Treat HTTP failures as product behavior

Developer bridge: networking applied to APIs
Original starter lesson / sources checked 2026-09-30

Name resolution, transport, and application responses are separate failure points. A network exception differs from an HTTP error response.

With fetch, inspect response.ok or the status before using the body. A 404 response does not automatically reject the promise.

Show a recoverable user message and retain useful diagnostic context without exposing private data.

Hands-on lab

Build a local request demo with success, 404, and a network failure.
Show an intentional user message for each case and record only safe diagnostic fields.

Put the lesson to work

Original exam-style practice. Choose the best answer for the stated scenario.

1. fetch resolves with a 404 response. What should code do before accepting the body?

Assume resolution means successCheck response.ok or statusDelete the request codeDisable all errors

2. Which field is useful in a diagnostic error event without including a private payload?

The user's passwordEvery request bodyA request correlation IDThe service secret key

Go deeper

Official CompTIA scope and exam information WWADD Move: fetch JSON with error handling

Independent practice aligned to selected topics. No endorsement, actual exam items, or pass guarantee. Verify your exam version and use the full official objectives for complete preparation.