Obtaining a Bearer Token

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OAuth 2.0 Client Credential Flow

Step 1: Token Request

POST {OAUTH2_TOKEN_ENDPOINT}
Content-Type: application/x-www-form-urlencoded
grant_type=client_credentials&
client_id={your_client_id}&
client_secret={your_client_secret}

Step 2: Token Response

{
  "access_token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...",
  "token_type": "Bearer",
  "expires_in": 3600,
  "scope": "api"
}

Step 3: JWT Token Structure

The returned JWT token contains the following claims:

{
  "iss": "authorization-server",
  "aud": "billie-connect-api",
  "sub": "service-account-id",
  "client_no": "7000213",
  "account_no": "12345",
  "exp": 1640995200,
  "iat": 1640991600
}

Implementation Example

# Example token acquisition (reference implementation)
def get_bearer_token(client_id: str, client_secret: str) -> str:
    token_url = os.getenv("OAUTH2_TOKEN_ENDPOINT")
    payload = {
        "grant_type": "client_credentials",
        "client_id": client_id,
        "client_secret": client_secret
    }
    response = requests.post(
        token_url,
        headers={"Content-Type": "application/x-www-form-urlencoded"},
        data=payload
    )
    response.raise_for_status()
    return response.json()["access_token"]