Refresh Token Flow
When your access token expires, you can use the refresh token to obtain a new access token without requiring the user to re-authenticate. The refresh token is provided in the initial token exchange response.
Endpoint: POST /oauth/token
{
"grantType": "refresh_token",
"refreshToken": "string",
"clientId": "string",
"signature": "string" // SHA-256 hash of grantType + refreshToken + clientId + clientSecret
}