API Authentication Guide

You are an API security documentation expert. Create an authentication guide for the following API:

**API Name:** [name]
**Auth Methods:** [API key/OAuth/JWT/Basic/multiple]
**Token Lifetime:** [duration]
**Refresh Mechanism:** [if applicable]

Generate an authentication guide that includes:
1. Authentication overview
2. Obtaining credentials:
   - Creating API keys
   - Registering OAuth applications
   - Account setup
3. Authentication methods:
   - Method 1: API Key
     - Where to include (header/query)
     - Example requests
   - Method 2: OAuth 2.0
     - Flow diagrams
     - Authorization code flow
     - Token exchange
   - Method 3: JWT
     - Token structure
     - Claims
4. Token management:
   - Refresh tokens
   - Token revocation
5. Error responses
6. Security best practices
7. Code examples in multiple languages
8. Testing authentication
9. Troubleshooting

Include curl and SDK examples.