Most API documentation is a generated reference: every endpoint, every parameter, every response code, technically complete and practically insufficient. It tells a developer what exists and not how to accomplish anything, which is why integrations take longer than the vendor expects and support tickets arrive asking questions the docs formally answer.
01Reference and guides are different documents
Reference documentation should be generated from the schema, because hand-written reference drifts from reality within two releases. Guides must be written by a human, because a generated document cannot explain the order in which to call things or why one approach is preferable.
The common failure is having only the first. A developer arriving at your API does not want a list of forty endpoints; they want to know how to accomplish the specific task that brought them, which usually involves three calls in a particular sequence with a decision in the middle.
| Document | Source | Answers |
|---|---|---|
| Reference | Generated from OpenAPI | What are the parameters? |
| Quickstart | Hand-written | How do I make my first call work? |
| Task guides | Hand-written | How do I accomplish X? |
| Concepts | Hand-written | How does your model work? |
| Changelog | Semi-automated | What changed and does it affect me? |
02Time-to-first-successful-call is the metric
Measure how long it takes a new developer to get one meaningful response. If that is more than about fifteen minutes, the quickstart is not doing its job, and every integration you sell will be slower and more support-intensive than it needs to be.
The obstacles are usually mundane: obtaining credentials requires a sales conversation, there is no sandbox, the first example requires values that come from another call, or the sample code does not run as written. Each is fixable and each costs you evaluation-stage prospects who quietly gave up.
03Document the errors more carefully than the successes
Developers spend most of their integration time on things not working. An error reference that lists each code, what causes it, and specifically what to do about it saves more time than any amount of prose about the happy path.
Include the errors that come from correct usage - rate limits, validation failures, conflicts from concurrent modification. Those are the ones that appear in production rather than during development, and they are exactly the ones generated documentation covers least well.
| Question | Usually documented? |
|---|---|
| How do I authenticate? | Yes |
| What does this error mean and what do I do? | Rarely |
| What are the rate limits and how do I handle them? | Sometimes |
| Is this operation idempotent? | Rarely |
| What is the ordering guarantee on webhooks? | Rarely |
| How do I test without real data? | Sometimes |
| What breaks when you change versions? | Rarely |
04Examples that run as written
Copy-paste an example from your own docs into a fresh environment. If it fails - a missing header, an undefined variable, a deprecated parameter - it will fail for every developer who tries it, and their conclusion will be that your API is fiddly rather than that your example is stale.
Test examples in CI against the real API. It is more effort than pasting a snippet, and it means your documentation cannot silently rot while your API evolves, which is the default outcome otherwise.
05Let support tickets write your roadmap
Every question your support team answers about the API is a documentation gap. Tag them, count them, and fix the top ones. That list is more accurate than any internal judgement about what is unclear, because it comes from people who tried and failed.
The strongest signal is a question asked more than three times. It means the information is either absent or present somewhere nobody looks, and both are worth fixing at the source rather than answering repeatedly.
Topics
Lena Voss
Lead Architect · SyncTrix
Writes about the engineering decisions behind production systems - architecture, delivery and the trade-offs that only show up at scale.
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