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Cybersecurity · head to head

authentik vs Tenable Nessus

authentik logo

authentik

Cybersecurity

Open-source identity provider with flexible authentication flows

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: authentik smaller project than Keycloak, with a correspondingly smaller community and fewer integration guides; 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: authentik covers Configurable flows, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which authentik and Tenable Nessus actually diverge.

Attributes where authentik and Tenable Nessus differ
AttributeauthentikTenable Nessus
Pricing modelOpen-source core with a paid enterprise tiersubscription
PlatformsDocker, Kubernetes, Linux, Self-hostedWindows, 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 authentik

  • Configurable flows
  • Protocol support
  • Application proxy
  • Modern admin interface

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.

authentik

  • Self-hosted SSO across internal services without commercial identity pricingnot Tenable Nessus
  • Putting authentication in front of applications that have none, via the proxynot Tenable Nessus
  • Teams who tried Keycloak and wanted something less heavynot Tenable Nessus

Tenable Nessus

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

Where each one falls short

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

authentik

  • Smaller project than Keycloak, with a correspondingly smaller community and fewer integration guides
  • The flow model is flexible but conceptually unfamiliar, and simple setups can feel over-abstracted
  • Enterprise support and some governance features sit behind the paid tier
  • Self-hosted identity is still yours to secure, patch and keep available

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

authentik

Free
  • Open sourceFree
    • Full identity provider
    • All protocols
    • Community support

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 authentik if

  • You need configurable flows.
  • You want to start without paying.
  • You work on Docker, Kubernetes, Linux, Self-hosted.
  • You also want protocol support.
authentik 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 authentik or Tenable Nessus better?
Neither clearly leads. authentik 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, authentik or Tenable Nessus?
authentik starts at Free and Tenable Nessus at Free.
Does authentik or Tenable Nessus run on more platforms?
authentik runs on Docker, Kubernetes, Linux, Self-hosted. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use authentik for free?
Both have a free tier, so you can try either at no cost before committing.
What is authentik best used for?
authentik is most often used for self-hosted sso across internal services without commercial identity pricing, putting authentication in front of applications that have none, via the proxy, teams who tried keycloak and wanted something less heavy. Of those, self-hosted sso across internal services without commercial identity pricing and putting authentication in front of applications that have none, via the proxy are not what Tenable Nessus is typically brought in for.
What can authentik do that Tenable Nessus cannot?
authentik covers Configurable flows, Protocol support, Application proxy, Modern admin interface. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection.

Answered from the vendors’ own pages

authentik: Is authentik free?

The open-source edition is free and complete for most use. An enterprise tier adds support and additional features.

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
authentik: authentik or Keycloak?

authentik is generally reported as easier to run and administer; Keycloak is more established with a larger community and Red Hat behind it.

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
authentik: Can authentik protect apps with no login of their own?

Yes. Its application proxy places authentication in front of services that have no built-in authentication.

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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