Why Most API Documentation Is Useless (And How to Fix Yours)
Your API docs have 47 endpoints listed. Each one has the HTTP method, the path, the request body, and the response schema. It's complete, accurate, and thoroughly useless.
Why? Because when I land on your docs, I don't want to know that `POST /api/v1/strategies` accepts a JSON body. I want to know: how do I create a trading strategy with a stop loss and a take profit?
The first is a reference. The second is documentation.
The Three Types of API Docs
1. Getting Started (5 minutes to first success)
```markdown
Quick Start
1. Get your API key
curl https://api.example.com/auth/api-key
-H "Authorization: Bearer YOUR_TOKEN"
2. Create your first strategy
curl -X POST https://api.example.com/v1/strategies
-H "X-API-Key: your_key_here"
-H "Content-Type: application/json"
-d '{
"name": "My Strategy",
"symbol": "ES",
"timeframe": "15m"
}'
3. Check the result
curl https://api.example.com/v1/strategies
-H "X-API-Key: your_key_here"
```
Copy. Paste. See a result. That's all Quick Start needs to do.
2. Guides (Complete a real task)
```markdown
Guide: Setting Up Price Alerts
Price alerts notify you when a symbol crosses a price threshold.
Step 1: Create an alert
POST /v1/alerts { "symbol": "ES", "condition": "crosses_above", "price": 4500.00, "notification": "webhook" }
Step 2: Configure your webhook
POST /v1/webhooks { "url": "https://your-server.com/alert-handler", "events": ["alert.triggered"] }
Step 3: Test it
POST /v1/alerts/:id/test // This sends a test notification to your webhook ```
Notice: this guide tells a story. Step 1, 2, 3. Each step builds on the last. The developer follows a path from "I have nothing" to "I have a working alert system."
3. Reference (Every endpoint, every field)
This is what most docs are. It's valuable — but only AFTER the developer understands what the API does.
The Mistake I Made
For the Nexural API, my first docs were pure reference. 69 endpoints listed with request/response schemas. Technically complete.
The feedback: "I can see the endpoints but I have no idea where to start."
I restructured the docs:
- Quick Start (3 steps to first API call)
- Core Concepts (what is a strategy, what is a signal, how do they relate)
- Guides (create a strategy → add signals → set alerts → view results)
- Reference (the full endpoint list, auto-generated from OpenAPI)
Usage went up 5x. The API didn't change — the docs did.
Auto-Generate the Reference, Write the Guides
For the reference section, I use FastAPI's built-in OpenAPI generation:
```python @app.post("/v1/strategies", response_model=Strategy) async def create_strategy( strategy: StrategyCreate, current_user: User = Depends(get_current_user) ): """ Create a new trading strategy.
**Required fields:**
- name: Strategy display name
- symbol: Trading symbol (e.g., "ES", "NQ")
- timeframe: Candle timeframe
**Example:** See the [Getting Started guide](/docs/getting-started)
"""
...
```
FastAPI generates interactive docs at `/docs` automatically. I don't maintain the reference manually — the code IS the reference.
The guides are written by hand. They can't be auto-generated because they require understanding HOW the API should be used, not just what it can do.
The Test for Good API Docs
Give your docs to someone who's never seen your API. Set a timer. If they can't make a successful API call in 5 minutes, your docs have failed.
Not your API. Your docs.