Lexoffice.login [SAFE]

def __init__(self, client_id, redirect_uri, scopes=None): self.client_id = client_id self.redirect_uri = redirect_uri self.scopes = scopes or ["openid", "profile", "invoice.read"] self.code_verifier = None self.state = None

– lexoffice, OAuth 2.0, PKCE, API security, cloud accounting, single-page application (SPA), authentication flow. 1. Introduction lexoffice is a leading cloud accounting software for small and medium-sized enterprises (SMEs) in Germany. Its API (documented at https://developers.lexoffice.io ) enables automated invoice creation, contact management, and financial reporting. All API endpoints require authenticated access, governed by the lexoffice.login process.

# Exchange data = "grant_type": "authorization_code", "code": auth_code, "redirect_uri": self.redirect_uri, "client_id": self.client_id, "code_verifier": self.code_verifier resp = requests.post(self.TOKEN_URL, data=data) resp.raise_for_status() tokens = resp.json() return tokens # contains access_token, refresh_token, expires_in

: Enable logging on the token exchange but redact code_verifier and refresh_token before persisting. 7. Comparison with Other Accounting APIs | Feature | lexoffice | DATEV | Xero | QuickBooks | |---------|-----------|-------|------|-------------| | OAuth2 | ✅ PKCE | ✅ PKCE | ✅ PKCE | ✅ PKCE | | Refresh token rotation | ✅ (recommended) | ❌ | ✅ | ✅ | | Sandbox environment | ✅ | ✅ | ✅ | ✅ | | Scope discovery via metadata | ✅ OIDC Discovery | ❌ | ✅ | ✅ |

def get_login_url(self): """Return the URL to redirect the user for lexoffice login.""" self.state = secrets.token_urlsafe(16) challenge = self._generate_pkce_pair() params = "response_type": "code", "client_id": self.client_id, "redirect_uri": self.redirect_uri, "scope": " ".join(self.scopes), "state": self.state, "code_challenge": challenge, "code_challenge_method": "S256" return f"self.AUTH_URL?urlencode(params)"