GraphQL Query Tester

Write, validate, and run GraphQL queries against any endpoint — with live JSON responses

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Response

Enter a GraphQL endpoint and query, then click Send Query

What is a GraphQL Query Tester?

A GraphQL query tester lets you write GraphQL documents and send them to a real GraphQL endpoint to see the live response. GraphQL is a query language and runtime developed by Meta that lets clients request exactly the fields they need from an API — no over-fetching or under-fetching. Instead of multiple REST endpoints, a GraphQL API exposes a single endpoint that accepts query, mutation, and subscription operations.

This tool validates your GraphQL syntax in the browser before anything is sent, then forwards the request through our server to bypass CORS restrictions — so you can test public and development GraphQL APIs with variables, headers, and authentication, then inspect the formatted JSON response, headers, status code, and timing.

How to Use

  1. Enter the endpoint URL — Paste the full GraphQL API URL (for example https://countries.trevorblades.com/) into the Endpoint field.
  2. Write your query — Paste or type a GraphQL operation in the Query box. Use Valid Example to load a working query, or Invalid Example to see how broken syntax is caught before sending.
  3. Add variables and operation name — If your query declares $variables, provide them as a JSON object and set the operation name so the server knows which operation to run.
  4. Add headers — Click + Add Header for things like Authorization: Bearer <token> on protected endpoints.
  5. Click Send Query — The query is validated locally, sent through our proxy, and the response appears on the right with status, headers, size, and duration.

Frequently Asked Questions

What is the difference between a query and a mutation?

A query reads data and is safe to repeat, while a mutation writes data (create, update, delete) and can have side effects. GraphQL servers expose both operations on the same endpoint. This tool sends either — write the correct operation keyword at the top of your document.

Why does my request fail even though the syntax is valid?

The server may require authentication (add an Authorization header), the endpoint may not allow cross-origin requests or be reachable, the query may reference fields that do not exist in the schema, or the request may time out after 30 seconds. GraphQL APIs return structured errors in the response body — check the response panel for details.

Is my GraphQL query data stored?

No. Your query is sent through our proxy only to reach the target GraphQL server and is never logged, stored, or retained. Your queries and any headers you add are visible only in your own browser tab.

Can I test localhost or private GraphQL APIs?

No. The proxy cannot reach localhost, 127.0.0.1, or private network addresses for security reasons. Use this tool for public or internet-reachable development APIs only.

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