# Postman not working to authenticate in keycloak

**URL:** <https://forum.keycloak.org/t/postman-not-working-to-authenticate-in-keycloak/28694>\
**Category:** Getting advice\
**Tags:** authentication\
**Created:** [November 12, 2024, 1:29pm UTC](https://forum.keycloak.org/t/postman-not-working-to-authenticate-in-keycloak/28694 "2024-11-12T13:29:36Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Tester123](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@Tester123](https://forum.keycloak.org/u/Tester123)\
**Post date:** [November 12, 2024, 1:29pm UTC](https://forum.keycloak.org/t/postman-not-working-to-authenticate-in-keycloak/28694/1 "2024-11-12T13:29:36Z")

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Hello,

I’ve been trying to use Postman to see if I can authenticate with Keycloak.  
I paste the URL in Postman and define username and password in form-data ( also tried x-www-form-urlencoded ) but I keep getting this error in Keycloak.

2024-11-12 13:25:51,210 WARN [org.keycloak.events] (executor-thread-172) type=“LOGIN\_ERROR”, realmId=“5d0dd960-0478-4ca6-b64a-810a3f6f4071”, realmName=“myrealm”, clientId=“null”, userId=“null”, ipAddress=“172.17.0.1”, error=“invalid\_request”, reason=“Parameter ‘client\_id’ not present or present multiple times in the HTTP request parameters”

I’ve checked and there is only one client\_id parameter.

 ![image](https://global.discourse-cdn.com/free1/uploads/keycloak/original/2X/e/e04bd380b96d089a1a5dc328e13bce07b07dd920.png)

Any ideia what might be the issue ?

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**Author:** ![Suren](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@Suren](https://forum.keycloak.org/u/Suren)\
**Post date:** [November 12, 2024, 5:24pm UTC](https://forum.keycloak.org/t/postman-not-working-to-authenticate-in-keycloak/28694/2 "2024-11-12T17:24:34Z")

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I use the token endpoint to authenticate and get the access token. Not sure if this will be useful. See the screenshot for reference. Change the master realm with your realm name.

 ![Screenshot 2024-11-12 at 9.21.25 AM](https://global.discourse-cdn.com/free1/uploads/keycloak/original/2X/c/cacc7d42b72b083678b00dc2e2f5eb41b0ce1ec9.png)

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**Author:** ![Tester123](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@Tester123](https://forum.keycloak.org/u/Tester123)\
**Post date:** [November 13, 2024, 11:18am UTC](https://forum.keycloak.org/t/postman-not-working-to-authenticate-in-keycloak/28694/3 "2024-11-13T11:18:22Z")

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Apparently everything has to be in x-www-form-urlenconded but I still wasnt able to sucessfully authenticate because the output is not the expected one.

 ![image](https://global.discourse-cdn.com/free1/uploads/keycloak/original/2X/b/b856c3bee7b02537c093c031057cb3b6f6f8e740.png)

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**Author:** ![bpedersen2](https://yyz2.discourse-cdn.com/free1/user_avatar/forum.keycloak.org/bpedersen2/32/3934_2.png) [@bpedersen2](https://forum.keycloak.org/u/bpedersen2)\
**Post date:** [November 13, 2024, 3:03pm UTC](https://forum.keycloak.org/t/postman-not-working-to-authenticate-in-keycloak/28694/4 "2024-11-13T15:03:14Z")

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2 things:

- get an understanding of how the OIDC login works: You first get a login code( which needs to be verfied with the state and challenge) which you then need to exchange for a token
- understand the difference between public and confidential clients