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Legal · head to head

Relativity vs Tenable Nessus

Relativity logo

Relativity

Legal

Ediscovery and legal data platform for large matters

From
On request
Rated
-
Full reviewWebsite
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Tenable Nessus has a free tier, so it costs nothing to try first.
  • Each has a real cost: Relativity quote-only and expensive, typically billed on data volume, so costs escalate with matter size; 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: Relativity covers Large-scale processing, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

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

Attributes where Relativity and Tenable Nessus differ
AttributeRelativityTenable Nessus
Starting priceOn requestFree
Pricing modelquotesubscription
Free tierNoYes
PlatformsWeb, Cloud, Self-hostedWindows, Linux, Macos, Cloud
CategoryLegalCybersecurity
FoundedUnknown2002

Identical on both: user rating (Not yet rated).

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 Relativity

  • Large-scale processing
  • Review workflow
  • Analytics and active learning
  • Application ecosystem

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.

Relativity

  • Large litigation with very high document volumesnot Tenable Nessus
  • Corporate investigations requiring defensible, auditable reviewnot Tenable Nessus
  • Firms whose review process is already built around the platformnot Tenable Nessus

Tenable Nessus

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

Where each one falls short

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

Relativity

  • Quote-only and expensive, typically billed on data volume, so costs escalate with matter size
  • Complex enough that certified specialists are a job title, which is a real staffing cost
  • Considerable overkill for small matters, where lighter self-service tools are far cheaper

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

Relativity

On request

No published plan breakdown. See the Relativity review.

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 Relativity if

  • You need large-scale processing.
  • You work on Web, Cloud, Self-hosted.
  • You also want review workflow.
Relativity 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 Relativity or Tenable Nessus better?
Neither clearly leads. Relativity starts at On request and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Relativity or Tenable Nessus?
Tenable Nessus has a free tier; the other does not. Paid plans start at On request for Relativity and Free for Tenable Nessus.
Does Relativity or Tenable Nessus run on more platforms?
Relativity runs on Web, Cloud, Self-hosted. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Tenable Nessus for free?
Yes. Tenable Nessus has a free tier, so you can try it without paying. Relativity starts at On request.
What is Relativity best used for?
Relativity is most often used for large litigation with very high document volumes, corporate investigations requiring defensible, auditable review, firms whose review process is already built around the platform. Of those, large litigation with very high document volumes and corporate investigations requiring defensible, auditable review are not what Tenable Nessus is typically brought in for.
What can Relativity do that Tenable Nessus cannot?
Relativity covers Large-scale processing, Review workflow, Analytics and active learning, Application ecosystem. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection.

Answered from the vendors’ own pages

Relativity: What does Relativity cost?

It does not publish rates. Ediscovery is generally billed on data volume and users, quoted per matter or organisation.

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
Relativity: Is Relativity only for law firms?

No. Corporate legal departments and government agencies use it for investigations as well as litigation.

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
Relativity: Do I need trained staff?

In practice yes. Relativity certification is a recognised specialism, and that staffing cost is part of the total.

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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