Documenting Features for Developers
Code alone rarely explains a feature well enough to extend it or debug it quickly. Even when it does, understanding it through code only can take unnecessary time and effort. Good documentation can help tremendously.
Write as if the reader never attended design meetings, never read the implementation tickets, or even never used the feature. The goal is to make them productive fast.
What to include:
What the feature does, its benefits and the problems it addresses
How to use it locally
application settings to enable
if any third-party service is required, how to set it up and get its credentials
data to create or seed
exact steps to follow to use the feature
expected results
This section is critical. Developers often spend more time figuring out how to use a feature than fixing the bug itself.
- How it is designed and how it works
Describe the architecture and the reasoning behind it:
key components and data flow
links to important classes, modules, and methods
trade-offs, rejected alternatives, known limitations
- Troubleshooting
Provide a practical playbook:
typical symptoms
likely causes: internal services, external APIs, configuration issues, end-users misunderstandings...
logs to check and where to find them
relevant metrics and dashboards
concrete steps to confirm and fix
- Maintenance
Document recurring tasks:
upgrades (libraries, services, dependencies)
checks to perform after upgrades
anything that requires periodic attention
- References
Link to useful resources:
external APIs
original design documents
related tickets, tests, diagrams, specs
and link to the doc from the relevant pieces of code to make it more discoverable.
Finally, treat documentation as code: keep it in the repository, version it, and review it in every PR. This "Docs-as-Code" approach prevents knowledge rot and provides AI tools with the context they need to better support development.