OAuth 2.0 access tokens are an essential part of the OAuth 2.0 protocol, allowing third-party applications to access protected resources on behalf of a user. This guide provides an overview of access tokens, their usage, and how to obtain them.
What is an Access Token?
An access token is a credential that represents a set of permissions granted to a client application by an authorization server. It is used to access protected resources on behalf of the resource owner (user).
How to Obtain an Access Token
To obtain an access token, the client application must first authenticate with the authorization server. This can be done using various flows, such as the Authorization Code Flow or the Client Credentials Flow.
Authorization Code Flow
- The client application redirects the user to the authorization server's authorization endpoint.
- The user authenticates with the authorization server and consents to the requested permissions.
- The authorization server redirects the user back to the client application with an authorization code.
- The client application exchanges the authorization code for an access token.
Client Credentials Flow
- The client application authenticates with the authorization server using its client credentials.
- The authorization server validates the client credentials and responds with an access token.
Usage of Access Tokens
Once an access token is obtained, it can be used to access protected resources on behalf of the user. The access token should be included in the Authorization header of the HTTP request as a Bearer token.
GET /protected/resource HTTP/1.1
Host: example.com
Authorization: Bearer <access_token>
Security Considerations
Access tokens are sensitive information and should be protected. They should be stored securely and not exposed to unauthorized parties. Additionally, access tokens should have a limited lifetime to reduce the risk of misuse.
More Information
For more detailed information about OAuth 2.0 access tokens, please refer to the official OAuth 2.0 specification.