DNS Medic — jstoneky

The Problem
NextDNS, Pi-hole, and other DNS-level blockers work great for privacy, but they can cause subtle breakage on websites. A feature flag service gets blocked, and suddenly an inventory page won't load. An auth provider is blocked, and login silently fails. A payment processor is blocked, and checkout never completes. You reload the page six times wondering what's wrong, never knowing DNS was the culprit.

This extension makes that visible — and tells you exactly what's at stake.

How It Works
Monitors network errors on every tab using the browser's webRequest API
Identifies DNS-block signatures — certificate issuer failures, name resolution errors, and other patterns that indicate a DNS-level block (not a server error or timeout)
Classifies every blocked domain against a database of 492 known services across 13 categories, grouped by how likely they are to break site functionality:
🔴 High — Feature flags, authentication, payment processors, search APIs, core CDNs, CAPTCHA. These break sites.
🟡 Medium — Support chat, video players, maps, image CDNs, error monitoring, e-commerce. May affect functionality depending on the site.
🟢 Low — Pure analytics and advertising. Almost never affects how a site works.
Shows a functional impact badge on every blocked domain — so you know at a glance what breaks, not just that something broke
Attributes the block to a specific blocklist — works for both NextDNS (from the logs API) and Pi-hole v6 (via the gravity search API, with pretty names for 30+ common lists)
Confirms DNS routing — a live status chip in the header shows whether your browser is actually sending DNS through your selected provider (green = active, red = not routing)
Unknown domains fall back to Medium — worth reviewing, but not necessarily critical
Badge updates on the extension icon: count of blocked domains, red = high-risk detected