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GNAT Pro vs OWASP ZAP

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
OWASP ZAP logo

OWASP ZAP

Cybersecurity

Free, open-source web application scanner and intercepting proxy, now governed by the Software Security Project.

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Only OWASP ZAP has a free tier, so it costs nothing to try first.
  • Each has a real cost: GNAT Pro no pricing published on website; requires contacting AdaCore directly for quotes; OWASP ZAP authenticated scanning of modern single-page applications is the hard part and ZAP makes you build it by hand: session handling, token refresh and login scripts are configured per application, and a misconfigured session means the scanner logs itself out and reports a clean result for pages it never reached.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which GNAT Pro and OWASP ZAP actually diverge.

Attributes where GNAT Pro and OWASP ZAP differ
AttributeGNAT ProOWASP ZAP
Starting priceOn requestFree
Pricing modelquotefree
Free tierNoYes
PlatformsWebDesktop, Cli, Api
CategoryDeveloper ToolsCybersecurity
FoundedUnknown2001

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 GNAT Pro

Nothing recorded that OWASP ZAP does not also cover.

Only in OWASP ZAP

  • Intercepting proxy
  • Passive scanner
  • Active scanner
  • AJAX spider
  • Automation Framework
  • Headless daemon and REST API
  • Docker images
  • Add-on marketplace

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 OWASP ZAP
  • Developing automotive embedded systems with ISO-26262 compliancenot OWASP ZAP
  • Integrating Ada, C/C++, and Rust components in single codebasenot OWASP ZAP
  • Managing software supply chain vulnerabilities and SBOMsnot OWASP ZAP
  • Supporting long-lived software systems spanning decadesnot OWASP ZAP

OWASP ZAP

  • Adding a baseline security scan to every application's pipeline where per-target commercial licensing would limit coverage to a handfulnot GNAT Pro
  • Manual penetration testing that needs an intercepting proxy, request replay and fuzzing without a paid licence per testernot GNAT Pro
  • Teaching developers what an attack against their own endpoint looks like, using a tool they can install themselvesnot GNAT Pro
  • Pre-release regression scanning of an internal application that would never justify a commercial DAST subscriptionnot 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

OWASP ZAP

  • Authenticated scanning of modern single-page applications is the hard part and ZAP makes you build it by hand: session handling, token refresh and login scripts are configured per application, and a misconfigured session means the scanner logs itself out and reports a clean result for pages it never reached.
  • There is no support contract in the product, so when a scan breaks the day before a release the escalation path is a GitHub issue and a community chat, which is not an answer that satisfies a delivery manager or an auditor who wants a named responsible party.
  • Active scanning sends genuine attack traffic, so it can create records, trigger emails, exhaust rate limits or destabilise a fragile environment, and pointing it at production without prior agreement produces an incident rather than a test result.
  • Output needs triage: passive rules generate large volumes of low-severity informational findings about headers and cookie flags that bury the few results that matter, and a team without someone tuning the rule set stops reading the report within a few sprints.
  • As a dynamic scanner it can only test what it can reach, so authorisation flaws between accounts, business logic abuse and anything behind an undiscovered endpoint go unreported, and a passing ZAP scan is evidence of nothing more than the absence of the classes of bug it looks for.

Pricing, plan by plan

GNAT Pro

On request

No published plan breakdown. See the GNAT Pro review.

OWASP ZAP

Free
  • Free & Open SourceFree
    • Full functionality
    • Active & passive scanning
    • Spider

Which should you pick?

Choose GNAT Pro if

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

GNAT Pro review

Choose OWASP ZAP if

  • You need intercepting proxy.
  • You want to start without paying.
  • You work on Desktop, Cli, Api.
  • You also want passive scanner.
OWASP ZAP review

Questions people ask

Is GNAT Pro or OWASP ZAP better?
Neither clearly leads. GNAT Pro starts at On request and OWASP ZAP at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, GNAT Pro or OWASP ZAP?
OWASP ZAP has a free tier; the other does not. Paid plans start at On request for GNAT Pro and Free for OWASP ZAP.
Does GNAT Pro or OWASP ZAP run on more platforms?
GNAT Pro runs on Web. OWASP ZAP runs on Desktop, Cli, Api.
Can I use OWASP ZAP for free?
Yes. OWASP ZAP has a free tier, so you can try it without paying. GNAT Pro starts at On request.
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 OWASP ZAP is typically brought in for.
What can GNAT Pro do that OWASP ZAP cannot?
OWASP ZAP covers Intercepting proxy, Passive scanner, Active scanner, AJAX spider.

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
OWASP ZAP: Is it still called OWASP ZAP?

The project left OWASP in August 2024 and is now governed by the Software Security Project, with core development sponsored by Checkmarx. The tool is now just ZAP, though most existing documentation, courses and search results still use the OWASP name.

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
OWASP ZAP: Is it free for commercial use?

Yes. It is Apache 2.0 licensed, with no per-application, per-scan or per-user cost, and it can be used and modified commercially without a licence agreement.

OWASP ZAP: Can it replace a penetration test?

No. It automates checks for known vulnerability classes against endpoints it can reach. It does not reason about business logic, chain findings into an attack, or test authorisation between accounts, which is most of what a tester actually does.

OWASP ZAP: Does it run in CI?

Yes, through the official Docker images and the Automation Framework, which defines scan jobs in YAML so configuration lives in the repository. A baseline passive scan is the usual starting point because it is fast and non-intrusive.

OWASP ZAP: How does it compare to Burp Suite?

Burp Suite Professional is the more polished manual testing tool and has a stronger scanner and extension ecosystem, but it is licensed per tester and Burp Suite Enterprise per target. ZAP is the better fit where cost per target is the binding constraint; many teams use both.

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