Free website security scanner | 8 checks, real fixes

Find Vulnerabilities.
Fix Them Yourself.

StackShield is a website security scanner built for startups and indie hackers. Scan SSL, headers, DNS, open ports, web vulnerabilities, and CVEs. Then get AI-generated fix instructions you can follow without a security team.

Free to start | No credit card requiredFull scan results in minutesAI fix & prompt packs
Domains

yourcompany.com

VERIFIEDAdded Feb 1, 2026
Next.jsCloudflareVercel
Running Port Scanner
Live45%

Last update 0s ago

Scan History

Feb 1, 2026 at 5:00 PM

manual scan

CRIT 0HIGH 0MED 2LOW 1INFO 0

// how_it_works

Run a security audit in three steps

01

Add your domain

Enter your website URL and verify ownership with a DNS TXT record or meta tag. Takes under a minute.

02

Scan for vulnerabilities

We test SSL certificates, HTTP security headers, DNS configuration, open ports, web vulnerabilities, database exposure, and known CVEs.

03

Fix issues with AI guidance

Get prioritized findings with severity ratings. Copy AI prompt packs directly into ChatGPT, Claude, or Cursor and fix issues yourself.

// scan_results

Vulnerability reports with real fix instructions

Every security scan produces a scored report with prioritized findings, severity ratings, and AI prompt packs you can act on immediately.

← yourcompany.com

Scan Results

Feb 1, 2026 at 5:00:20 PM · manual scan

23CRITICAL
COMPLETED

CRITICAL

1

HIGH

0

MEDIUM

2

LOW

3

INFO

5

Findings (11)

CRITICAL

Next.js middleware bypass (CVE-2025-29927)

Web Vulnerability Scanner

OPEN

A critical authorization bypass vulnerability was detected in your Next.js application. Attackers can bypass middleware authentication by sending a crafted x-middleware-subrequest header, gaining unauthorized access to protected routes.

Remediation

1. Upgrade Next.js immediately to a patched version:

npm install [email protected] [email protected]

2. If you cannot upgrade, add this to your middleware:

if (request.headers.get('x-middleware-subrequest')) {
return new Response('Forbidden', { status: 403 });
}

3. Redeploy your application after patching.

Reference: https://nextjs.org/blog/cve-2025-29927

MEDIUM

Legacy TLS protocol negotiated

SSL & TLS Scanner

OPEN
MEDIUM

DMARC record missing

DNS Scanner

OPEN
LOW

DKIM selectors not found

DNS Scanner

OPEN

+ 7 more findings

// pricing

Website security scanning from $0/year

Start with a free security scan. Upgrade when you need more domains, scheduled scans, and AI prompt packs on every finding.

Limited launch offer: sign up free and get a prompt pack to try AI-powered fix instructions on a finding (100 spots left).

Free

$0/year

Try it out on one domain.

Limited launch offer: 1 free prompt pack included. Try AI-powered fix instructions on a finding (100 spots left).

  • 1 domain
  • 1 scan / month
  • Summary findings
  • 1 free prompt pack (limited offer)
  • Additional prompt packs $2.99/finding
  • Scan history
Get Started
Most Popular

Builder

$149$99/year

For indie hackers shipping fast. Intro offer for first 100 paid signups.

  • 3 domains
  • 5 scans / month / domain
  • AI prompt packs on every finding
  • Full scan history
  • Overage scans ($10/2)
Start with Builder

Startup

$299$249/year

For growing teams that need coverage. Intro offer for first 100 paid signups.

  • 10 domains
  • 10 scans / month / domain
  • AI prompt packs on every finding
  • Full scan history
  • Scheduled weekly scans
  • Email notifications
  • Overage scans ($10/2)
Start with Startup

// faq

Frequently asked questions

What do you scan?

We run 8 security scanner categories: SSL/TLS certificate and protocol analysis, HTTP security headers (CSP, HSTS, X-Frame-Options, etc.), DNS configuration (SPF, DKIM, DMARC, DNSSEC, CAA), a full port scan with service detection, web vulnerability checks (mixed content, cookie flags, CORS, redirect chains), database exposure checks (open DB ports + RBAC posture), a Nuclei scanner that runs thousands of community templates to detect CVEs, misconfigurations, exposed files, default credentials, and technology fingerprinting, and a Penetration Testing scanner that performs directory discovery, injection testing, authentication weakness checks, session token analysis, and backup/config file detection.

How does domain verification work?

You can verify domain ownership in two ways: add a DNS TXT record with a unique token we provide, or place a meta tag in your homepage's HTML head. Both methods take under a minute. You must verify a domain before scanning it.

What are prompt packs?

For each finding, we generate three AI prompt packs: Fix (step-by-step instructions you can paste into ChatGPT, Claude, or Cursor), Explain (a developer-friendly explanation of the vulnerability), and Verify (a prompt to help confirm your fix works). Available on Builder and Startup plans, or $2.99 per finding on the Free plan.

Is my data secure?

All scan results are stored in an encrypted database and associated only with your account. We never share scan data. You can delete domains and their associated data at any time. We only scan domains you've verified ownership of.

Can I cancel anytime?

Yes. All plans are billed annually and you can cancel at any time through the billing portal. You'll retain access until the end of your current billing period.

Do you support custom checks?

Not yet, but it's on our roadmap. Currently we run 8 scanner categories; Including a Nuclei scanner powered by thousands of community templates and a Penetration Testing scanner. Covering the most common security issues for web applications. If you have a specific need, reach out to support.

A security audit that takes minutes, not weeks

Skip the $10k consultant. Scan your website for SSL issues, missing security headers, DNS misconfigurations, open ports, and known CVEs. Get AI prompt packs with fix instructions and resolve vulnerabilities yourself.

Scanner Coverage

Comprehensive vulnerability testing

ScannerWhat it checksPotential customer impact
SSL/TLSCertificate validity, protocol strength, cipher hygieneTrust warnings, traffic interception risk, compliance gaps
HTTP HeadersCSP, HSTS, X-Frame-Options, cookie/security headersXSS, clickjacking, session theft, account takeover risk
DNS SecuritySPF, DKIM, DMARC, DNSSEC, CAA configurationEmail spoofing, phishing abuse, brand trust damage
Port ExposureOpen ports and externally reachable servicesExpanded attack surface and unauthorized access paths
Web VulnerabilitiesRedirect issues, mixed content, CORS, insecure defaultsData leakage, browser exploitation, customer account risk
Database ExposurePublic database endpoints and weak access postureDirect data breach risk and costly incident response
Nuclei ScannerCVEs, misconfigurations, exposed files, default credentials, tech fingerprintingKnown exploit targeting, admin panel takeover, stack-specific attacks
Pen Test ScannerDirectory discovery, injection testing, auth weaknesses, session analysis, backup file detectionUnauthorized access, data exfiltration, session hijacking, source code leaks
Full vulnerability report in minutes8 security checks per scanFree to start | Plans from $99/year