APIs & SDKs for DevRel

Master API design and SDK development to improve developer experience.

Skill Contract

Parameters

parameters:
  required:
    - artifact_type: enum[api_docs, sdk, code_sample, reference]
    - language: string
  optional:
    - api_spec: object
    - version: string

Output

output:
  deliverable:
    code: string
    documentation: markdown
    tests: array[TestCase]

API Fundamentals

REST API Best Practices

GET    /users        # List users
GET    /users/:id    # Get single user
POST   /users        # Create user
PUT    /users/:id    # Update user (full)
PATCH  /users/:id    # Update user (partial)
DELETE /users/:id    # Delete user

HTTP Status Codes

Code	Meaning	Use When
200	OK	Successful GET/PUT/PATCH
201	Created	Successful POST
204	No Content	Successful DELETE
400	Bad Request	Invalid input
401	Unauthorized	Missing/invalid auth
403	Forbidden	Insufficient permissions
404	Not Found	Resource doesn't exist
429	Too Many Requests	Rate limit exceeded
500	Server Error	Something broke

SDK Design Principles

Idiomatic Code

# Python SDK - Pythonic
client = AcmeClient(api_key="...")
users = client.users.list(limit=10)

# JavaScript SDK - Modern JS
const client = new AcmeClient({ apiKey: "..." });
const users = await client.users.list({ limit: 10 });

SDK Components

SDK
├── Authentication handling
├── Request/response serialization
├── Error handling
├── Pagination helpers
├── Rate limit handling
├── Retry logic
├── Logging/debugging
└── Type definitions

API Documentation

Essential Docs

Section	Purpose
Quickstart	First API call in 5 min
Authentication	How to authenticate
Endpoints	Complete reference
Errors	Error codes and handling
Rate limits	Usage limits
Changelog	Version history

Endpoint Documentation

## Get User

`GET /users/:id`

Returns a user by their ID.

### Parameters
| Name | Type | Required | Description |
|------|------|----------|-------------|
| id | string | Yes | The user ID |

### Response
```json
{
  "id": "usr_123",
  "email": "user@example.com",
  "name": "Jane Doe"
}

Errors

• 404 - User not found
• 401 - Invalid API key

## DevRel API Responsibilities

- Advocate for developer-friendly design
- Create and maintain SDKs
- Write API documentation
- Gather feedback on DX issues
- Support developers using APIs

## Retry Logic

```yaml
retry_patterns:
  api_error_500:
    strategy: "Exponential backoff with jitter"
    max_retries: 3

  rate_limit_429:
    strategy: "Wait for retry-after header"
    fallback: "Exponential backoff"

  timeout:
    strategy: "Retry with increased timeout"
    fallback: "Return partial data"

Failure Modes & Recovery

Failure Mode	Detection	Recovery
API breaking change	Tests fail	Update SDK, notify users
SDK version mismatch	Compatibility errors	Align versions
Missing docs	Support tickets	Add documentation

Debug Checklist

□ API spec up to date?
□ SDK matches API version?
□ Error handling complete?
□ Rate limiting documented?
□ Authentication working?
□ Examples tested?

Test Template

test_apis_sdks:
  unit_tests:
    - test_api_endpoints:
        assert: "All endpoints respond"
    - test_sdk_methods:
        assert: "Match API capabilities"

  integration_tests:
    - test_end_to_end:
        assert: "Full flow works"

Observability

metrics:
  - sdk_downloads: integer
  - api_calls: integer
  - error_rate: float
  - latency_p99: duration

See assets/ for SDK templates.