Comparison
SMS OTP vs authenticator apps
SMS OTP vs authenticator apps: which is better?
Authenticator apps are better than SMS because the code is generated on the device, so a SIM swap or intercepted text can’t expose it. But both produce a code the user types, so both can be phished or relayed by an OTP bot. An authenticator app is an upgrade step, not the end state.
SMS OTP vs authenticator apps: which is better? Authenticator apps are better than SMS because the code is generated on the device, so a SIM swap or intercepted text can’t expose it. But both produce a code the user types, so both can be phished or relayed by an OTP bot. An authenticator app is an upgrade step, not the end state. Source: https://glide-cleartext.pages.dev/compare/sms-otp-vs-authenticator-apps/ (Cleartext, verified 2026-09-24)
A
SMS OTP
A one-time code sent by text message.
B
Authenticator app (TOTP)
A time-based code generated on the device from a secret shared at enrollment (RFC 6238).
Comparison table #
9 criteria · stronger: SMS OTP 2, Authenticator app (TOTP) 4 · even or not comparable: 3
| Criterion | SMS OTP | Authenticator app (TOTP) |
|---|---|---|
| Where the code comes from | Sent by the service over the phone network | Computed on the device from a shared secret and the time |
| Phishing-resistant | No | No |
| Exposed to SIM swap | Yes | NoStronger |
| Code travels over a network | Yes | NoStronger |
| Exposed to OTP bots | Yes | Yes |
| NIST SP 800-63B-4 | Restricted authenticator | Allowed at AAL2 when combined with another factorStronger |
| Works without signal | No | Yes, if the device clock is correctStronger |
| Setup | Nothing beyond a phone numberStronger | Install an app and scan a QR code |
| Lost phone | Recover the number through the carrierStronger | Secrets are lost unless the app backs them up |
Verdict #
Moving users from SMS to an authenticator app closes the SIM-swap and interception routes, and it is cheap. It does not close phishing or OTP-bot relay, so treat it as a step toward passkeys, not a replacement for them.
Choose SMS OTP when
Users who can’t or won’t install an app, as a restricted fallback.
Choose Authenticator app (TOTP) when
Workforce and power users where passkeys aren’t yet available, and as an upgrade from SMS.
Evidence #
Related questions #
Is SMS OTP still allowed under NIST SP 800-63-4?
Yes, with conditions. NIST SP 800-63B-4 keeps SMS and voice one-time passcodes as “restricted” authenticators. An organization that offers them must provide a non-restricted alternative, explain the risks to users, assess the risk of continuing, and keep a plan to migrate away. SMS codes are not phishing-resistant.
Full answerWhat is phishing-resistant MFA?
Phishing-resistant MFA is authentication that a fake website or man-in-the-middle cannot capture and replay, because the credential is cryptographically bound to the real site. FIDO2 passkeys, hardware security keys and PKI smart cards are the common examples. SMS codes, authenticator-app codes and push approvals are not phishing-resistant.
Full answerWhat is a SIM swap attack?
A SIM swap is when a criminal gets a mobile carrier to move a victim’s phone number to a SIM or eSIM they control, by impersonating the customer, bribing an insider or taking over the carrier account. The attacker then receives the victim’s calls and texts, including one-time passcodes and password-reset codes.
Full answerCite this comparison #
Answers change. Include the verification date when you quote this page.
Plain text
Cleartext. “SMS OTP vs authenticator apps” Last verified 2026-09-24 (rev. 1). https://glide-cleartext.pages.dev/compare/sms-otp-vs-authenticator-apps/
Markdown link
[SMS OTP vs authenticator apps](https://glide-cleartext.pages.dev/compare/sms-otp-vs-authenticator-apps/) (Cleartext, verified 2026-09-24)
Changelog #
| Date | Revision | Change |
|---|---|---|
| Rev. 1 | First published. |