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Cybersecurity · head to head

Diligent vs Nessus

Diligent logo

Diligent

Cybersecurity

Board management and enterprise GRC platform assembled from Galvanize, Steele and Diligent Boards

From
On request
Rated
-
Full reviewWebsite
Nessus logo

Nessus

Cybersecurity

The most trusted vulnerability assessment solution

From
$4790/year
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Diligent the platform is an assembly of acquisitions, with the analytics engine from ACL, risk from Rsam, ethics and third-party diligence from Steele and the board portal from Diligent itself, so cross-module reporting and consistent user experience should be tested in a proof of concept rather than assumed.; Nessus nessus Professional is $4,790 for one year, with no free or low cost commercial tier
  • They diverge on capability: Diligent covers Diligent Boards, Nessus covers Vulnerability scanning.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Diligent and Nessus actually diverge.

Attributes where Diligent and Nessus differ
AttributeDiligentNessus
Starting priceOn request$4790/year
Pricing modelquotesubscription
PlatformsWeb, iOS, Android, WindowsDesktop, Api
FoundedUnknown2002

Identical on both: free tier (No), 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 Diligent

  • Diligent Boards
  • Entity management
  • Audit and analytics
  • Risk management
  • Third-party risk
  • Ethics and compliance
  • ESG and sustainability
  • Market intelligence

Only in Nessus

  • Vulnerability scanning
  • Configuration auditing
  • Malware detection
  • Web application scanning
  • Cloud scanning
  • Compliance checks
  • Patch auditing
  • Pre-built policies

What people use each for

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

Diligent

  • A listed company that wants board papers, entity records and the audit committee reporting pack produced from one governance systemnot Nessus
  • An internal audit function moving from sampling to full-population transaction testing using the ACL heritage analytics enginenot Nessus
  • A regulated firm consolidating a whistleblower hotline, third-party due diligence and policy attestation after an enforcement findingnot Nessus
  • A group needing sustainability disclosure data collected with the same audit trail and controls as financial reportingnot Nessus

Nessus

  • Vulnerability scanning for individual practitionersnot Diligent
  • Enterprise vulnerability managementnot Diligent
  • Web application security assessmentsnot Diligent

Where each one falls short

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

Diligent

  • The platform is an assembly of acquisitions, with the analytics engine from ACL, risk from Rsam, ethics and third-party diligence from Steele and the board portal from Diligent itself, so cross-module reporting and consistent user experience should be tested in a proof of concept rather than assumed.
  • Pricing is unpublished and consistently at the top of the market, and organisations that need only one capability, a board portal or an audit analytics tool, generally pay less and get more from a specialist.
  • Renewal leverage is weak once the board portal is embedded, because directors are the least willing user group to be migrated and that dependency is well understood by the vendor at renewal time.
  • The analytics engine expects real data skills, and audit teams without an analytics-capable member typically use a fraction of what they licensed while paying for all of it.
  • Module-by-module implementation means the promised single view of governance and risk usually arrives years after the first purchase, if the later modules are ever funded.

Nessus

  • Nessus Professional is $4,790 for one year, with no free or low cost commercial tier
  • Multi year terms are the only discount route, at $9,330.95 for two years and $13,637.54 for three
  • It is a single user scanner, so team workflows mean migrating to another Tenable product
  • Tenable One vulnerability management is priced separately, starting at $3,500 a year for 100 assets

Pricing, plan by plan

Diligent

On request
  • Diligent One Platform$undefined/year
    • Quoted by module and user count
    • Board portal seats priced separately from GRC modules
    • Annual subscription, commonly multi-year

Nessus

$4790/year
  • Nessus Professional$4790/year
    • 1 year license
    • Best for individual security professionals
  • Nessus Professional 2-Year$9330.95/2 years
    • 2 year license with discounted rate vs. annual
  • Nessus Professional 3-Year$13637.54/3 years
    • 3 year license with discounted rate vs. annual
  • Nessus Expert$6790/year
    • 1 year license
    • Enhanced capabilities vs. Professional

Which should you pick?

Choose Diligent if

  • You need diligent boards.
  • You work on Web, iOS, Android, Windows.
  • You also want entity management.
Diligent review

Choose Nessus if

  • You need vulnerability scanning.
  • You work on Desktop, Api.
  • You also want configuration auditing.
Nessus review

Questions people ask

Is Diligent or Nessus better?
Neither clearly leads. Diligent starts at On request and Nessus at $4790/year, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Diligent or Nessus?
Diligent starts at On request and Nessus at $4790/year.
Does Diligent or Nessus run on more platforms?
Diligent runs on Web, iOS, Android, Windows. Nessus runs on Desktop, Api.
What is Diligent best used for?
Diligent is most often used for a listed company that wants board papers, entity records and the audit committee reporting pack produced from one governance system, an internal audit function moving from sampling to full-population transaction testing using the acl heritage analytics engine, a regulated firm consolidating a whistleblower hotline, third-party due diligence and policy attestation after an enforcement finding, a group needing sustainability disclosure data collected with the same audit trail and controls as financial reporting. Of those, a listed company that wants board papers, entity records and the audit committee reporting pack produced from one governance system and an internal audit function moving from sampling to full-population transaction testing using the acl heritage analytics engine are not what Nessus is typically brought in for.
What can Diligent do that Nessus cannot?
Diligent covers Diligent Boards, Entity management, Audit and analytics, Risk management. Nessus covers Vulnerability scanning, Configuration auditing, Malware detection, Web application scanning.

Answered from the vendors’ own pages

Diligent: Is Diligent One the same product as Galvanize?

It contains it. Diligent bought Galvanize, the ACL and Rsam merger, for around one billion dollars in April 2021, and its audit analytics and risk modules are that heritage rebranded into Diligent One.

Nessus: What is the cheapest Nessus option?

Nessus Professional starts at $4,790 per year for a 1-year license. Multi-year commitments offer discounts, with 2-year licenses at $9,330.95 and 3-year licenses at $13,637.54.

Source
Diligent: What does Diligent cost?

Not published. It is quoted by module and user, and board portal seats are priced differently from GRC seats. Expect an annual or multi-year enterprise agreement.

Nessus: What is the difference between Nessus Professional and Expert?

Nessus Expert costs $6,790 per year for a 1-year license (compared to $4,790 for Professional) and includes enhanced capabilities. Multi-year rates are available at discounted prices.

Source
Diligent: Can you buy just the board portal?

Yes, Diligent Boards is sold on its own and is the most common entry point. The GRC modules are separate purchases.

Nessus: Does Nessus offer optional support or training?

Yes, Nessus offers add-on services: Advanced Support at $400/year provides 24x365 access to phone, email, community, and chat support. On-Demand Training costs $275/year for Fundamentals course access or $385/year for both Fundamentals and Advanced courses.

Source
Diligent: Does it replace a SOC 2 automation tool?

No. Diligent is aimed at enterprise audit, risk and governance, not at automated evidence collection for security certifications.

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