API Monitoring & Response Tracking
Monitor REST API endpoints for changes in response payloads, status codes, and headers. OnChange detects diffs in JSON responses and alerts you the moment an API behaves differently.
API Monitoring Features
JSON Diff Detection
OnChange parses JSON responses and generates structured diffs showing exactly which fields changed, were added, or removed. No more guessing what is different.
Custom Headers & Auth
Configure custom request headers, API keys, Bearer tokens, and basic authentication. Monitor protected endpoints that require credentials.
Status Code Monitoring
Track HTTP status codes alongside response body changes. Get alerted when an endpoint starts returning errors or unexpected status codes.
Flexible Scheduling
Check endpoints from every 10 seconds to daily intervals. Match your monitoring frequency to the criticality of each API.
Response Comparison
Side-by-side comparison of previous and current API responses. Quickly identify additions, removals, and modifications in the response payload.
Multiple HTTP Methods
Monitor GET, POST, PUT, and other HTTP methods. Send request bodies for POST/PUT endpoints to test specific API behaviors.
Common API Monitoring Scenarios
Third-Party API Changes
APIs you depend on can change without notice. Monitor the response structure of third-party APIs to catch breaking changes before they affect your production systems. When a field is removed, renamed, or changes type, you know immediately.
Public Data Feed Tracking
Monitor government data feeds, exchange rates, stock prices, or any public API that exposes data you rely on. Track specific JSON fields and get alerted when values change beyond a threshold. Build a historical record of data changes over time.
Internal API Health Checks
Go beyond simple uptime monitoring. Track the actual content of health check endpoints to ensure your microservices are not just responding, but responding correctly. Detect when a service starts returning degraded responses or stale data.
Competitor API Surveillance
If competitors expose public APIs (product feeds, pricing endpoints, status pages), monitor them for changes. Track when they add new endpoints, modify response formats, or update rate limiting. Gain insights into their platform evolution.
Setting Up API Monitoring
Enter the API endpoint URL
Provide the full URL of the REST endpoint you want to monitor. OnChange supports HTTP and HTTPS endpoints.
Configure request parameters
Set the HTTP method (GET, POST, etc.), add custom headers, configure authentication tokens, and specify a request body if needed.
Set monitoring frequency
Choose a check interval that matches the API's importance. Critical endpoints can be checked every 10 seconds; less urgent ones hourly or daily.
Configure change alerts
Set up notifications via email, Slack, Discord, or webhooks. You can filter alerts to only trigger on specific types of changes.
Review diffs and history
When changes are detected, review structured JSON diffs in the dashboard. The full change history is stored and accessible via the OnChange API.
Benefits for Development Teams
Related Resources
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