Unable to exchange Authorization Code + PKCE for user token / unable to send chat messages

[luiscyphre404-cmd]

Unable to exchange Authorization Code + PKCE for user token / unable to send chat messages

Hello Kick Dev Team,

I am developing a custom application for my own Kick channel.

What works

Using grant_type=client_credentials, I can successfully obtain an app token.

Token introspection returns:

{
  "active": true,
  "token_type": "app"
}

With this token I can successfully:

• Create event subscriptions
• Receive webhook events
• Receive chat.message.sent events

What does not work

Sending messages through:

POST /public/v1/chat

returns:

401 Unauthorized

when using the app token.

Authorization Code + PKCE

I generated a valid:

• code_verifier
• code_challenge (S256)

The authorization endpoint successfully returns an authorization code.

However, exchanging the authorization code for a user token fails.

Tests performed:

• client_id + client_secret in request body → 401
• Basic Authentication → 400

The same credentials successfully work with:

grant_type=client_credentials

Questions

1. Can POST /public/v1/chat be used with an app token obtained via client_credentials?
2. If not, what exact OAuth flow is required?
3. Is Authorization Code + PKCE currently supported for chat message publishing?
4. Which scopes are required?
5. Could you provide a working example of the token exchange request?
6. Does sending chat messages require additional approval or bot-specific credentials?

Thank you.
Luis