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2026-07-29 16:01
GraphQL

Error Handling

ErrorParseValidateMedium
Try Interactive Demo

What you will learn

  • GraphQL returns 200 with errors array — always check body.errors, not HTTP status
  • Error classifications (VALIDATION, AUTHENTICATION, INTERNAL) belong in the extensions field — never leak raw stack
  • Test partial success: a query with 5 fields can return data for 3 AND errors for 2. Client must handle both arrays

Description

Handle GraphQL errors in response.

Test Scenario

const response = await request.post('/api/graphql', {
  data: { query: '{ invalidField }' }
});
expect(response.status()).toBe(200); // Still 200!
const { errors } = await response.json();
expect(errors).toBeDefined();
expect(errors[0].message).toContain('invalidField');
Endpoint/api/graphql

Testing Tips

  • •GraphQL returns 200 even for errors
  • •Check errors array in response
  • •Partial data with errors possible
// Playwright API Testing - GraphQL
import { test, expect } from '@playwright/test';


test('GraphQL query', async ({ request }) => {
  const response = await request.post('/api/graphql', {
    data: {
      query: `
        query {
          users {
            id
            name
            email
          }
        }
      `
    }
  });


  expect(response.ok()).toBeTruthy();
  const { data } = await response.json();
  expect(data.users).toBeDefined();
});

Challenge ID: graphql-error-handling

2 frameworks available

API Playground

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Endpoint: /api/graphql

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