Alternatives to Duende IdentityServer

FusionAuth

It suits teams managing end-user identity at scale that need authentication and authorization across applications.

Google Cloud Identity

Cloud Identity suits organizations that need centralized user and group management, app SSO, device controls, and automated provisioning.

Ory

Ory suits teams building identity and access management into customer, partner, machine, or AI-agent products.

Auth0 Guardian

It suits organizations needing mobile push approvals or temporary OTPs for MFA, and teams building custom applications with Guardian SDKs.

authentik

The open-source edition is described for homelab users and simple use cases.

Descope

Descope suits developers building customer or business applications that need authentication, user management and authorization.

Curity Identity Server

Community is described as suitable for individuals or start-ups; Standard is for growing teams, and Enterprise for organizations with multiple teams or large deployments.

Frontegg

Frontegg suits developers and product teams adding customer identity to applications, particularly B2B products with tenant-level policies.

It suits teams building consumer apps, SaaS products or enterprise applications needing authentication and authorization.

It is designed for SaaS founders, product teams, and engineers wanting authentication, billing, and feature flags in one cloud platform.

Okta Customer Identity Cloud

Auth0 suits organizations that need authentication and access controls for applications, including single sign-on, passwordless options, or machine-to-machine access.

Stytch suits developers building applications that need authentication, organization access controls, fraud protection or identity services for integrations.