A passkey (Face ID, Touch ID, Windows Hello, or a security key) signs you in with one touch and skips the one-time code. Phishing-resistant; recommended.
Sign-in codes (2FA)
Password
API keys
Use a key for automation: Authorization: Bearer sk_… on POST /api/check and POST /api/history. Calls are billed from this balance at the same token rates. Docs & examples.