For a small team that needs OpenAPI support plus a changelog / release notes workflow, the best free options are usually the ones that combine:

• easy OpenAPI import
• decent docs hosting
• versioning or release management
• low setup/maintenance burden

Here are the strongest free choices:

1) Stoplight

Best for: polished API docs + API design workflows

Why it stands out

• Imports OpenAPI
• Clean, developer-friendly docs
• Good support for multiple versions
• Can host docs publicly
• Has a nice UI for editing and collaboration

Changelog angle

• Not a dedicated changelog tool, but versioned docs make it easier to publish changes per release
• You can pair it with a simple changelog page in the same docs portal

Limitations

• Free tier may be limited in collaboration/publishing features depending on current plan structure

2) GitBook

Best for: simple docs site + changelog pages for small teams

Why it stands out

• Very easy to use
• Good for product docs, API docs, and changelogs in one place
• Supports embedding or linking OpenAPI-generated content, depending on your workflow
• Great non-technical editing experience

Changelog angle

• Excellent for maintaining a visible changelog page alongside API docs
• Good if you want docs + release notes in one portal

Limitations

• Not the best pure OpenAPI-native docs platform
• API-specific features are weaker than dedicated API doc tools

3) Redocly

Best for: OpenAPI-first docs with strong documentation quality

Why it stands out

• Excellent OpenAPI rendering
• Very clean, professional API docs
• Good versioning support
• Works well if your team stores docs in Git

Changelog angle

• Strong if you publish versioned docs and maintain changelog markdown in your repo
• Good fit for release-driven docs workflows

Limitations

• More technical setup than GitBook
• Free plan/OSS setup may require more self-management

4) Swagger UI / SwaggerHub Community

Best for: minimal setup and broad familiarity

Why it stands out

• Swagger UI is the classic free OpenAPI viewer
• Very easy to get started
• SwaggerHub Community gives some collaborative workflow support

Changelog angle

• Not really a changelog platform
• You’d typically host changelogs separately

Limitations

• Basic docs presentation
• Less polished than newer platforms
• Changelog needs another tool

5) Mintlify

Best for: modern-looking docs with a good developer experience

Why it stands out

• Great UI/UX for API docs
• Supports OpenAPI
• Good for small teams wanting a slick public docs portal

Changelog angle

• Easy to add changelog pages in the same docs site
• Works well if you keep docs and release notes in Git

Limitations

• Some features may be limited on free plans
• Best experience often depends on their hosted workflow

6) ReadMe

Best for: API docs + changelog if you can fit within free limits

Why it stands out

• Strong API documentation experience
• Can handle changelog/release note style content
• Popular among API-focused teams

Changelog angle

• Good support for release notes and docs organization

Limitations

• Free tier is usually quite limited
• Often becomes paid as soon as team needs grow

---

Best picks by use case

If you want the best balance of OpenAPI + changelog:

Redocly or Stoplight

If you want docs and changelog in one simple team wiki:

GitBook

If you want the most polished modern docs site:

Mintlify

If you want the simplest free OpenAPI viewer:

Swagger UI

---

My practical recommendation for a small team

If you want free + easy + OpenAPI + changelog with minimal pain:

1. GitBook if you want non-technical editing and a docs/changelog portal
2. Stoplight if OpenAPI accuracy and API design matter most
3. Redocly if your team is comfortable working from Git and wants the best OpenAPI presentation

---

One important note about changelogs

Most API doc platforms are not truly changelog systems. A good setup is often:

• OpenAPI docs platform for reference docs
• Markdown changelog page in the same site
• optional Git-based release notes in your repo

That usually works better than relying on a docs tool to do everything.

If you want, I can also give you:

• a comparison table
• the best free/open-source options only
• or a recommended stack for GitHub + OpenAPI + changelog