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API Stability Scores

Picking a vendor is the easy part. Keeping the integration working three years later is the hard part. This page grades 15+ developer APIs on three things: how often they ship breaking changes, how much warning they give, and whether their versioning scheme lets you stay on a known-good version.

Methodology

Each provider is reviewed against three measurable signals:

  • Breaking changes per year — counted against the public stable API, not beta or preview surfaces. Migration-codemod-only changes count as half.
  • Deprecation window (days) — calendar days between a public deprecation notice and the date the old behavior stops working. 365+ days is considered industry-best.
  • Versioning policy — whether you can pin a specific API revision (dated headers, semver major) versus being forced onto whatever the vendor is shipping today.

Overall A-F is a single integrated grade. The notes column explains the specific incident or policy that drove the rating. Sources are official changelogs, blog posts, and migration guides linked from each vendor's documentation.

Why this matters

A high-traffic API integration is a multi-year commitment. The hidden cost of a low-stability vendor is not the migration sprint itself — it is the recurring attention tax on every roadmap planning cycle. An A-rated provider lets you forget they exist for years. A D-rated provider takes up a slot in your team's maintenance schedule every quarter.

What this score doesn't measure

  • SDK churn — the JavaScript wrapper around the API often breaks more often than the API itself. See /sdk-quality.
  • Pricing model changes. See /pricing-traps.
  • Outage frequency. See /outages.

Rankings