REST API and Web Service Monitoring

Monitor the availability and performance of your APIs in real-time.

APIs have become the backbone of modern software architecture. Microservices, mobile apps, third-party integrations: everything relies on APIs that must function 24/7. An unavailable API doesn't just return an error - it can paralyze an entire chain of dependent services.

API monitoring goes beyond simple availability checks. It's about ensuring the API returns the right data, in acceptable time, with working authentication. An endpoint returning "200 OK" but corrupted data is just as problematic as a completely down endpoint.

MoniTao offers comprehensive API monitoring: HTTP code verification, response time measurement, JSON content validation, Bearer authentication support. You're alerted instantly if something goes wrong, before your users or dependent services are impacted.

The Challenges of API Monitoring

Effectively monitoring an API presents specific challenges:

  • Hidden dependencies: Your APIs often depend on other services: database, cache, external services. A cascade problem can be hard to isolate without proper monitoring.
  • Progressive degradation: An API can degrade progressively: increasing response times, intermittent errors. Without metric tracking, you only detect the problem at collapse.
  • Complex authentication: Modern APIs use OAuth, JWT, API keys. Monitoring must support these mechanisms to test protected endpoints.
  • Content validation: A 200 code doesn't mean everything is fine. The API might return an error in the response body, or incomplete data.

Supported API Types

MoniTao can monitor all types of web APIs:

  • REST API: The most common standard. Support for GET, HEAD methods. HTTP code verification, response time and optionally JSON content.
  • GraphQL Endpoints: Monitor your GraphQL endpoints by checking the server responds correctly to introspection queries or specific queries.
  • Webhooks: Use MoniTao heartbeat as a webhook destination to verify your webhooks are being triggered properly.
  • SOAP/Legacy APIs: SOAP and legacy APIs can be monitored via their HTTP endpoints. Configure appropriate headers (Content-Type, SOAPAction).

Checkpoints

At each check, MoniTao verifies several aspects:

  • HTTP Code: Verification that the return code is in the expected range (2xx by default). Alerts on 4xx, 5xx or unexpected codes.
  • Response Time: Precise response time measurement in milliseconds. Performance history to detect degradations.
  • Content Validation: Search for a specific string in the response. Perfect for checking a JSON field exists or an error message is absent.
  • SSL Certificate: For HTTPS endpoints, SSL certificate validity verification and alert before expiration.

API Configuration Example

Here's how to configure monitoring for a REST API with authentication:

# API monitor configuration in MoniTao

URL: https://api.example.com/v1/health
Method: GET

# Authentication headers
Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
Content-Type: application/json
Accept: application/json

# Content validation (optional)
Search for: "status": "healthy"

# Alerts
Timeout: 10 seconds
Interval: 60 seconds
Alert if: HTTP Code >= 400 OR content not found

This configuration checks that the health check endpoint returns a 2xx code, responds within 10 seconds, and the response contains "status": "healthy". Any anomaly triggers an alert.

Key Features

MoniTao includes advanced features for API monitoring:

  • Custom headers: Add all necessary headers: Authorization, API-Key, Content-Type, etc. Full support for Bearer and API Key authentication.
  • Double verification: Before alerting, MoniTao performs a second check to eliminate false positives due to temporary network issues.
  • Performance history: Response time graphs over 24h/7d/30d. Identify trends and progressive degradations.
  • Multi-channel alerts: Email, SMS, Slack, webhook: choose the channel adapted to each monitored API's criticality.

Checklist: Configure API Monitoring

  • Identify critical endpoints to monitor (health, authentication, core features)
  • Configure necessary authentication headers
  • Define validation criteria (HTTP code, content)
  • Set check interval according to criticality
  • Configure appropriate alert channels
  • Test configuration by simulating an outage

Frequently Asked Questions

Can I monitor a private API (not publicly accessible)?

MoniTao monitors APIs accessible via Internet. For internal/private APIs, use the heartbeat system: your server sends a ping to MoniTao after each successful execution.

How to configure Bearer/JWT authentication?

In monitor settings, add a custom header: "Authorization: Bearer your_token". The token will be sent with each check. Remember to use a long-lived token.

Can MoniTao send POST requests with a body?

Currently, MoniTao performs GET and HEAD requests. To test POST endpoints, create a GET health check endpoint that validates your API is working properly.

Is the API tested from multiple geographic locations?

Checks are performed from our servers in Europe. Double verification confirms alerts to eliminate network-related false positives.

How to monitor an API with rate limiting?

Adjust the check interval to stay under rate limits. A 5-minute interval instead of 1 minute reduces requests by 80%.

Can I validate the JSON format of the response?

MoniTao allows searching for a string in the response. To check a JSON field exists, search for '"field_name":'. For complete JSON validation, use a dedicated health check endpoint.

Conclusion

API monitoring is no longer optional in modern architecture. Every critical API must be monitored to ensure the availability and performance of your services. MoniTao simplifies this monitoring with intuitive configuration and reliable alerts.

Start by identifying your most critical APIs: authentication endpoints, payment APIs, essential third-party integrations. Configure their monitoring in MoniTao and sleep soundly.

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