---
title: OAuth 2.0 client authentication
description: AM can authenticate OAuth 2.0/OpenID Connect clients by using the following methods:
component: pingam
version: 7.2
page_id: pingam:oauth2-guide:oauth2-client-auth
canonical_url: https://docs.pingidentity.com/pingam/8.1/am-oauth2/oauth2-client-auth.html
llms_txt: https://docs.pingidentity.com/pingam/llms.txt
docs_for_agents: https://developer.pingidentity.com/build-with-ai/docs-for-agents.md
superseded_by: https://docs.pingidentity.com/pingam/8.1/am-oauth2/oauth2-client-auth.html
---

# OAuth 2.0 client authentication

AM can authenticate OAuth 2.0/OpenID Connect clients by using the following methods:

* [Authenticate clients with form parameters](client-auth-form.html)

* [Authenticate clients with authorization headers](client-auth-header.html)

* [Authenticate clients with JWT profiles](client-auth-jwt.html)

* [Authenticate clients with mutual TLS](client-auth-mtls.html)

Confidential clients holding a secret or a JWT bearer token assertion can authenticate with the authorization server using any of the above methods.

While confidential clients must always authenticate in one of the ways described in this section, public clients are not required to authenticate, because their information is intended to be public or they are used over insecure channels, so their secret could be easily snooped.

During authentication by HTTP POST without a `client_id` parameter, AM stores the POST data on the user-agent in an `AUTH_REQUEST_ATTRIBUTES` cookie. This cookie lets AM continue the authentication process across redirects. AM marks the cookie for deletion on the next successful OAuth 2.0 authorization.

|   |                                                                                                                                                                                                                                                                 |
| - | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|   | OAuth 2.0 and OpenID Connect clients can use the same authentication methods. However, OpenID Connect clients must specify the method they are using in their client profiles.See [OpenID Connect client authentication](../oidc1-guide/oidc-client-auth.html). |