Troubleshooting & Tips

Groups Are Missing

• Make sure every asset includes dev-src/dev-href or test-src/test-href. Devmode ignores tags that only declare a src/href.
• Groups detected inside iframes must live on the same origin as the parent frame. Cross-origin frames are not accessible.
• If you just added markup, reload the page once so the content script can rescan and send the mappings to the service worker.

Environment Changes Do Nothing

• Verify that Auto-reload on change is enabled or reload manually after toggling a group. Redirect rules only apply to new navigations.
• Check DevTools ? Network. Requests should show a (307 Internal Redirect) entry pointing to the DEV/TEST URL.
• Some early, parser-blocking scripts may begin loading before Devmode swaps them. Prefer defer/async or rely on the redirected request occurring on the second load.

Browser Blocks the Alternate URL

• Review the page’s Content Security Policy. If CSP forbids the DEV/TEST host, Chrome blocks the redirected request.
• Mixed content rules apply: HTTPS pages cannot load http:// DEV assets unless you enable insecure content for that origin.

Storage or Rule Limits

• Chrome caps dynamic DNR rules per extension (5,000). If you script hundreds of unique URLs, prune unused mappings via chrome.storage.local or split large origins into smaller groups.
• Clearing site data for the origin will wipe stored environments and mappings; Devmode will rediscover them on the next visit.

Debugging Tips

• Open chrome://extensions, enable Service worker console logging, and watch for warnings while toggling environments.
• In the page console, run chrome.declarativeNetRequest.getDynamicRules() to confirm the redirect entries Devmode created.
• Temporarily disable other extensions that manipulate network requests to rule out conflicts.

Still stuck? Review the FAQ or contact the Sygnal team with reproduction steps, a HAR file, and screenshots of your markup.