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GNAT Pro vs Nessus

GNAT Pro logo

GNAT Pro

Developer Tools

Software development environments and toolchains for Ada, C/C++ and Rust

From
On request
Free plan
No
Full reviewWebsite
Nessus logo

Nessus

Cybersecurity

The most trusted vulnerability assessment solution

From
$4790/year
Free plan
No
Full reviewWebsite

The short version

  • Each has a real cost: GNAT Pro no pricing published on website; requires contacting AdaCore directly for quotes; Nessus nessus Professional is $4,790 for one year, with no free or low cost commercial tier
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which GNAT Pro and Nessus actually diverge.

Attributes where GNAT Pro and Nessus differ
AttributeGNAT ProNessus
Starting priceOn request$4790/year
Pricing modelquotesubscription
PlatformsWebDesktop, Api
CategoryDeveloper ToolsCybersecurity
FoundedUnknown2002

Identical on both: free tier (No), 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 GNAT Pro

Nothing recorded that Nessus does not also cover.

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.

GNAT Pro

  • Building certified avionics software meeting DO-178B/C standardsnot Nessus
  • Developing automotive embedded systems with ISO-26262 compliancenot Nessus
  • Integrating Ada, C/C++, and Rust components in single codebasenot Nessus
  • Managing software supply chain vulnerabilities and SBOMsnot Nessus
  • Supporting long-lived software systems spanning decadesnot Nessus

Nessus

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

Where each one falls short

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

GNAT Pro

  • No pricing published on website; requires contacting AdaCore directly for quotes
  • Vendor indicates per-user, per-year subscription model but does not disclose specific costs

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

GNAT Pro

On request

No published plan breakdown. See the GNAT Pro review.

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 GNAT Pro if

Nothing in the data separates GNAT Pro from Nessus on the points above - pick on price and on how each one feels to use.

GNAT Pro review

Choose Nessus if

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

Questions people ask

Is GNAT Pro or Nessus better?
Neither clearly leads. GNAT Pro 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, GNAT Pro or Nessus?
GNAT Pro starts at On request and Nessus at $4790/year.
Does GNAT Pro or Nessus run on more platforms?
GNAT Pro runs on Web. Nessus runs on Desktop, Api.
What is GNAT Pro best used for?
GNAT Pro is most often used for building certified avionics software meeting do-178b/c standards, developing automotive embedded systems with iso-26262 compliance, integrating ada, c/c++, and rust components in single codebase, managing software supply chain vulnerabilities and sboms. Of those, building certified avionics software meeting do-178b/c standards and developing automotive embedded systems with iso-26262 compliance are not what Nessus is typically brought in for.
What can GNAT Pro do that Nessus cannot?
Nessus covers Vulnerability scanning, Configuration auditing, Malware detection, Web application scanning.

Answered from the vendors’ own pages

GNAT Pro: How much does GNAT Pro cost?

GNAT Pro pricing is not published on the website. Customers must request a pricing quote by contacting AdaCore directly or speaking with a GNAT Pro expert.

Source
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
GNAT Pro: What is GNAT Pro licensing model?

GNAT Pro is sold on a per-user, per-year basis with no license locks. Customers can request pricing for their specific needs.

Source
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
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
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