2FA is the single most effective authentication security control.
Two-factor authentication (2FA) prevents unauthorized access even when passwords are compromised. Adding TOTP (authenticator apps), SMS, or passkeys depends on the user base and security requirements. Using an established auth provider handles the complexity.
Application without two-factor authentication — either users are requesting it, enterprise customers require it, or a security audit flagged its absence
2FA options and their characteristics:
TOTP (Time-based One-Time Passwords): The Google Authenticator / Authy model. User scans a QR code to set up; enters a 6-digit code from their authenticator app at login. No SMS costs; works offline; most secure option. Standard for B2B SaaS.
SMS OTP: A 6-digit code sent via text message. Higher adoption (users don't need to set up an authenticator app). Vulnerable to SIM-swapping attacks; SMS costs per message. Use when user adoption of TOTP is a concern.
Email OTP: Code sent to the user's email. Lower security than TOTP (if email account is compromised, so is this); no setup required. Appropriate as a secondary factor for low-security applications.
Passkeys (WebAuthn): Biometric or hardware-key authentication. More phishing-resistant than TOTP. Newer standard; browser support is good; user familiarity is lower. The future of authentication.
Implementation via Clerk:
Clerk supports TOTP, SMS OTP, and passkeys out of the box. Enabling 2FA is configuration, not custom development. The enrollment flow, recovery codes, and enforcement policies are built in.
Recovery codes:
Users who lose access to their 2FA device need a recovery path. Standard approach: generate 10 single-use recovery codes at setup. User stores them securely. Using a recovery code bypasses 2FA and marks it as consumed.
Enforcement:
2FA can be optional (users opt in) or required (all users must enroll). Enterprise plans often require 2FA as a condition of access. Configurable per user role or plan tier.
Two-factor authentication supporting TOTP authenticator apps (and optionally SMS), with enrollment flow, recovery codes, and enforcement options for specific user tiers
TOTP enrollment flow
(QR code, verify, save)
2FA login challenge
(enter code after password)
Recovery codes
generation and validation
2FA management page
(enable, disable, regenerate codes)
Admin enforcement
options for requiring 2FA by role
One honest number to start.
Fixed-scope, fixed-price. The number below is the starting point — final scope is built from your brief.
Two-factor authentication supporting TOTP authenticator apps (and optionally SMS), with enrollment flow, recovery codes, and enforcement options for specific user tiers
Three steps, every time.
The same repeatable engagement on every project. No surprises, no mystery, no billable ambiguity.
Brief & discovery.
We send you questions, then get on a call. Output: a written scope with every step, feature, and integration listed.
Build & ship.
Fixed schedule, weekly reviews. No scope creep unless you change the scope — and if you do, we reprice it transparently.
Warranty & retainer.
30-day warranty on every launch. Most clients stay on a monthly retainer for ongoing features and maintenance.
Why Fixed-Price Matters Here
2FA scope is defined by the 2FA methods and whether using an auth provider or building custom. Fixed-price.
Questions, answered.
Use an auth provider (Clerk, Auth0). The edge cases in 2FA are numerous: time drift for TOTP, SMS delivery failures, recovery code management, migration if the user gets a new phone. Auth providers handle all of these.
Yes — typically enforced for admin roles and optionally available for standard users. Enterprise plan customers often require enforcement as a policy.
Tell Ryel about your project.
Describe what you’re building and what outcome you need. You’ll have a written, fixed-price scope within the week.