PRACTICAL FIELD GUIDE
Fetch resolved, but the API returned an error
A fetch promise can resolve for an HTTP error response. Application code must check the response status before treating parsed JSON as successful record data.
MCPBackend editorial team · · Examples are illustrative
Put it into practice
- Inspect response.ok or the status before using the payload.
- Read the API's error code and message and map expected failures to useful UI states.
- Handle network failures separately because they may not provide an HTTP response at all.
What this looks like
ILLUSTRATIVE EXAMPLE
A request returns 403 with a JSON error object, but the UI tries to render it as a list. The request completed; the intended operation did not.
A boundary to keep clear
Do not show a success notification just because the network call resolved without throwing.
MCPBackend context
Use get_project_api or the dashboard's generated OpenAPI contract for your project's exact data-plane routes. Machine keys and end-user tokens have different access models. Treat error status and JSON code together, keep credentials out of URLs, and test against disposable records before changing real data.
Take the next step
Inspect the current project contract, try the change with disposable data, and verify the result through the same credentials your app will use. Record the expected response and one denied-access case before release.
Sources and further reading
These references explain the underlying protocols and design principles. For supported MCPBackend operations and exact request shapes, inspect your project’s generated API contract.