Free GraphQL Testing Tool

Test GraphQL APIs
Online — Free & Instant

Send GraphQL queries, mutations & introspection requests to any endpoint. Add custom headers, variables, and operation names. View formatted JSON responses with syntax highlighting — no install, no login.

Launch GraphQL Tester
CORS
Bypass via Proxy
JSON
Syntax Highlighted
History
Request Tracking
Free
No Login Needed

GraphQL API Tester

Enter a GraphQL endpoint URL, write your query or mutation, add optional variables and headers, then click Send Request.

Quick Load Public API
Sending GraphQL request…

Request History

No requests yet. Send your first query above.
Response
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HTTP Status
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Response Time
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Response Size
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GQL Errors

Run the Introspect Schema button to explore the GraphQL schema types and fields.

Why Use Our Tool

Advanced GraphQL Testing Features

Everything you need to test, debug, and explore any GraphQL API — right in your browser.

CORS-Free Server Proxy

All requests are routed through our secure PHP server proxy, completely bypassing browser CORS restrictions — test any GraphQL API without cross-origin errors.

Syntax-Highlighted JSON

Response data is formatted with full JSON syntax highlighting — keys, strings, numbers, booleans, and nulls all color-coded for instant readability.

Variables & Headers Support

Pass dynamic variables as a JSON object and add any custom HTTP headers — Authorization tokens, API keys, Accept-Language, or any custom header your API requires.

Schema Introspection

One-click schema exploration using GraphQL's built-in introspection query. Discover all types, fields, queries, and mutations your API exposes.

Request History

Every request you send is saved in-session. Browse your history, reload previous queries, and compare responses — perfect for iterative API development.

Response Time Metrics

Real-time measurement of API response time in milliseconds, HTTP status code, response size in KB, and GraphQL error count — all displayed instantly.

Real-Time Validation

Instant client-side validation of your endpoint URL, query syntax structure, variables JSON, and headers format — errors are flagged as you type.

Query Snippets & Presets

Load ready-made query templates for queries, mutations, fragments, and introspection in one click. Explore real public APIs like GitHub, SpaceX, and more.

Step by Step

How to Test a GraphQL API Online

Follow these steps to test any GraphQL endpoint in seconds — no tools to install.

1

Enter Endpoint URL

Paste your GraphQL API endpoint URL (e.g. https://api.example.com/graphql) into the endpoint field. Choose POST or GET method.

2

Write Your Query

Type or paste your GraphQL query, mutation, or subscription in the Query editor. Use the snippet buttons to load templates instantly.

3

Add Variables & Headers

Switch to the Variables tab to add dynamic input values as JSON. Switch to Headers to add Authorization tokens or API keys.

4

Send & Analyze

Click Send Request. The tool routes via our server proxy, displays the formatted JSON response, status code, response time, and any GraphQL errors.

5

Export & Save

Copy the response to clipboard or download it as a .txt file. Browse your request history to reload and re-run previous queries anytime.

What is GraphQL? How to Test It & Best Practices

GraphQL is a powerful, open-source query language for APIs, originally developed by Meta (Facebook) in 2012 and publicly released in 2015. Unlike traditional REST APIs — where the server dictates fixed data structures for each endpoint — GraphQL puts the client in control. Developers can request precisely the fields they need in a single request, eliminating both over-fetching (receiving too much data) and under-fetching (requiring multiple round trips to assemble a response). This efficiency makes GraphQL especially valuable for mobile applications and complex frontend architectures.

At its core, GraphQL defines a strongly typed schema that acts as a contract between client and server. Every query is validated against this schema before execution, reducing runtime errors and making APIs self-documenting. Operations come in three forms: queries (read-only data fetching), mutations (creating, updating, or deleting data), and subscriptions (real-time data streams over WebSockets). Combined with the introspection system — which allows clients to discover available types, fields, and operations programmatically — GraphQL offers unmatched developer productivity.

Testing GraphQL APIs is a critical step in any API development lifecycle. Before deploying a query to production, you should verify that the endpoint returns the correct data structure, handles edge cases gracefully, and responds within acceptable time thresholds. Start by using introspection to explore the schema and understand what queries are available. Then craft targeted test queries using realistic variables, and always verify error handling by testing with missing or malformed inputs.

Best practices for GraphQL API testing include: always testing with authentication headers that reflect real user contexts; checking that mutations produce the correct side effects; testing pagination arguments (first, after, last, before); validating that nullable fields are handled gracefully in the client; and monitoring response times to catch N+1 query performance issues. Tools like our online GraphQL tester make this easy — no Postman installation, no configuration — just paste your endpoint and start testing immediately, completely free.

Frequently Asked Questions

GraphQL Tester FAQ

Everything you need to know about testing GraphQL APIs online.

GraphQL is a query language for APIs and a server-side runtime for executing those queries. Unlike REST, GraphQL allows clients to request exactly the data they need in a single request. Developed by Facebook (Meta) and open-sourced in 2015, it is now used by GitHub, Shopify, Twitter, and thousands of other companies worldwide.
Enter your GraphQL endpoint URL above, write your query or mutation in the Query editor, optionally add variables as JSON and custom HTTP headers, then click Send Request. The tool will execute your query via a secure server proxy and display the full JSON response with syntax highlighting, response time, and HTTP status code.
A GraphQL query is a read-only operation — it fetches data from the API without modifying anything. A mutation is a write operation — it creates, updates, or deletes data. Both are sent via HTTP POST by default. The GraphQL specification distinguishes them to help clients communicate intent and to allow servers to enforce different caching and authorization rules.
Click the Headers tab and add: Authorization: Bearer YOUR_TOKEN. This is the most common approach. Some APIs use X-Api-Key or a custom header. Our tool passes all headers through to the API server via our proxy.
Introspection is a built-in GraphQL feature that lets you query the server for its schema — all available types, fields, queries, and mutations. Click the Introspect Schema button above to automatically run the introspection query and display the results in the Schema Explorer tab. This is the foundation of tools like GraphiQL and Apollo Studio.
CORS (Cross-Origin Resource Sharing) is a browser security policy that blocks JavaScript on one domain from requesting resources on another domain unless the target server explicitly allows it. Our tool routes all requests through a server-side PHP proxy, completely bypassing browser CORS restrictions so you can test any API.
Yes. Write your mutation using variable arguments (e.g. mutation CreateUser($name: String!) { createUser(name: $name) { id } }), then switch to the Variables tab and enter your values as JSON (e.g. {"name": "Alice"}). The tool merges variables into the request payload automatically.
Yes, completely free. No registration, login, or subscription is needed. You can send unlimited GraphQL requests at no cost. All data is processed securely via our server proxy and is never stored permanently on our systems.
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