There are more web application security scanners than there are weeks in the year, and most comparison posts are written by whoever is selling one of them. I build one, so treat this accordingly. What I’ve tried to do below is give every tool the same four lines and an honest limitation, including my own.
All pricing verified July 2026. It moves. Check the vendor page before you commit to anything.
Free tools
Mozilla Observatory
What it checks: HTTP security headers. CSP, HSTS, X-Frame-Options and friends. What it misses: Everything else. No XSS detection, no API scanning, no dependency checks, no authentication testing. It is a header checker, not a security scanner.
Cost: Free.
Best for: A ten-second sanity check on your header configuration.
SecurityHeaders.com
What it checks: HTTP response headers, much like Observatory. What it misses: Same gaps. Headers matter, but they are one layer of defense and the easiest one to get right.
Cost: Free.
Best for: A second opinion on headers, and a cleaner grade to show someone who is not technical.
SSL Labs
What it checks: TLS configuration, certificate validity, cipher suites, protocol support. What it misses: Everything above the transport layer. Your TLS can be an A+ while your app leaks user data through a stored XSS. Cost: Free.
Best for: Verifying your certificate setup once, after you configure your domain. This is still the best tool in its category and it has no real competition.
OWASP ZAP
What it checks: Injection, XSS, CSRF, authentication issues, and more. Genuine depth. What it misses: Dependency vulnerabilities. And practically, it misses whatever you fail to configure, because it demands setup and real security knowledge to interpret output. A full active scan runs 30 to 60 minutes.
Cost: Free, Apache 2.0.
Best for: Security professionals, or anyone with the time to learn it properly. If you have that time, ZAP is very hard to beat at any price.
The honest failure mode with ZAP is not technical. Plenty of developers install it, run a scan, get several hundred findings with no prioritization, feel overwhelmed, and never open it again. A worse tool you actually run beats a better tool you abandoned.
Nuclei (ProjectDiscovery)
What it checks: Template-based scanning. Thousands of community templates for CVEs, misconfigurations, exposed panels, default credentials. What it misses: No guided remediation. Template quality varies and some are noisy. Results need security knowledge to prioritize. Cost: Free.
Best for: CLI-comfortable developers who want broad coverage and will write their own automation around it.
Nikto
What it checks: Web server misconfigurations, outdated server software, dangerous files, version-specific problems. What it misses: Modern application-layer vulnerabilities. It does not understand SPAs or modern JavaScript frameworks. It is scanning your server, not your app.
Cost: Free.
Best for: Quick server-level reconnaissance as a complement to something application-aware.
Paid tools
Snyk
What it checks: Dependency vulnerabilities, container security, IaC scanning, SAST. What it misses: Runtime vulnerabilities, security header misconfigurations, API-level issues. It reads your code and your dependencies, not your running application.
Cost: Free tier with monthly test limits. Team at $25 per developer per month, but note the constraints: it requires a minimum of 5 developers and caps at 10 licenses per org. Above that is Ignite at $1,260 per developer per year, which is a 4x jump. As of 1 January 2026, new licenses moved to a credit-consumption model.
Best for: Teams who want dependency scanning in CI. The tier cliff at 10 developers is worth planning around before you hit it.
Burp Suite Professional
What it checks: More or less everything in the DAST category, and it is the industry standard for manual web application penetration testing. What it misses: Dependency and IaC scanning, which is simply not what it is for. It also misses whatever you don’t know to look for, since its real power is manual and the tool amplifies the operator rather than replacing them. Java-based UI, heavy on modest hardware.
Cost: $475 per user per year as of the 6 January 2026 price rise, up from $449. Some sources list $499, so check portswigger.net/buy for the current figure. Burp AI is now bundled at no extra cost. Community edition is free but has no automated scanner and a throttled Intruder.
Best for: Professional penetration testers. If you test web apps for a living this is not a real decision.
Note if you’re reading older comparisons: Burp Suite Enterprise was renamed Burp Suite DAST. Pricing there is quote-based.
Detectify
What it checks: External attack surface management, OWASP Top 10, subdomain discovery, continuous monitoring. What it misses: Internal application logic, dependency vulnerabilities, code-level issues.
Cost: From $2500 annually
Best for: Companies with sprawling subdomains and external-facing services. Overkill for a single SaaS app.
Intruder
What it checks: Network-level and web application vulnerabilities. OWASP Top 10, infrastructure misconfigurations. Integrates with AWS, GCP, Azure for perimeter scanning. What it misses: Deep application logic testing. Stronger on known vulnerability patterns than on business logic flaws. Cost: From $300 monthly
Best for: Small teams wanting a managed scanner across infrastructure and application without setup overhead.
HostedScan
What it checks: Runs OpenVAS, ZAP, Nmap and SSLyze as managed cloud services. Network, web app, SSL, port scanning. What it misses: It wraps open-source tools, so it inherits their limitations. No custom remediation guidance.
Cost: From $60 monthly
Best for: Developers who want ZAP and OpenVAS without running the infrastructure.
Astra Security
What it checks: DAST covering OWASP Top 10, API security testing, business logic testing, compliance checks for GDPR, SOC 2, ISO 27001. Pentest dashboard with human verification. What it misses: Dependency scanning. Some business logic issues still need a human.
Cost: From $2000 anually
Best for: Startups that need a compliance certificate to close enterprise deals and want automated plus manual testing together.
CheckVibe
Disclosure: this is mine.
What it checks: Headers, TLS, XSS, SQL injection, CORS, CSRF, exposed API keys, plus SEO and AI visibility in the same pass. Stack-aware for Next.js, Supabase, Firebase and Vercel. Each finding comes back as a copy-paste prompt for your AI editor. MCP server for scanning from inside Claude Code or Cursor. What it misses: Dependency and SAST scanning only work if you connect a GitHub repo. On a plain URL scan you get nothing there, so Snyk or npm audit still has a job. No manual pentest layer, no compliance certification, no network or infrastructure scanning. Business logic flaws are out of scope, as they are for every automated scanner on this list.
Cost: Free to scan. Paid plans start at $24/month.
Best for: Solo developers and small teams on modern JS stacks who will not run a scanner that takes 30 minutes.
Vercel Security (built-in)
What it checks: DDoS protection, bot protection, firewall rules. What it misses: Application-level vulnerabilities entirely. It protects the infrastructure, not your code.
Cost: From $20 monthly Included with plans, WAF on Pro and above.
Best for: Vercel users, as a layer underneath application scanning, not instead of it.
What actually matters when you pick one
Speed, because it determines whether you run it twice. This is the least technical criterion and the most predictive. A scanner that takes 30 minutes gets run once, during the week you care about security, and then never again. Habit beats depth over a year.
Whether you can act on the output. “137 potential issues found” is not a security report, it is anxiety in PDF form. The question is whether a finding tells you what broke, why it matters, and what to type.
Whether it understands your stack. A scanner built for Java EE behind an F5 will not find a Supabase RLS misconfiguration. Match the tool to what you actually run.
Price proportional to revenue. Paying $275/month for a scanner at $500 MRR is not security, it is theater. The tool should cost a fraction of what the thing it protects earns.
CI or API access. Scanning on every deploy is the only version of this that survives contact with a real roadmap.
Things that matter less than vendors suggest, if you’re a solo developer or a small team: compliance certificates, unless you’re actually selling to enterprises that demand them. Network infrastructure scanning, if your platform already handles it. Manual pentest add-ons, until there’s real money or real data at stake. Agent-based scanning, if you’re serverless.
What I’d actually do
Use more than one. Nothing here covers everything, and the categories genuinely don’t overlap:
SSL Labs once, after you set up your domain
A DAST scanner on every deploy, whichever one fits your stack and budget
npm audit or Snyk in CI for dependencies
A real pentest before you handle sensitive data or close a large customer
Security is layers. Each of these is one layer, and no vendor on this list, including me, sells all of them.
FAQ
Do I need a paid scanner?
Depends what you’re building. A static marketing site with no user data: free tools are fine, genuinely. Anything with a login, a database, or payments: free tools are blind to the application layer, and that is where the incidents happen. Headers and TLS are the parts you were probably going to get right anyway.
Is OWASP ZAP good enough?
For capability, yes. It finds injection, XSS, CSRF and more, and it costs nothing. The question is whether you’ll use it. It needs installation, configuration, and enough expertise to read raw output. If you have that, ZAP is excellent and you can stop reading comparison posts. If you’re fitting security into 15 minutes between feature sprints, something with guided remediation will serve you better in practice, not because it’s better but because you’ll actually run it.
Can I use multiple scanners?
You should. SSL Labs is the gold standard for TLS and looks at nothing else. Snyk finds vulnerable dependencies and won’t find XSS in your templates. ZAP does deep application testing and ignores your lockfile. The practical setup is one DAST scanner on every deploy, dependency scanning in CI, SSL Labs once, and a human before anything that matters. One scanner that runs automatically beats five you run once a quarter.
What’s the best free scanner?
For breadth, OWASP ZAP. For headers, Mozilla Observatory. For TLS, SSL Labs. For JS dependencies, npm audit, which is already installed. For CVE templates, Nuclei. The honest answer is that no single free tool gives you comprehensive coverage with a good developer experience: free tools either cover one narrow area well or cover broadly and demand expertise. That gap is the entire business model of every paid tool on this list, mine included.
I’m Patrick, co-founder of CheckVibe, one of the scanners above. Happy to argue about any of this in the comments.
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