Maintenance

Know When Browser APIs Will Break Your Site

Browsers constantly remove deprecated APIs. The warnings live in developer consoles — invisible to production monitoring. Deprecation reports give you advance notice to fix issues before they become emergencies.

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The Problem

Deprecated APIs Are Ticking Time Bombs

Browsers evolve constantly. APIs that worked fine for years get marked deprecated, then eventually removed. When that happens, your site breaks — and you find out when users complain, not when you could have fixed it.

The unload event, used by countless analytics and session-saving scripts, is being phased out by Chrome starting March 2025. Synchronous XHR during page dismissal? Already blocked since Chrome 80. document.write()? Deprecated and blocked under certain conditions. These aren't edge cases — they're APIs that millions of sites depend on.

The warnings exist, buried in developer console output. But production sites don't have developer tools open. Your engineering manager doesn't see the yellow triangles accumulating. Technical debt piles up silently until one browser release turns "deprecated" into "removed," and suddenly your checkout flow is broken.

Third-party scripts make it worse. That analytics vendor, that A/B testing tool, that chat widget — they all call browser APIs you never wrote. When their code uses deprecated features, your site breaks. And you won't know until it's too late.

The Solution

Deprecation Reporting: Console Warnings, Delivered to Your Backend

The Deprecation Reporting API is a WICG specification that lets browsers send deprecation warnings to an endpoint you control — the same warnings that appear in developer console, automatically routed to your monitoring infrastructure.

Deprecation reporting is supported by 80% of browsers worldwide — Chrome 69+, Edge 79+, and Opera 56+. When any code on your page calls a deprecated API, the browser generates a report with the feature ID, a human-readable message, and crucially, the anticipatedRemoval date when the API will actually stop working.

Reports include the exact source location: file, line number, and column. You'll know not just that a deprecated API is being used, but where — even if it's buried in minified third-party code. The id field lets you group reports by feature, so you can see how many pages are affected by each deprecation.

Configuration requires just one HTTP header. Point your Reporting-Endpoints header at your endpoint, and browsers start sending deprecation reports automatically. No JavaScript SDK, no build process changes, no runtime overhead.

The Challenge

But Reports Without Context Are Just More Noise

Deprecation reports tell you what's deprecated, but not how urgent it is. Some APIs stay deprecated for a decade — Chrome's webkitStorageInfo was deprecated in 2013 and only removed in 2022. Others move fast: the unload event deprecation has a hard timeline through 2026.

Raw reports don't integrate with your workflow. They arrive as JSON payloads with timestamps and source locations, but no connection to your backlog. Engineering managers need deprecations surfaced as actionable items, not as another log stream to monitor.

Third-party visibility creates its own problem: volume. If your page loads 15 vendor scripts, you might get deprecation reports for code you don't control. You need to distinguish between deprecations in your code (fixable now) and deprecations in vendor code (requires vendor update or replacement).

And without centralized collection, you're flying blind across environments. Deprecation warnings in staging don't help if you're not collecting them. Warnings from real users on production pages reveal usage patterns that local testing misses.

The Answer

The Reporting API Turns Deprecations Into Planned Maintenance

Convert 'sudden breakage' into 'scheduled work' with proactive deprecation monitoring.

Advance Warning with Deadlines: Every deprecation report includes an anticipatedRemoval date when available. Know exactly how long you have to fix each issue — and prioritize accordingly. No more discovering removals after they break production.
Third-Party Script Visibility: See deprecated API usage from vendor scripts running on your pages. Identify which third-party dependencies need updates before their deprecations become your outages.
Prioritized Technical Debt: Group deprecations by feature ID and urgency. Focus on APIs with imminent removal dates first. Give engineering managers visibility into technical debt that's actually accumulating — not just code smells.
Route to Your Workflow: Send deprecation reports to AppSignal, webhooks, or Google Chat. Automatically create backlog items when new deprecations appear. Integrate with the tools your team already uses.

Ready to Monitor Deprecations?

Stop discovering deprecated APIs when they break. Get advance warning and convert sudden failures into planned maintenance.

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