What changed when it shipped

Two questions that are really one. What changed in the contract, and what changed in reality when it went out.

These three stopped when v12 shipped; this one is new.

That sentence is the difference between a diff and an explanation, and it is what this page produces.

The contract half

It compares the compiled operations, not the document's bytes.

A reordered key, a rewritten description, a $ref pulled out into components - all noise, none of it changing what your traffic is held to. What you get instead is the list of things that will now be checked and were not, in the words you would use:

• createRefund added
• legacyThing removed - traffic to it is now undeclared: still forwarded, in both modes, and counted rather than checked
• listOrders changed
  • query/limit is now required
  • new parameter query/cursor
  • 429 application/json is now checked
  • now requires authentication

"The response schema changed" is true and useless. "429 is now checked and was not" is something to act on.

If the two documents differ but the compiled contract does not, the page says exactly that rather than showing you an empty list and letting you wonder.

The reality half

This comes almost free, because a fingerprint already carries the spec version it happened under. The same failure under v11 and v12 is two fingerprints, so the answer is a set difference:

• Stopped at #12 - seen under the old version, never under the new one.
• Started at #12 - never seen under the old one. If you are looking for what a deploy broke, it is here.
• Carried over - seen under both. The deploy neither caused nor fixed these.

When it will not pretend

If no drift was ever reported under one side of the boundary, the page says so before showing you anything. With nothing observed on one side, "fixed" cannot be told apart from "never seen", and presenting arithmetic as evidence would be worse than presenting nothing.

The same caution applies to a version that ran for ten minutes at 3am on a Sunday. Look at coverage for that period before drawing a conclusion from a quiet column.

From a terminal

apip specs diff 42            # published, against what it replaced
apip specs diff 42 11 12      # two versions by id