Keeping Docs in Sync: Regenerating on Every Spec Change

Quick answer: Documentation stays accurate only when regeneration is wired into the same pipeline that changes the spec, not when it depends on a person remembering to rebuild the docs after a merge. The reliable setup treats the OpenAPI description as the single source of truth, generates the reference docs on every commit, and fails the build if the spec is invalid or the generated output cannot be produced, so a published page can never quietly describe an older API. The trade-off is that prose that cannot be derived from the spec must live in versioned, reviewed files alongside it, so the narrative and the generated reference evolve together. If you rely on a documentation platform that is updated by hand or through a separate manual deploy, the docs will drift, and the team will discover it from a customer who followed a page describing a field that no longer exists.

Teams usually start with good intentions and a polished documentation site, but the reference section is only as current as the last time someone synchronized it. In a fast-moving codebase, fields are renamed, endpoints are deprecated, and enum values change, and each of those is a normal pull request against the spec. Whether the docs reflect that change depends on the process. When the docs are a separate artifact, updated by a different person through a different tool, the link is weak and drift is the default state. Making the spec the source of truth and the documentation a generated artifact removes the manual step: the same commit that changes the contract triggers the rebuild, and review of the pull request shows both the spec change and the documentation impact.

Manual doc updates versus automated regeneration

The difference is where correctness is enforced.

The invalid spec row matters because a generation step doubles as a validation gate; if the spec does not parse or violates a lint rule, the build stops rather than producing a broken documentation site.

Wire generation into CI

On every change, validate the spec, generate the reference, and publish the output only from the pipeline, so no manual build can reach the hosting environment.

# pipeline step: validate, then generate, then deploy
npx @stoplight/spectral-cli lint openapi.yaml
npx redocly build-docs openapi.yaml --output dist/reference.html

# deploy only the generated artifact from CI
# a hand-edited reference cannot overwrite the generated one

Generating from a clean checkout in CI also guarantees the output is reproducible and does not depend on a particular developer's machine, which removes the "works when I build it" class of documentation failures.

Keep hand-written prose beside the spec

Not everything is derivable from a schema; guides, concepts, and migration notes are prose. Keep those as versioned Markdown in the same repository and review them in the same pull requests, so a change that alters behavior can update the narrative in the same change.

docs/
  openapi.yaml                 # source of truth
  guides/
    authentication.md          # reviewed prose
    migrating-from-v1.md
  generated/
    reference.html             # CI output, never hand-edited

A useful guard is to make the generated directory write-protected from manual edits and have CI overwrite it, so the boundary between generated and authored content is enforced rather than merely documented. Preview builds for each pull request let reviewers see the rendered documentation before merge, which catches confusing wording even when the spec itself is valid.

Verify the published site matches the release

Add a post-deploy check that confirms the live docs reference the current spec version, for example by asserting the generated version identifier or a newly added field appears on the page. The contract and the documentation should be versioned together, so a release tag maps to exactly one spec and one generated site rather than leaving the docs to be reconciled later.

The practical rule is to make documentation a build product of the spec, regenerated and validated on every commit, with hand-written guides kept under version control beside it. The cost is discipline: prose must be reviewed in the same process and the generated output must not be hand-edited. Relying on a manually updated platform makes drift inevitable, because correctness then depends on memory rather than the pipeline. Tie the rebuild to the change, and the documentation a customer reads describes the API that actually shipped.

Frequently asked questions

Why do docs drift even when the team is careful?

Because a separate manual update relies on someone remembering each time. When the spec and the docs are updated through different processes, the docs describe the last manual sync, not the current API.

How does CI stop stale documentation?

It regenerates the reference from the spec on every commit and only deploys the generated artifact, so a published page always reflects the current contract or the build fails.

What about guides and conceptual prose?

Keep them as versioned Markdown in the same repository and review them in the same pull requests, so a behavioral change can update the narrative in the same change.

Should the generated reference ever be hand-edited?

No. Protect the generated directory and let CI overwrite it; manual edits would be lost on the next build and blur the boundary with authored prose.

How do I confirm the live site matches the release?

Add a post-deploy check that a version identifier or a newly added field from the current spec appears on the live page, tying each release to one spec and one generated site.

This is part of the Powerduck vs Mintlify comparison — start there for the full picture of API documentation choices.