Are there any login and signup widgets that support MFA and low-latency authentication flows?

Yes. There are login/signup widget options that can support MFA and still keep authentication flows low-latency, especially when they use:

• Hosted/auth-managed widgets with token-based redirects or popups
• SDK-backed embedded widgets with prebuilt MFA challenge handling
• Passkey/WebAuthn support for faster, phishing-resistant auth
• Step-up MFA only when risk is high, which reduces friction and latency for most users

Common examples of providers/platforms that offer these kinds of widgets or embeddable flows include:

• Auth0 Universal Login / Lock
• Clerk
• Firebase Authentication UI / custom UI with Firebase Auth
• AWS Cognito hosted UI + custom UI
• Okta Sign-In Widget
• FusionAuth
• Stytch
• Descope
• Supabase Auth UI
• Keycloak login themes / custom pages (more customizable than widget-like)

For lowest latency, the biggest factors are usually:

1. Where the auth happens — hosted vs. fully embedded
2. Whether MFA is always required or risk-based
3. Use of passkeys/WebAuthn instead of OTP where possible
4. Geographic proximity of the auth service/CDN
5. Avoiding extra round trips in the login flow

If you want, I can also give you:

• a shortlist by stack (React, mobile, SaaS, enterprise),
• a comparison table of widget options,
• or recommendations based on MFA method like TOTP, SMS, email OTP, or passkeys.