Browser Compatibility Detector

• Runtime capability verification

  Validate actual API exposure in the current browser context instead of relying on User-Agent assumptions only.

• Web API compatibility diagnostics

  Cover permissions, clipboard, storage, network, device, and security APIs to identify unsupported and partial states quickly.

• CSS and JavaScript feature checks

  Assess modern features such as Grid, Container Queries, :has(), Nesting, structuredClone, and Promise.any.

• Media and codec capability checks

  Validate WebRTC, MediaRecorder, screen capture, WebCodecs, and common audio/video playback compatibility.

• Browser version reference mapping

  Use MDN Browser Compatibility Data for Chrome, Edge, Firefox, and Safari version planning.

• Copy-ready reporting output

  Reuse results in QA reports, release gates, incident tickets, and long-term compatibility baselines.

1. 1

   Define your browser support matrix first (minimum versions for Chrome, Edge, Firefox, Safari, and mobile browsers).

2. 2

   Run category checks (overview, graphics, media, storage, device, security, CSS/JS) to capture a runtime capability snapshot.

3. 3

   Prioritize Unsupported and Partial items by business impact on login, payment, upload, playback, and core conversion flows.

4. 4

   Use MDN version references to decide when to apply polyfills, fallback implementations, or feature flags.

5. 5

   Re-test on real devices and realistic networks to confirm permission, HTTPS, COOP/COEP, and hardware constraints.

6. 6

   Document and track results in release checklists and regression suites for repeatable compatibility governance.

• Real-time browser capability detection in the current runtime context
• Permission and secure-context diagnostics for geolocation, clipboard, notifications, and isolation-sensitive APIs
• Media and graphics checks for WebGL/WebGPU, WebRTC, recording, codecs, and Picture-in-Picture
• Storage and offline compatibility checks for IndexedDB, Cache API, Service Worker, and storage quota estimation
• Modern CSS compatibility checks for Grid, Container Queries, :has(), Nesting, View Transitions, and viewport units
• Modern JavaScript compatibility checks for ES Modules, dynamic import, structuredClone, BigInt, URLPattern, Intl.Segmenter
• MDN browser version reference for support policy and release planning
• Copyable structured output for QA evidence, release reviews, and incident analysis

If a bug report only includes a raw UA string or server log line, start with User-Agent Parser to normalize the browser, OS, device, and bot context. When the failure happens after a callback, redirect, or deep link, use URL Tools as well, so URL structure and runtime capability evidence stay together in the same investigation.

• Pre-release browser compatibility validation

  Run structured checks against your support matrix before production rollout.

• Browser-specific incident debugging

  Explain failures behind “works in browser A, fails in browser B” reports with capability evidence.

• Critical flow hardening

  Validate compatibility risk for authentication, payments, upload pipelines, and media playback journeys.

• Fallback and polyfill planning

  Map Partial/Unsupported findings to polyfills, alternate APIs, or feature-flag rollouts.

• Media and realtime readiness checks

  Verify WebRTC, recording, codecs, and screen-capture support before enabling communication features.

• Modern CSS adoption risk review

  Estimate support impact before adopting Container Queries, :has(), Nesting, and related features.

• Regression coverage expansion

  Turn high-risk compatibility findings into targeted automated and manual test cases.

• Cross-team decision alignment

  Share one compatibility baseline across frontend, QA, product, and platform teams.

• Define explicit support policy first: target browsers, minimum versions, and mobile constraints.
• Classify findings by impact level: conversion blocker, degraded UX, or acceptable variance.
• Prepare executable fallbacks for high-impact unsupported capabilities.
• Include compatibility verification in pull-request review and pre-release acceptance checklists.
• Always test permission-dependent APIs in both granted and denied states.
• Re-test media and graphics features on different hardware/OS combinations to catch decoder and GPU differences.
• Validate deployment prerequisites for security-sensitive APIs (HTTPS, CSP, COOP/COEP, cross-origin policy).
• Tie remediation priority to user impact and key funnel completion rate.

• Behavior can differ by OS version, hardware profile, enterprise policy, and browser build channel.
• Permission-gated APIs can appear available while remaining unusable until user consent is granted.
• A “supported” status does not guarantee production correctness without parameter, timing, and error-path validation.
• Media and graphics outcomes can change with hardware acceleration, codec packs, and driver stack differences.
• MDN compatibility data is reference context, not proof of runtime availability in your exact page environment.
• Final ship/no-ship decisions still require real-environment end-to-end validation.