Current limitations, known bugs, and planned improvements for Mock API Builder. We're transparent about what's not working perfectly yet.
These are by-design limitations of the mock API platform. They're not bugs, but important constraints to be aware of.
What this means: Each API request generates fresh data. If you POST a new user, it won't appear in subsequent GET requests.
Workaround: Use seeded data to get consistent results. Stateful mocking may be added in a future release.
What this means: You can't request more than 100 records at once using ?limit=100.
Workaround: Use pagination with multiple requests. This is actually a best practice for real APIs too.
What this means: You can't fetch related data in a single request (e.g., users with their posts).
Workaround: Make separate requests for related data and combine on the client side.
What this means: Free accounts are limited to 60 requests/minute and 5,000 requests/day.
Workaround: Implement caching on your frontend, or contact us if you need higher limits for a specific use case.
See our Rate Limiting Guide for best practices.
Known bugs that are currently being investigated or fixed. We appreciate your patience.
When importing an OpenAPI spec, fields marked as optional (not in the required array) are sometimes incorrectly treated as required.
Workaround: Manually edit the generated schema to mark fields as optional after import.
The visual schema editor becomes slow and unresponsive when editing schemas with more than 50 fields.
Workaround: Use the JSON editor mode instead of the visual editor for large schemas. It's much faster.
When using date.future, occasionally a past date is generated due to timezone conversion issues.
Workaround: Happens rarely (~5% of requests). You can filter dates on the client side or accept the occasional anomaly.
Features and fixes we're planning to implement. Want to influence our roadmap? Check out Feature Requests.
Ability to create GraphQL endpoints alongside REST APIs. Define schemas, queries, mutations, and subscriptions.
Configure webhooks to send POST requests to external URLs when certain events occur (new data created, updated, etc.).
Support for comparison operators in query parameters: ?price_gt=100, ?date_gte=2025-01-01, etc.
Share projects with team members, assign roles (viewer, editor, admin), and collaborate on API design.
Mock API Builder is tested and supported on the following browsers:
Note: Internet Explorer is not supported. Some features may not work properly on older browsers.