Multi-factor authentication confirms who you are by requiring more than one independent proof of identity. Rather than trusting a single password, it asks for at least two factors from different categories: something you know, something you have, and something you are. Get one wrong and the door stays shut.
The reason this works comes down to independence. A password can leak in a breach, get phished, or be reused from another site, and you might never notice. But for an attacker to also hold your phone or your fingerprint at the same moment is a much taller order. It is the difference between a lock that needs one key and a lock that needs two kept in separate pockets. Strong authentication like this is now a baseline expectation, not a luxury.
MFA pairs especially well with single sign-on: users sign in once with multiple factors, and that one strong login then covers every connected app. The factors vary in strength, so for sensitive accounts an authenticator app or hardware key beats a text-message code.
That last point is worth dwelling on. SMS codes can be intercepted through SIM swapping, where an attacker convinces a carrier to move your number to their phone. Push-approval apps face a different trap: people tap “approve” out of habit when prompts flood in, a trick known as MFA fatigue. A passkey or hardware key sidesteps both, since there is nothing to type and nothing to intercept. The same idea sits behind access control, where the strength of the proof should match how sensitive the thing being protected is.
One practical caveat: plan for the day someone loses their phone. Without a recovery path, like backup codes printed once or a second registered device, a strong MFA setup can lock out the very people it was meant to protect.
At TopDevs we make MFA the default on admin accounts and client systems, since it removes the most common path attackers take, a stolen or reused password.
