Chrome’s Local Network Access Prompt: What Breaks for Localhost Dev (and When a Tunnel Is the Wrong Fix)
If a hosted frontend suddenly can’t reach your localhost:8080 API in Chrome, you have almost certainly met Local Network Access (LNA) . Since Chrome 142, requests from public websites to local and loopback addresses sit behind a permission prompt. Chrome 156 reached Stable on October 20, 2026. It removed the temporary enterprise opt-out policy, so managed browsers can no longer downgrade these blocks to DevTools warnings. This guide covers which developer setups break, how to read the confusing errors, why a tunnel URL makes the problem vanish, and why that is often the wrong fix. TL;DR LNA gates requests from a public page to a local or loopback destination behind a per-site permission. If a user clicks Block, the connection stays broken until they reset the permission. Hosted frontends, third-party dashboards and iframes that call your dev server break. A localhost page calling localhost does not. Chrome 156 removes the LocalNetworkAccessRestrictionsTemporaryOptOut policy....
