Duo Mobile vs OpenOTP Authentication Server

Duo Mobile provides two-factor and multi-factor authentication for company and personal data on iOS and Android phones and tablets. Users can approve or deny sign-ins with Duo Push, or enter time-based passcodes generated by the app. It also supports third-party TOTP accounts, biometrics, and passcodes. Duo Restore backs up and restores Duo-protected accounts when a user changes devices, and Security Checkup provides a mobile-device security score through app notifications. For organizations, Duo connects with legacy infrastructure, custom apps, VPNs, SaaS tools, and offline devices. Integration methods include RADIUS, SAML/OIDC, Duo Authentication Proxy, and direct API connections. Adaptive policies can consider user role, location, application, network, and device health. Duo says it keeps private keys on users’ devices in a tamper-proof secure element and does not store passwords. The free plan covers 10 users; paid plans start at $3.00 per month, and a 30-day trial is listed. End users needing enrollment or troubleshooting help are directed to their organization’s Duo administrator.

OpenOTP Authentication Server is an authentication and identity management solution for multi-factor access, offered for cloud or on-premise deployment. It supports mobile push, smart-card certificates, secure magic links, YubiKey, FIDO2 passkeys and software tokens, alongside factors such as SMS, email, hardware tokens and OATH. Federated access options include SAML, OIDC and OAuth. Directory and identity integrations include Active Directory, LDAP, Entra ID, Okta, Google, Ping Identity and One Identity. The server also provides EAP network access control, mobile electronic signatures and mobile badging. Windows and macOS login plugins are listed, as are PAM plugins for Linux and macOS. OpenOTP is a WebADM sub-package and cannot be installed standalone. Pricing is on request, with a 30-day trial: the cloud trial supports up to 250 OpenOTP users and 50 SpanKey hosts; the on-premise trial supports up to 10 users and includes two active-active HA servers. The Freeware plan costs nothing and includes documentation and forum support only. Enterprise Edition is listed at €1.90 a year, and Enterprise Edition + SLA at €2.28 a year; both prices are shown per user/month based on 250 users and billed annually.