Legacy Logins to Modern Applications
Centralize authentication and token security across fragmented legacy estates. Deliver secure SSO and velocity without application rewrites.
Talk to an ExpertChallenge
Modernization Without Rewrites Feels Impossible
Your business relies on a large estate of legacy .NET apps with hardcoded, outdated, or inconsistent authentication logic. Rewrites aren't feasible. Your team is trapped in manual patches, duplicated policies, and mounting security debt. Users face repeated logins, auditors flag outdated flows, and promised SaaS "modernization" falls short lacking .NET-native integration, control, and phased rollout flexibility.
Impact
And Doing Nothing
Only Makes It Worse
Without a central identity layer, teams remain buried in legacy authentication stacks. Policy changes take weeks, MFA and claims enforcement are inconsistent, and every audit exposes new gaps. Developers are blocked by vendor rigidity, unable to adopt modern standards or streamline security. Rising friction and operational debt continue to grow over time.
Duende IdentityServer customers:
Trusted by over 2500 enterprises modernizing with secure, standards-based identity.
Solution
The .NET-Native Path to Modern Applications and Identity
Deliver SSO, central policy, and modern sessions across legacy apps - without the cost and risk of a full application rewrite. Duende introduces a modern identity core that modernizes authentication without touching business code. Apps keep running, but login, sessions, and tokens are externalized and standardized.
Secure SSO for legacy apps:
Protocol adapters deliver SSO even when legacy apps can't speak OIDC/OAuth.
Phased Decomposition:
Gradually extract login, session, and token management from monoliths - minimal disruption and downtime.
Modern Session & Token Management:
Adopt modern, secure standards for session and token issuance across your entire estate.
Central Policy & Extensibility:
Uncompromised control over the UI, business logic, and policy plane. Define MFA rules, claims, and session lifetimes in one place, even for legacy users.
Benefit
Faster, Safer Modernization
with Predictable Control
Eliminate compromise between control and commercial readiness. Centralize authentication to eliminate fragmentation, strengthen security, and modernize legacy apps - without the cost and risk of rewrites.
One Policy Everywhere
Enforce identity rules across all apps
Modern Standards
Adopt OIDC, OAuth2, and PKCE easily
Reduced Risk & Cost
Phase modernization, avoid costly rewrites
Developer Alignment
Native .NET identity built by experts
Predictable at Scale
Scale confidently with transparent pricing