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Cybersecurity · head to head

Google Authenticator vs Tenable Nessus

Google Authenticator logo

Google Authenticator

Cybersecurity

Free TOTP two-factor authentication app that gained optional cloud sync in 2023

From
Free
Rated
-
Full reviewWebsite
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Google Authenticator enabling cloud sync moves the security boundary for your 2FA codes to your Google account, so a compromised Google account can expose the same codes syncing was meant to protect.; Tenable Nessus nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • They diverge on capability: Google Authenticator covers TOTP code generation, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Google Authenticator and Tenable Nessus actually diverge.

Attributes where Google Authenticator and Tenable Nessus differ
AttributeGoogle AuthenticatorTenable Nessus
Pricing modelFree, no in-app purchasessubscription
PlatformsiOS, AndroidWindows, Linux, Macos, Cloud
FoundedUnknown2002

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Cybersecurity).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Google Authenticator

  • TOTP code generation
  • QR code setup
  • Optional Google account sync
  • Offline generation
  • Manual entry

Only in Tenable Nessus

  • Network scanning
  • Vulnerability detection
  • Configuration assessment
  • Malware detection
  • Compliance checking
  • Cloud security assessment
  • Mobile scanning
  • API access

What people use each for

The jobs each tool is most often brought in to do.

Google Authenticator

  • Someone setting up two-factor authentication on a website that asks for a TOTP appnot Tenable Nessus
  • A user who wants codes to survive a lost or replaced phone via account syncnot Tenable Nessus
  • Someone who prefers a simple, free, single-purpose authenticator over a password manager's built-in onenot Tenable Nessus
  • A person migrating between phones who wants existing 2FA codes to transfer automaticallynot Tenable Nessus

Tenable Nessus

  • Vulnerability scanning of servers, network devices and web applicationsnot Google Authenticator
  • Configuration and compliance auditing against hardening benchmarksnot Google Authenticator
  • Point in time assessments by consultants and penetration testersnot Google Authenticator

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Google Authenticator

  • Enabling cloud sync moves the security boundary for your 2FA codes to your Google account, so a compromised Google account can expose the same codes syncing was meant to protect.
  • It has no built-in backup export in a portable format, so moving away from Google Authenticator to another app usually means resetting 2FA on every individual service.
  • It lacks organisational features such as folders, search or notes that some competing authenticator apps offer for people managing many accounts.
  • There is no desktop app, so codes must be read off a phone screen when logging in from a computer.
  • If sync is off and the phone is lost without a separate backup, all codes are unrecoverable and every linked account needs its 2FA reset through account recovery.

Tenable Nessus

  • Nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • Support beyond the base entitlement costs an extra $400 per year for Advanced Support with 24x365 phone and chat access
  • The on demand training course is a separate $275 purchase for a single person for one year
  • Multi year discounts require paying for two or three years up front

Pricing, plan by plan

Google Authenticator

Free
  • FreeFree
    • Unlimited accounts and codes
    • Optional Google account cloud sync
    • No ads

Tenable Nessus

Free
  • Nessus EssentialsFree
    • Up to 16 ips
    • Network scanning
    • Vulnerability assessment
  • Nessus Professional$2600/year
    • Unlimited targets
    • Enterprise features
    • Advanced analytics
  • Nessus Expert$5200/year
    • All Professional features
    • Cloud integration
    • Advanced reporting

Which should you pick?

Choose Google Authenticator if

  • You need totp code generation.
  • You want to start without paying.
  • You work on iOS, Android.
  • You also want qr code setup.
Google Authenticator review

Choose Tenable Nessus if

  • You need network scanning.
  • You want to start without paying.
  • You work on Windows, Linux, Macos, Cloud.
  • You also want vulnerability detection.
Tenable Nessus review

Questions people ask

Is Google Authenticator or Tenable Nessus better?
Neither clearly leads. Google Authenticator starts at Free and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Google Authenticator or Tenable Nessus?
Google Authenticator starts at Free and Tenable Nessus at Free.
Does Google Authenticator or Tenable Nessus run on more platforms?
Google Authenticator runs on iOS, Android. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Google Authenticator for free?
Both have a free tier, so you can try either at no cost before committing.
What is Google Authenticator best used for?
Google Authenticator is most often used for someone setting up two-factor authentication on a website that asks for a totp app, a user who wants codes to survive a lost or replaced phone via account sync, someone who prefers a simple, free, single-purpose authenticator over a password manager's built-in one, a person migrating between phones who wants existing 2fa codes to transfer automatically. Of those, someone setting up two-factor authentication on a website that asks for a totp app and a user who wants codes to survive a lost or replaced phone via account sync are not what Tenable Nessus is typically brought in for.
What can Google Authenticator do that Tenable Nessus cannot?
Google Authenticator covers TOTP code generation, QR code setup, Optional Google account sync, Offline generation. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection.

Answered from the vendors’ own pages

Google Authenticator: Does Google Authenticator cost anything?

No, it is free with no subscription or in-app purchases.

Tenable Nessus: What are the three Nessus offerings?

Nessus Essentials is a free introductory offering for educators, students, and career starters, limited to 16 IPs for scanning. Nessus Professional is designed for consultants and SMBs, providing unlimited IT scans across any location. Nessus Expert is the premium offering extending Professional with web application scanning, infrastructure-as-code scanning, and external attack surface assessment up to 5 domains.

Source
Google Authenticator: Is cloud sync safe?

Google documents it as protected by your Google account security. Whether that is an acceptable trade-off versus device-only storage is debated; you can turn sync off if you prefer local-only codes.

Tenable Nessus: What OS platforms does Nessus support?

Nessus runs on Debian/Kali Linux, Fedora, FreeBSD, Mac OS X, Red Hat/CentOS, SUSE Linux, Ubuntu, and various Windows versions including Server 2008, 2012, and Windows 7-10.

Source
Google Authenticator: Can I export my codes to another app?

There is no official bulk export; moving to a different authenticator typically requires re-adding each account from its setup page.

Tenable Nessus: Can I use Nessus to scan third-party networks as a consultant?

Yes, Tenable permits you to use Nessus to scan third-party networks. Nessus Professional is ideal for consultants.

Source
Tenable Nessus: Can Nessus perform PCI external scanning?

Yes, you can use Nessus Professional to perform external network scans as required by the PCI DSS 11.2.2 requirement.

Source
Tenable Nessus: What additional features does Nessus Expert provide?

Web application scanning, which is dynamic application security testing (DAST) providing comprehensive visibility and insight into web application security issues; scanning code repositories for vulnerabilities; and assessing external attack surface with subdomain discovery.

Source
Tenable Nessus: What support options exist for Nessus Professional?

Standard Support includes software upgrades, patches, plugin access, and 24x7 support via chat and community portal. Advanced Support adds 24x7 phone access and committed SLAs: P1 less than 2 hours, P2 less than 4 hours, P3 less than 12 hours, P4 less than 24 hours.

Source
Tenable Nessus: How frequently are Nessus plugins updated?

Nessus plugins are updated daily, based on when vendors and security research sites publish new vulnerabilities.

Source
Tenable Nessus: How does licensing work in virtual machine environments?

Whether you are using Nessus in a physical or a virtual environment, the IP addresses or hosts that you are scanning from must be licensed.

Source
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