If you’re responsible for documenting an SDK, or want to be, this guide is designed as a practical resource. A few years ago, I attended Tom Johnson’s API documentation course in San Francisco, which sharpened my thinking around developer audiences, precision, and technical credibility. While API documentation and SDK documentation are not the same discipline, the rigor and empathy required in both are closely related.
Documenting an SDK is not the same as documenting an API — and it’s certainly not the same as writing end-user documentation.
API documentation describes a contract.
User documentation explains workflows.
SDK documentation enables implementation.
When SDK documentation succeeds, developers integrate quickly and confidently. When it fails, they open support tickets, abandon the integration, or choose a competitor.
Here’s what makes SDK documentation work — and what undermines it.
Start with the Fastest Path to Success
The most important metric for SDK documentation is time to first successful call.
Your documentation should begin with:
- Installation instructions
- Authentication setup
- A minimal working example
- Expected output
This is not the place for product positioning. Developers want proof the SDK works.
A strong Quick Start section uses copy-paste-ready code, lists prerequisites clearly, and demonstrates a visible success response. If the quick start fails, trust collapses immediately.
Write Idiomatic, Real Code
SDK documentation must feel native to its language ecosystem.
JavaScript examples should reflect modern async patterns. Python examples should follow common packaging conventions. Error handling should look natural for the language.
Developers instantly recognize artificial examples. If code feels unnatural, confidence drops. SDK documentation must read like it was written by someone who actually builds in that language.
Explain the Abstraction
An SDK exists to simplify an API — but abstraction can create confusion.
Good SDK documentation clarifies:
- What the SDK handles automatically (retries, headers, authentication)
- What developers must configure themselves
- How SDK methods map to underlying API behavior
- Any differences between SDK and raw API capabilities
Developers need a mental model. If they don’t understand what’s happening under the hood, debugging becomes frustrating.
Transparency builds confidence.
Document the Edges, Not Just the Happy Path
Many SDK docs are strong on the ideal example and weak when things go wrong.
High-quality documentation addresses:
- Authentication failures
- Rate limiting
- Pagination
- Timeouts and retries
- Error objects and exception handling
- Version compatibility
Developers rarely struggle with the clean example. They struggle when something breaks.
Anticipating friction is one of the highest-value contributions a technical writer can make.
Maintain Accuracy Through Versioning
SDK documentation often lives in a GitHub repository alongside the code. That means it must evolve with releases.
Common breakdowns include:
- Outdated snippets
- Deprecated methods still documented
- Renamed parameters not updated
- Missing version labels
Broken examples are catastrophic. Documentation should move through pull requests, align with release cycles, and clearly identify breaking changes.
In SDK writing, credibility is technical.
Five Common SDK Documentation Mistakes
These patterns consistently damage developer experience:
1. Over-Explaining Instead of Showing Code
Developers prefer concrete examples over theory. Show working code first, then explain briefly.
2. Copying API Docs into SDK Docs
An SDK is not a duplicate of the API reference. It must contextualize usage within a language.
3. Ignoring Setup Friction
Installation and authentication are the most common failure points. Treat them carefully.
4. Writing Marketing Language
Words like “powerful” and “seamless” don’t help developers ship code. Precision does.
5. Failing to Document Errors
If error handling isn’t clear, debugging becomes guesswork.
Examples of Strong SDK Documentation
Several large technology companies demonstrate high-quality SDK documentation practices:
Stripe – Stripe’s SDK documentation is widely regarded as exemplary. Quick Starts are concise, code samples are idiomatic across languages, and error handling is clearly documented.
Twilio – Twilio provides consistent language-specific SDK guides with structured navigation, clear setup instructions, and runnable examples that anticipate integration challenges.
AWS (e.g., AWS SDK for JavaScript) – AWS SDK documentation is comprehensive and tightly versioned. Examples reflect real-world patterns, and method-level documentation aligns closely with service behavior.
In each case, documentation prioritizes implementation clarity, language fluency, and completeness.
The Core Principle
The goal of SDK documentation is not to describe a product or regurgitate the API docs.
The goal is to help a developer successfully implement that product with minimal friction and maximum confidence.
If developers can install the SDK, authenticate, make a call, handle errors, and scale usage without confusion, the documentation has succeeded.
If they hesitate, guess, or reach for support prematurely, it has not.
Good SDK documentation removes uncertainty, which can make the difference between adoption and abandonment.