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Cybersecurity · head to head

OWASP ZAP vs Unleash

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
-
Unleash logo

Unleash

Software Development

Open-source feature flag and experimentation service

From
Free
Rated
-

The short version

  • 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.; Unleash the Pay-As-You-Go plan is priced per seat, which can get costly for larger teams.
  • They diverge on capability: OWASP ZAP covers Intercepting proxy, Unleash covers Feature flags.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which OWASP ZAP and Unleash actually diverge.

Attributes where OWASP ZAP and Unleash differ
AttributeOWASP ZAPUnleash
Pricing modelfreefreemium
PlatformsDesktop, Cli, Apiweb, api, linux
CategoryCybersecuritySoftware Development
Founded2001Unknown

Identical on both: starting price (Free), free tier (Yes), 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 OWASP ZAP

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

Only in Unleash

  • Feature flags
  • A/B/n testing
  • Custom targeting
  • SDKs
  • SSO
  • Audit logs

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 Unleash
  • Manual penetration testing that needs an intercepting proxy, request replay and fuzzing without a paid licence per testernot Unleash
  • Teaching developers what an attack against their own endpoint looks like, using a tool they can install themselvesnot Unleash
  • Pre-release regression scanning of an internal application that would never justify a commercial DAST subscriptionnot Unleash

Unleash

  • Gradual and progressive feature rolloutsnot OWASP ZAP
  • Running A/B/n experiments tied to flagsnot OWASP ZAP
  • Self-hosting feature management for compliance needsnot OWASP ZAP
  • Enterprise SSO-controlled feature flag governancenot 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.

Unleash

  • The Pay-As-You-Go plan is priced per seat, which can get costly for larger teams.
  • Self-hosted Enterprise requires a minimum of 5 seats and an annual contract.
  • Additional API traffic beyond the included quota is billed per million requests.
  • Advanced SLAs and dedicated customer success are reserved for the custom Enterprise tier.

Pricing, plan by plan

OWASP ZAP

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

Unleash

Free
  • Pay-As-You-Go$75/month
    • Cloud-hosted
    • 53M API requests/month included
    • Unlimited feature flags, projects and environments
  • Custom Enterprise$undefined/mo
    • Cloud, self-hosted or hybrid
    • Premium support options
    • 99.99% uptime SLA

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.

Choose Unleash if

  • You need feature flags.
  • You want to start without paying.
  • You work on web, api, linux.
  • You also want a/b/n testing.

Questions people ask

Is OWASP ZAP or Unleash better?
Neither clearly leads. OWASP ZAP starts at Free and Unleash at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, OWASP ZAP or Unleash?
OWASP ZAP starts at Free and Unleash at Free.
Does OWASP ZAP or Unleash run on more platforms?
OWASP ZAP runs on Desktop, Cli, Api. Unleash runs on web, api, linux.
Can I use OWASP ZAP for free?
Both have a free tier, so you can try either at no cost before committing.
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 Unleash is typically brought in for.
What can OWASP ZAP do that Unleash cannot?
OWASP ZAP covers Intercepting proxy, Passive scanner, Active scanner, AJAX spider. Unleash covers Feature flags, A/B/n testing, Custom targeting, SDKs.

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.

Unleash: What does Unleash cost?

Unleash offers a Pay-As-You-Go cloud plan at $75/seat/month with a 14-day free trial, plus a custom-priced Enterprise plan for self-hosted or hybrid deployments.

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.

Unleash: How is usage metered?

The Pay-As-You-Go plan includes 53M API requests per month, with additional traffic billed at $5 per million requests thereafter.

Source
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.

Unleash: What does Unleash integrate with, and is there an API?

Unleash provides an API and 25+ official SDKs across languages, along with SSO integrations via SAML 2.0 and OpenID Connect.

Source
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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