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How to Query a GraphQL API

Sending a Query

  1. Open the GraphQL Tester.
  2. Enter your GraphQL endpoint URL.
  3. Write your query in the Query textarea.
  4. Add variables as JSON in the Variables textarea (optional).
  5. Click Send.

Example

Query:

query GetUser($id: ID!) { user(id: $id) { name email } }

Variables:

{"id": "42"}

Schema Explorer

Click the Explorer tab on the right, then click the refresh button (↻) to fetch the schema via introspection. You can browse all queries, mutations, and types with their fields, arguments, and descriptions. Use the search filter to find types quickly. Introspection uses the same HTTP relay as Send, so it works across origins without CORS blocking the response.

HTTP relay

JSON GraphQL operations and introspection go through the DevToolSets relay (same as REST without files). GraphQL multipart file uploads use the browser directly. Subscriptions (SSE/WebSocket) always connect from the browser only.

File Uploads

For GraphQL file uploads (multipart spec), use the File Fields section in the left panel:

  1. Click "+ Add Field"
  2. Set the variable path (e.g. variables.file)
  3. Attach one or more files
  4. The request is automatically sent as multipart/form-data

Subscriptions

The Subscriptions panel at the bottom supports SSE and WebSocket connections. Add a subscription, enter the endpoint URL, choose SSE or WS, and click Connect. Messages appear in real-time with timestamps and auto-formatted JSON.