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Cybersecurity · head to head

OWASP ZAP vs Silent Eight

OWASP ZAP logo

OWASP ZAP

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
Silent Eight logo

Silent Eight

Cybersecurity

AI adjudication of sanctions screening and AML alerts

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only OWASP ZAP has a free tier, so it costs nothing to try first.
  • Each has a real cost: 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.; Silent Eight automated disposition has to clear model risk governance and a regulator, and the shadow running period before auto-close is permitted can consume most of the first year of the contract.
  • They diverge on capability: OWASP ZAP covers Intercepting proxy, Silent Eight covers Alert adjudication.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which OWASP ZAP and Silent Eight actually diverge.

Attributes where OWASP ZAP and Silent Eight differ
AttributeOWASP ZAPSilent Eight
Starting priceFreeOn request
Pricing modelfreequote
Free tierYesNo
PlatformsDesktop, Cli, ApiWeb, Linux
Founded2001Unknown

Identical on both: 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 OWASP ZAP

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

Only in Silent Eight

  • Alert adjudication
  • Narrative generation
  • Name screening automation
  • Quality assurance
  • Shadow mode
  • Model transparency reporting

What people use each for

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

OWASP ZAP

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

Silent Eight

  • A bank whose level one screening team spends most of its time closing obvious false name matchesnot OWASP ZAP
  • A payments institution with alert volumes growing faster than it can recruit and train analystsnot OWASP ZAP
  • A compliance function asked by a regulator to demonstrate consistency of alert decisions across offshore teamsnot OWASP ZAP
  • An institution that has just tightened screening thresholds after an enforcement action and cannot staff the resulting alert increasenot OWASP ZAP

Where each one falls short

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

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.

Silent Eight

  • Automated disposition has to clear model risk governance and a regulator, and the shadow running period before auto-close is permitted can consume most of the first year of the contract.
  • It does not improve detection, so an institution with a poorly tuned monitoring system automates the handling of bad alerts rather than fixing why they exist.
  • Pricing is tied to alert volume, which means efficiency gains elsewhere that reduce alerts also reduce the vendor bill in a way sales teams structure minimums against.
  • The headcount saving is only realised if the institution actually reduces the analyst pool, and many banks redeploy rather than cut, leaving the business case unrealised on paper.
  • As a mid-sized private vendor serving tier one banks, concentration risk cuts both ways; the loss of one large client materially affects the company, and buyers should ask about financial stability during diligence.

Pricing, plan by plan

OWASP ZAP

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

Silent Eight

On request
  • Iris$undefined/year
    • Priced by alert volume adjudicated
    • Deploys against existing screening and monitoring systems
    • Shadow mode evaluation period

Which should you pick?

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

Choose Silent Eight if

  • You need alert adjudication.
  • You work on Web, Linux.
  • You also want narrative generation.
Silent Eight review

Questions people ask

Is OWASP ZAP or Silent Eight better?
Neither clearly leads. OWASP ZAP starts at Free and Silent Eight at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, OWASP ZAP or Silent Eight?
OWASP ZAP has a free tier; the other does not. Paid plans start at Free for OWASP ZAP and On request for Silent Eight.
Does OWASP ZAP or Silent Eight run on more platforms?
OWASP ZAP runs on Desktop, Cli, Api. Silent Eight runs on Web, Linux.
Can I use OWASP ZAP for free?
Yes. OWASP ZAP has a free tier, so you can try it without paying. Silent Eight starts at On request.
What is OWASP ZAP best used for?
OWASP ZAP is most often used for adding a baseline security scan to every application's pipeline where per-target commercial licensing would limit coverage to a handful, manual penetration testing that needs an intercepting proxy, request replay and fuzzing without a paid licence per tester, teaching developers what an attack against their own endpoint looks like, using a tool they can install themselves, pre-release regression scanning of an internal application that would never justify a commercial dast subscription. Of those, adding a baseline security scan to every application's pipeline where per-target commercial licensing would limit coverage to a handful and manual penetration testing that needs an intercepting proxy, request replay and fuzzing without a paid licence per tester are not what Silent Eight is typically brought in for.
What can OWASP ZAP do that Silent Eight cannot?
OWASP ZAP covers Intercepting proxy, Passive scanner, Active scanner, AJAX spider. Silent Eight covers Alert adjudication, Narrative generation, Name screening automation, Quality assurance.

Answered from the vendors’ own pages

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.

Silent Eight: Does Silent Eight replace our screening system?

No. It consumes alerts from your existing screening and monitoring systems and decides them. The detection layer stays where it is.

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.

Silent Eight: Will a regulator accept AI closing alerts?

It depends on your jurisdiction and your model governance evidence. Banks typically run extended shadow mode first and phase auto-closure by alert type.

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.

Silent Eight: Where is the company based?

Singapore, with offices in New York, London and Warsaw.

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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