GraphQL Tester — In-Browser API Explorer
Test GraphQL API endpoints directly from your browser. Enter an endpoint URL, write a query, add variables and custom headers, then send the request via fetch(). Inspect the JSON response, view GraphQL errors separately from HTTP errors, and copy the full response. Free, browser-based, no proxy.
How to Use GraphQL Tester — In-Browser API Explorer
How to Use the GraphQL Tester
Step 1: Enter the Endpoint URL
Paste the full URL of the GraphQL endpoint in the endpoint field (e.g. https://api.example.com/graphql). All GraphQL APIs use a single POST endpoint regardless of the operation type.
Step 2: Write Your Query
Type or paste your GraphQL query in the Query editor. You can write queries, mutations, or subscriptions (subscriptions require WebSocket support and are not supported in this browser-based tester).
Example query: query GetUser($id: ID!) { user(id: $id) { name email } }
Step 3: Add Variables (optional)
Expand the Variables section and paste a JSON object with the values for any variables referenced in your query. For the example above: {"id": "123"}
Step 4: Add HTTP Headers (optional)
Expand the HTTP Headers section to add custom headers. Common use case: add an Authorization header for authenticated APIs: Authorization: Bearer YOUR_TOKEN_HERE
Content-Type: application/json and Accept: application/json are added automatically.
Step 5: Send the Request
Click Send or press Enter in the endpoint field. The request is sent directly from your browser using fetch(). The response panel shows the HTTP status, timing, and the full JSON response body.
Step 6: Read the Response
A successful GraphQL response contains a data field with your results. If the server returns GraphQL errors (e.g. field not found, auth failure), the response shows a GraphQL Errors badge. HTTP errors (4xx, 5xx) are shown separately.
Load Examples
Use the example buttons to load pre-built queries against public APIs:
- List countries (EU filter) — countries.trevorblades.com
- Country by code (with variables) — countries.trevorblades.com
- Rick and Morty characters — rickandmortyapi.com
- Schema introspection — returns all available types
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