API breaking change tracker: how to find out what breaks *your* integration before prod does
The question
You integrate five or more vendor APIs. Deprecation notices arrive in changelogs you don't read, emails that hit the wrong inbox, or not at all. How do you track breaking changes across vendors — without watching every changelog by hand?
What's actually true
The problem got worse recently, and there are named examples:
- OpenAI's Assistants API hard-shutdown is scheduled for August 2026. Anyone who built on it has a hard migration deadline, not a soft one.
- Google Photos API changes produced a wave of 403 errors for existing integrations — the failure mode where you learn about the change from your error logs.
The tooling landscape reflects how real this is: a slot that was essentially empty a year ago now has multiple entrants — FlareCanary ($19/mo), SpecFlag, SpecShield, oasdiff Pro — plus API Drift Alert at $149/mo. All of them sell monitoring subscriptions. At the enterprise end, bundled third-party risk platforms like UpGuard start around $1,750/mo.
But there's a gap every one of these shares: a generic monitor tells you the vendor changed something. It doesn't tell you whether the change touches the three endpoints you actually call. A firehose of every change across every vendor is almost as useless as no feed — the work of triaging it lands back on you.
How to check it yourself
For any vendor with a public OpenAPI spec, you can build a first pass today:
- Collect spec URLs for each vendor API you depend on. Many vendors publish OpenAPI/Swagger documents publicly.
- Write down your endpoint manifest — the actual paths and methods your code calls. (Grep your codebase for the client calls; this list is shorter than you think and more valuable than any dashboard.)
- Diff the spec over time. Open-source tools like oasdiff can compare two spec versions and flag breaking changes. Snapshot specs on a schedule and diff against your last snapshot.
- Intersect the diff with your manifest. This is the step that turns noise into signal: a removed endpoint you never call is trivia; a changed parameter on an endpoint you call in production is a work item.
- For history you didn't capture, the Wayback Machine's public API holds past states of many spec and documentation pages — you can reconstruct roughly what changed over the past year.
That's a real afternoon of scripting per vendor, plus maintenance — which is exactly why the monitor subscriptions exist.
The one-shot alternative
VendorWatch does the above as a $29 audit: you declare your vendors and the endpoints you call, and get one report of the deprecations and removals touching your integration (plus legal and pricing-page changes over 12 months), every finding linked to the spec or page state we observed. No subscription required to get the baseline.