When we build an API, we’re not just writing code. We’re telling a story. That story must be clear, detailed, and easy to follow. Without good documentation, our API is a mystery. Users can’t use it, teams can’t support it, and mistakes happen fast.
Documentation is not an afterthought. It is part of our design. It guides developers, architects, and business teams. It builds trust and speeds up adoption.
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Let’s learn why documentation matters and how to do it well with MuleSoft tools like RAML and Anypoint Exchange.
But what are those common documentation elements all our APIs should include? Here is my top 7:
Documentation is not an afterthought. It is part of our design. It guides developers, architects, and business teams. It builds trust and speeds up adoption.
.
Let’s learn why documentation matters and how to do it well with MuleSoft tools like RAML and Anypoint Exchange.
Ways to add documentation to our APIs
We use RAML (RESTful API Modeling Language) to design APIs. RAML lets us write docs as part of the spec. That means the docs live with the code. They stay updated as the API changes. Here are a few ways RAML helps us write strong documentation within the API spec:- Descriptions – We can add descriptions to resources, methods, parameters, and responses.
- Annotations – These let us define custom metadata, like internal notes, usage tips or custom notes for governance or tooling
- Documentation Sections – RAML supports markdown sections inside the API spec. These show up clearly in Anypoint Exchange when we include full sections like “Overview,” “Authentication,” or “Error Handling” using
documentation:blocks. - Examples and Types: Show sample requests and responses right inside the RAML.
- Traits and Resource Types: Define shared logic and explain it once. This keeps things clear and consistent.
- Markdown pages for guides and tutorials
- Visual API consoles or API notebooks for interactive testing
- Linked files like Postman collections or PDFs
- Categories and tags for the metadata of the asset.
7 Documentation Sections you should always include for Standardization
Clear, consistent documentation is the foundation of a good API experience. In addition, as a best practice the documentation of our APIs should be standardize. When every API in our organization follows the same structure, developers know what to expect. They can find what they need quickly, without guessing. That’s why it’s also very important to define the common documentation elements that all the APIs in our organization should have. This will greatly reduce the support questions, speed up onboarding, and help teams across projects work in sync. It creates a shared language, so we can build and scale with confidence.But what are those common documentation elements all our APIs should include? Here is my top 7:
1. Welcome or Overview
This is the front door. It explains what the API does and why it exists. It shows who should use it and what problems it solves. So, for every API we publish we should always include in this section:- A one-paragraph summary
- Key use cases
- Audience (internal, external, partner)
- API lifecycle status (Beta, GA, Deprecated)
- Where it belongs in the Application Network of your organization, what part of the API led connectivity of a whole use case this API covers
2. How to consume this API
Our API will be first published to Exchange and right after API manager will apply some policies to control, secure and govern how this API can be consumed. All of this should be clearly explained in a section that includes:- How to request access - If we need to register our client app for client id/secret, request a token to include in our API calls or if it is simply publicly available
- Usage limits - We need to inform if there’s any throttling policy, spike control or if there are different consumption Tiers
- Maintenance - In here we let the API consumer know the validity of their credentials, how to renew them and where to find additional documentation, tutorials, examples...
3. Security and Authentication Guide
Trust begins with clarity. This page explains:- Security Perimeter - Explains if this API is public or private. If private it explain also the internal networks/locations from which this API can be consumed
- If the API requires mTLS it should explain how to get the certificates
- What authentication method the API uses (OAuth 2.0, basic auth, client ID/secret)
- Where and how to get credentials
- Any roles or scopes needed
curl or HTTP calls. Keep sensitive info out of public view. 4. Error Handling
APIs fail. We must explain how they fail and what to do. For that, in this section of our documentation we should include:- Standard error format
- HTTP status codes and meanings
- Common error scenarios
- Tips for troubleshooting
5. Environment & Testing
This is the launchpad. In here, we should list:- All environments (Sandbox, QA, Prod)
- URLs for each
- Any differences between them
- Mock or test tools, like Postman collections or test credentials
6. Change Log
APIs evolve. Users need to know what changed and when. For that, in this section of our documentation we should include:
- Version history
- Dates and changes for each release
- Breaking vs non-breaking updates
- Deprecation notices
7. Support
When things go wrong, we must be ready. This page explains:
- How to raise a ticket
- Links to our support portal
- Contact details for urgent help
- Expected response times
- FAQs