OATH (Open Authentication) vs ZITADEL: Side-by-Side Comparison (2026)

OATH (Open Authentication): Vendor-neutral org publishing open standards for OTP & strong auth. built by OATH (Open Authentication). Core capabilities include Open, royalty-free OTP specifications (HOTP, TOTP, OCRA), HOTP (RFC 4226): counter-based HMAC one-time password standard, TOTP (RFC 6238): time-based one-time password standard..

ZITADEL: Open-source, multi-tenant identity platform for authn, authz, and SSO. built by ZITADEL. Core capabilities include Hosted login page with customizable branding, Multi-factor authentication (MFA) enforcement, Passwordless authentication via Passkeys..

Both serve the Multi-Factor Authentication and Single Sign-On market but differ in approach, feature depth, and target audience.

OATH (Open Authentication) differentiates with Open, royalty-free OTP specifications (HOTP, TOTP, OCRA), HOTP (RFC 4226): counter-based HMAC one-time password standard, TOTP (RFC 6238): time-based one-time password standard. ZITADEL differentiates with Hosted login page with customizable branding, Multi-factor authentication (MFA) enforcement, Passwordless authentication via Passkeys.

OATH (Open Authentication) is developed by OATH (Open Authentication). ZITADEL is developed by ZITADEL. Vendor maturity, funding stage, and team size can be important factors when evaluating long-term viability and support quality.

OATH (Open Authentication) and ZITADEL serve similar Multi-Factor Authentication and Single Sign-On use cases: both are Multi-Factor Authentication and Single Sign-On tools, both cover Authentication, MFA, Open Source. Key differences: OATH (Open Authentication) is Free while ZITADEL is Commercial. Review the feature comparison above to determine which fits your requirements.