Create 10 practical approaches to secure API authentication that help developers secure modern web applications.

Context: [API authentication, web applications, security, OAuth2, JWT, API keys, token management, access control, web security, best practices]

Goal: [Protection of APIs from unauthorized access, secure user and service authentication, prevention of security vulnerabilities, easy integration into existing systems]

For each approach explain:
1) the specific application scenario in API development
2) example implementations or workflows (e.g. OAuth2 flow, JWT usage)
3) notes on advantages, security aspects, and possible risks

The approaches should:
- cover common authentication methods for REST and GraphQL APIs
- consider aspects such as token security, expiration, and renewal
- provide recommendations for secure storage of credentials
- be suitable for developers with basic knowledge of web development