How to Keep OpenAPI Documents Up to Date with Manual Documentation

So, you’ve got your fancy OpenAPI docs set up, your API is humming along, and everything looks perfect. But give it a few months (or even weeks), and suddenly… the docs are outdated.

Endpoints change. Parameters shift. That one developer swore they’d update the docs but totally didn’t. Now, you’re left with a sad, outdated OpenAPI file that barely resembles reality.

Let’s fix that.

Why Do OpenAPI Docs Go Out of Date?

There are a few common reasons why OpenAPI docs fall behind:

• Developers are busy – Code comes first; docs are an afterthought.
• Lack of automation – If updates aren’t part of the workflow, they get ignored.
• API evolution – APIs change faster than people remember to update the docs.
• No accountability – Nobody “owns” the documentation process.
• Manual updates are painful – Updating YAML or JSON manually is no one’s favorite pastime.

But don’t worry! There are ways to keep your OpenAPI docs fresh without making it a full-time job.

🔥 The Secret to Up-to-Date OpenAPI Docs: A Process

Keeping OpenAPI documentation updated manually isn’t impossible—it just requires a good process. Here’s how:

1. Make Docs Part of the Development Workflow

If updating OpenAPI docs isn’t a required step, it won’t happen. Period. Here’s how to make it a habit:

• Pull Requests Must Include API Doc Updates
  Every API change should come with an OpenAPI update. Make it a rule: No API change gets merged without a matching documentation update.

• Code Reviews Must Check OpenAPI Docs
  Whoever reviews the PR should also review the OpenAPI spec. If the docs are missing, reject the PR.

• Track OpenAPI Updates in Git
  Keep your OpenAPI file in version control (Git, SVN, etc.) so changes are tracked just like code.

2. Use OpenAPI Comments in Code (When Possible)

Some frameworks allow you to annotate API endpoints directly in code, making updates automatic.

Example: Python (FastAPI)

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from fastapi import FastAPI

app = FastAPI()

@app.get("/users/{user_id}", summary="Get user by ID", description="Returns user details.")
def get_user(user_id: int):
    return {"user_id": user_id, "name": "John Doe"}

Since FastAPI auto-generates OpenAPI docs, there’s no excuse for outdated documentation.

Example: Node.js (Express + JSDoc)

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/**
 * @openapi
 * /users/{id}:
 *   get:
 *     summary: Get user by ID
 *     description: Returns user details
 *     parameters:
 *       - name: id
 *         in: path
 *         required: true
 *         schema:
 *           type: integer
 *     responses:
 *       200:
 *         description: Successful response
 */
app.get('/users/:id', (req, res) => {
  res.json({ userId: req.params.id, name: "John Doe" });
});

This method ensures code and docs stay in sync.

3. Schedule Regular OpenAPI Audits

Even with good habits, things slip through the cracks. That’s why you should schedule manual documentation audits every few weeks.

Suggested Audit Checklist:

✔ Compare OpenAPI docs to actual API behavior
✔ Test API calls and ensure responses match the documentation
✔ Verify all endpoints are still active
✔ Check for missing query parameters, headers, or body fields
✔ Confirm descriptions make sense to external users

This can be done every sprint or at the start of each month.

4. Use API Linting & Validation Tools

If you don’t trust humans to update OpenAPI docs, let robots help.

Here are some tools to validate your OpenAPI docs and catch errors:

• Spectral – Lint your OpenAPI docs for missing or incorrect fields.

  1 2	npm install -g @stoplight/spectral spectral lint openapi.yaml

• Swagger Editor – Quickly test and validate OpenAPI JSON/YAML files.
  Run it locally:

  1	docker run -p 8080:8080 swaggerapi/swagger-editor

• Redocly CLI – Lint and validate OpenAPI for Redoc users.

  1 2	npm install -g @redocly/cli redocly lint openapi.yaml

Set up these tools in your CI/CD pipeline to catch issues before merging changes.

5. Use a Changelog for API Changes

A simple changelog helps track API changes and keeps documentation transparent.

Example Changelog Format:

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## [1.2.0] - 2023-06-10
### Added
- New endpoint `/orders/{id}/refund`
- `order_status` query parameter for `/orders`

### Changed
- `/users/{id}` now returns `last_login` timestamp

### Removed
- Deprecated `/v1/orders` (use `/v2/orders` instead)

You can store the changelog in:

✅ API Docs (changelog.md)
✅ OpenAPI Spec (openapi.yaml)
✅ Git Commit Messages (CHANGELOG.md)

6. Assign Documentation Ownership

If “everyone” owns API documentation, nobody owns it. Assign specific people to review and maintain OpenAPI files.

Who Can Own OpenAPI Documentation?

• Tech leads – Ensure docs are accurate before releases.
• Backend devs – Update OpenAPI whenever API changes.
• API documentation team – Review docs from a user perspective.

Even better, rotate ownership each sprint to keep everyone accountable.

Manual Documentation Advice