Custom REST API Endpoints Returning Errors in Base44
You've created custom API endpoints in your Base44 app to expose data or functionality to external systems, mobile apps, or other services, but the endpoints return errors when called. The errors may be 404 (not found), 500 (server error), or authentication failures.
Custom API endpoints enable Base44 apps to communicate with other systems and are essential for building more complex integrations. When they fail, any external system depending on your Base44 app's API stops working.
The issue may be specific to certain HTTP methods (GET works but POST doesn't), certain endpoints, or certain callers (works from Postman but not from the external system).
Error Messages You Might See
Common Causes
- The API endpoint URL path is different between the editor and the published app
- Authentication requirements are not being met by the calling system
- The endpoint expects a specific request body format that the caller isn't providing
- CORS headers are not set, blocking calls from browser-based clients
- The endpoint logic contains an error that causes a 500 error for certain input data
How to Fix It
Test the endpoint directly using Postman or curl with the exact URL, headers, and body that the external system should be sending. This isolates whether the issue is with the endpoint configuration or the caller.
Check authentication requirements: if the endpoint requires an API key or token, ensure the caller is including it in the correct header format.
For APIs that need to support multiple callers, handle various payload formats, or require complex business logic, a developer can build robust endpoints with proper validation, error handling, and documentation.
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Get HelpFrequently Asked Questions
Why does my Base44 API endpoint return 404?
The endpoint URL may differ between editor and published environments. Verify the exact URL by checking your published app's API settings and test with a tool like Postman.
How do I authenticate calls to my Base44 API endpoints?
Check your API endpoint's authentication settings. You may need to include an API key in the request header. Test the exact headers with Postman to verify what's required.