Add passkeys and adaptive MFA to your C# app.

Drop Authsignal into your C# backend with our server SDK. Ship phishing-resistant passkeys, adaptive MFA, and a no-code rules engine on top of your existing auth, with no rip-and-replace. Live in weeks, not months.

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Delivering world-class results for:

Fastest way to integrate MFA and passkeys with C#

Ship passkeys and adaptive MFA from your C# backend without re-architecting your auth

Pre-built UI, UI components, or fully custom. Choose the integration path that fits your stack

Phishing-resistant authentication live in weeks, backed by a visual no-code rules engine

From daunting rebuild to shipped in weeks

Drop-in

Security

Adaptive security without the friction

The no-code rules engine applies the right authentication at the right moment, challenging high-risk actions with step-up MFA while keeping low-risk logins fast. Product, fraud, and compliance teams set the rules. Engineering ships once.

Journey

Authentication across the entire customer journey

3 ways to integrate with C#

Get started for free with up to 2000 monthly active users.

“Implementing FIDO authentication through Authsignal has been a game-changer for our members’ digital experience. It’s secure, seamless and sets a new standard for trust in online banking.”

Herb Wulff · Treasury and Agency

Treasury and Agency Banking Manager

Partnering with Authsignal is simple and powerful

Start with a guided evaluation

Talk to our team to scope your integration and see a live demo tailored to your stack.

Quick & easy integration

Dedicated solutions engineering

Access real-time support via our private Slack channel for tailored advice from our engineering team.

Flexible pricing

Start for free. Drop-in authentication for production-grade security and compliance, without replacing your existing identity stack.

FAQ

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Why choose Authsignal?

Deploy passkeys and MFA in weeks instead of months. Flexible integration options including pre-built UI, UI components, or headless SDKs. A visual no-code rules engine for adaptive authentication policies. Real-time developer support, comprehensive documentation, and step-by-step integration guides. SOC 2 Type 2, ISO 27001, and FIDO Alliance certified.

What does it cost to integrate with Authsignal?

You can start integrating on our free tier immediately — up to 1,000 monthly active users at no cost. For production deployments, plans start at $1,099/month. Enterprise pricing is available for larger deployments. See our pricing page for details.

Which MFA methods does Authsignal support?

Passkeys (FIDO2/WebAuthn), biometrics, SMS OTP, email OTP, WhatsApp OTP, push notifications, authenticator apps (TOTP), and magic links. All methods are available from a single integration and managed via the no-code rules engine.

What programming languages and SDKs are supported?

Server SDKs for Node.js, Python, Ruby, Java, C#, PHP, and Go. Client SDKs for Web (JavaScript/TypeScript), React Native, iOS (Swift), and Android (Kotlin). Plus a REST API for any language.

Resources and guides

View the docs

Drop-in MFA, passkeys & step-up auth — no migration required.

Add passkeys and adaptive MFA in C# with Authsignal.

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