not bypass those controls with a proxy.

Which realtime protocol should I choose?

Use WebSocket for native bidirectional sockets, SSE for one-way server event streams, Socket.IO only for servers implementing that protocol, and MQTT over WebSocket for topic-based publish/subscribe. Plain tcp:// MQTT and arbitrary TCP connections are not available in a browser.

Are credentials and API requests saved?

No. URLs, headers, tokens, bodies, responses, and realtime events remain in page memory and disappear on refresh. Nothing is written to localStorage by this workspace. Export only when you explicitly choose to download a response or event log.

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