What is Bearer token authentication?

Bearer token is a standard authentication method in HTTP, used in OAuth 2.0 and other protocols. The client sends the token in the Authorization header with the Bearer prefix.

Authorization: Bearer <token>

The server verifies the token's validity and, if it is valid, grants access to the protected resource. The token usually is a string, such as a JWT (JSON Web Token), containing information about the user and their permissions.

Advantages:

• Simple to implement.
• Secure when used with SSL/TLS.
• Low server load due to statelessness.

Disadvantages:

• Risk of token theft (data compromise).
• Need for a mechanism to revoke tokens in case of theft or user logout.

Used in RESTful APIs, Single Page Applications, mobile applications.