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Uptime Monitoring for GraphQL APIs with Vigilmon

#graphql #api #monitoring #devops

GraphQL APIs present unique monitoring challenges compared to REST APIs. A single GraphQL endpoint handles all queries, mutations, and subscriptions - so simple HTTP status code checks tell you less than they would for a REST API. A GraphQL server can return HTTP 200 with an error in the response body, making superficial health checks misleading.

This guide shows you how to set up effective uptime monitoring for GraphQL APIs using Vigilmon.

How GraphQL APIs Differ from REST for Monitoring

In a REST API, different endpoints serve different resources with meaningful HTTP status codes:

GET /api/users     -> 200 OK or 404 Not Found
POST /api/orders   -> 201 Created or 400 Bad Request
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In GraphQL, everything goes through one endpoint, and the response is almost always HTTP 200:

POST /graphql  -> 200 OK (even when queries fail)
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The HTTP 200 response can contain either successful data OR errors:

{"data": {"user": {"id": "1", "name": "Alice"}}}
{"errors": [{"message": "User not found"}]}
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A simple HTTP check on your GraphQL endpoint will report "up" even when your API is broken. This makes keyword assertions essential.

The Right Approach: Monitor with a Health Query

Use a lightweight health check query as your Vigilmon monitor:

query {
  __typename
}
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This returns {"data": {"__typename": "Query"}} if the server is up and processing queries. Use Vigilmon's keyword assertion to check the response body contains __typename.

Even better - add a dedicated health resolver to your schema:

// Apollo Server example
const resolvers = {
  Query: {
    health: async () => {
      await db.raw('SELECT 1');  // validates DB connectivity
      return { status: 'healthy', version: '1.2.0' };
    }
  }
};
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Then send {"query": "{ health { status } }"} and assert the response contains "healthy".

Setting Up Vigilmon for GraphQL APIs

Step 1: Create a POST Monitor

  1. Click New Monitor -> HTTP(S)
  2. Enter your GraphQL endpoint URL: https://api.yourdomain.com/graphql
  3. Set method: POST
  4. Set Content-Type header: application/json
  5. Set request body: {"query": "{ __typename }"}
  6. Set expected status: 200
  7. Add keyword assertion: response body contains __typename

Step 2: Monitor Your REST Health Endpoint Too

Most GraphQL servers also expose a REST /health endpoint for Kubernetes probes. Monitor this separately:

GET https://api.yourdomain.com/health -> 200 OK
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Step 3: Enable Multi-Region Checks

GraphQL APIs often power mobile apps and SPAs with global user bases. Enable multi-region checks to detect regional availability issues.

Step 4: Configure Alert Channels

Connect Vigilmon to your Slack or PagerDuty. Set the failure threshold to 2 consecutive failures to filter transient issues.

Common GraphQL Monitoring Pitfalls

Pitfall 1: Only Checking HTTP Status

A GraphQL server returning {"errors": [...]} with HTTP 200 looks "up" to a basic monitor. Always use keyword assertions to check for successful data in the response.

Pitfall 2: Not Monitoring the Upstream Database

Your GraphQL resolvers depend on your database. A health query that touches the database catches database failures before they cascade to the entire API.

Pitfall 3: Ignoring Introspection Availability

Some production deployments disable introspection for security. If you use an introspection query as your health check, verify it works in your production environment first.

Recommended Vigilmon Configuration for GraphQL APIs

Setting Recommended Value
Method POST
Check interval 1 minute
Timeout 10 seconds
Failure threshold 2 consecutive failures
Keyword assertion Response contains "data":
SSL monitoring Enabled
Regions 3+

Conclusion

GraphQL APIs require a more thoughtful monitoring approach than REST APIs because HTTP 200 does not mean your queries succeed. By using a dedicated health check query and keyword assertions, Vigilmon gives you accurate, reliable uptime monitoring for your GraphQL API.

Start monitoring your GraphQL API with Vigilmon: vigilmon.online - free tier available, no credit card required.

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