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Validate Access Tokens
This guide explains how to verify a token's signature, manage key rotation, and how to use a refresh token to get a new access token.
Validate access tokens.
About access token validation
If you are building a modern app or API, you likely want to know if your end user is authenticated. This is important to give context or to protect APIs from unauthenticated users. You can use Okta to authenticate your end users and issue them signed access and ID tokens, which your application can then use. It is important that your application only uses the access token to grant access, and not the ID token. For more information about this, see the Access Tokens vs ID Tokens section below.
After the signed tokens are issued to the end users, they can be passed to your application for validation. There are two ways to verify a token: locally or remotely with Okta. The token is signed with a JSON Web Key (JWK) using the RS256 algorithm. To validate the signature, Okta provides your application with a public key that can be used.
- If you'd like to jump straight to the local validation steps: What to Check When Validating an Access Token
- If you'd like to see how to validate a token directly with Okta: Validating A Token Remotely With Okta
- If you want to see specifically how to accomplish this in your language of choice: Okta Libraries to Help You Verify Access Tokens
Access Tokens vs ID Tokens
As mentioned above, it is important that the resource server (your server-side application) accepts only the access token from a client. This is because access tokens are intended for authorizing access to a resource.
ID Tokens, on the other hand, are intended for authentication. They provide information about the resource owner, to allow you verify that they are who they say they are. Authentication is the concern of the clients. Because of this, when a client makes an authentication request, the ID Token that is returned contains the
client_id in the ID Token's
What to Check When Validating an Access Token
The high-level overview of validating an access token looks like this:
- Retrieve and parse your Okta JSON Web Keys (JWK), which should be checked periodically and cached by your application.
- Decode the access token, which is in JSON Web Token format
- Verify the signature used to sign the access token
- Verify the claims found inside the access token
Retrieve The JSON Web Keys
The JSON Web Keys (JWK) need to be retrieved from your Okta authorization server, though your application should have them cached. See Best practices. Specifically, your authorization server's Metadata endpoint contains the
jwks_uri, which you can use to get the JWK.
For more information about retrieving this metadata, see Retrieve Authorization Server Metadata.
Decoding and Validating the Access Token
You will have to decode the access token, which is in JWT format. This involves the following steps:
- Verify the Token Signature
- Verify the Claims
Validating A Token Remotely With Okta
Alternatively, you can also validate an access or refresh Token using the Token Introspection endpoint: Introspection Request. This endpoint takes your token as a URL query parameter and returns back a simple JSON response with a boolean
This incurs a network request which is slower to do verification, but can be used when you want to guarantee that the access token hasn't been revoked.
- A high-level overview of OpenID Connect can be found here.
- The access tokens are in JSON Web Token (JWT) (opens new window) format. They are signed using asymmetrical JSON Web Keys (JWK) (opens new window).
- More information about Okta's access tokens can be found in the OIDC & OAuth 2.0 API Reference.