Is there a free website security scanner API?

Yes. Vuln0x provides a REST API that lets you trigger scans programmatically and retrieve results in JSON. Free accounts receive 50 credits on signup — enough for 50 full scans — with no credit card required. API keys are available from your account dashboard, and pre-built GitHub Actions workflows make it straightforward to add a security scan gate to every pull request.

What is the difference between a security scanner and a vulnerability scanner?

The terms are often used interchangeably, but there is a practical distinction. A website security scanner focuses on configuration and hygiene signals — HTTP headers, TLS settings, blocklist status, exposed sensitive files, and misconfigurations that raise overall risk. A vulnerability scanner goes deeper into application logic, probing for exploitable flaws such as XSS, SQL injection, SSRF, and known CVEs. Vuln0x's free passive check is security-scanner-grade; the full 40+ engine scan covers both security configuration and application vulnerabilities.

What does Vuln0x's website security scanner check?

The passive surface check covers HTTP security headers (CSP, HSTS, X-Frame-Options, Referrer-Policy, Permissions-Policy), TLS certificate validity and cipher strength, cookie security attributes (HttpOnly, Secure, SameSite), blocklist and malware signals, and obviously exposed files such as .env or backup archives. The full scan adds 40+ deeper checks including XSS, SQL injection, CORS misconfigurations, and framework-specific CVEs.

How do I use Vuln0x as the best website security scanner for CI/CD?

Sign up for a free account to get your API key, then add the Vuln0x GitHub Action to your workflow YAML. The action submits a scan on every pull request, waits for results, and fails the check if the security score drops below your configured threshold. Results are exported as SARIF and posted directly to the GitHub Security tab. Full documentation is available at /features/api-cicd.

Is the website security scan safe to run on a live production site?

Yes. The passive check sends the same HTTP requests a browser or search-engine bot would send — it never modifies data or exploits vulnerabilities. The full scan's active probes are also designed to be non-destructive, but if you prefer, you can point Vuln0x at a staging environment first and compare results before running against production.

Free Website Security Scanner

Paste any URL and get an instant A+ to F security grade. Vuln0x checks headers, TLS, malware blocklist signals, misconfigurations, and exposed files — no account needed for the quick check, no install ever.

Scan your website free

What is a website security scanner?

A website security scanner is an automated tool that inspects your web application for configuration weaknesses, exposure risks, and known threat signals before an attacker exploits them. Unlike a manual audit — which requires specialist time, access credentials, and days of effort — an online website security scanner runs in seconds and requires nothing beyond a URL.

Security scanning focuses on the hygiene layer: are your HTTP response headers correctly set? Is your TLS certificate valid and using strong cipher suites? Does your domain appear on any blocklists or malware databases? Are there sensitive files inadvertently accessible at predictable paths? These are the questions a security scanner is designed to answer quickly, repeatably, and at scale — whether you are protecting a single landing page or a portfolio of dozens of web properties.

In 2026, with AI-assisted development tools able to ship production applications in hours, the gap between “it works” and “it is secure” has never been more dangerous. Vuln0x closes that gap by making the security check as fast as the deployment.

How Vuln0x's website security scanner works

Vuln0x operates in two distinct stages, each serving a different need.

Stage 1 — Passive grade (free, no account). The moment you submit a URL, Vuln0x sends a small set of HTTP requests that replicate exactly what a browser or search-engine crawler would do. It analyses the response headers, TLS handshake, cookie attributes, redirect chain, and server banners. Within seconds you receive an A+ to F security grade along with a prioritised shortlist of the most impactful surface-level findings. Nothing is modified on your server; no intrusive probes are sent.

Stage 2 — Full 40+ engine scan (free account). Registering unlocks the deep scan, which runs more than 40 specialised engines in parallel. These cover header-policy analysis, SSL/TLS grading, JavaScript secret detection, CORS misconfiguration probing, malware and blocklist lookups, exposed-file discovery, clickjacking testing, open-redirect fuzzing, SSRF endpoint checks, and framework-specific modules for Next.js, React, WordPress, and others. The full scan typically completes in under 60 seconds and produces a unified report with severity ratings, remediation guidance, and SARIF/PDF/CSV exports.

What the online security scanner checks

Vuln0x's best-in-class online website security scanner covers the following surface areas in its passive grade, with the full scan adding application-layer checks:

HTTP security headers — Content-Security-Policy, Strict-Transport-Security, X-Frame-Options, Referrer-Policy, Permissions-Policy, and X-Content-Type-Options. Missing or misconfigured headers remain among the most common findings in 2026 security audits.
TLS / SSL configuration — expired certificates, weak cipher suites, TLS 1.0/1.1 support, mixed-content issues, and HSTS preload eligibility.
Malware and blocklist signals — whether the domain or IP appears on public threat-intelligence feeds, Google Safe Browsing, or known bad-actor registries. See the dedicated website malware scanner guide for a full explanation of what these checks cover and their limitations.
Misconfiguration detection — CORS wildcard origins, debug endpoints left enabled in production, directory listing, and permissive cross-origin policies.
Exposed files — source maps, .env files, backup archives, admin panels, and other paths that should never be publicly reachable.
Cookie security attributes — HttpOnly, Secure, and SameSite flags that protect session cookies from interception and cross-site attacks.

The full scan extends these with application-layer probes for XSS, SQL injection, SSRF, Log4Shell, clickjacking, and framework-specific CVEs. For a detailed breakdown of application vulnerability checks, see the website vulnerability scanner page.

Website security scanner vs vulnerability scanner — what is the difference?

The two terms are often used interchangeably in marketing copy, but they describe subtly different scopes of work.

A security scanner focuses on configuration correctness and hygiene. It answers questions like: “Are my headers set correctly?”, “Is my certificate valid?”, “Does my domain appear on a blocklist?”, and “Have I left sensitive files exposed?” These checks are generally non-intrusive — they observe what your server broadcasts rather than actively probing its logic.

A vulnerability scanner goes a step further into application logic. It actively probes endpoints with crafted payloads to discover exploitable flaws: XSS injection points, SQL injection in query parameters, SSRF via webhook URLs, Log4Shell via JNDI strings, and so on. This requires sending requests that look more like an attacker than a crawler, which is why responsible scanners always verify target ownership before running active checks.

Vuln0x's free passive grade is security-scanner-grade. The full scan combines both disciplines — giving you configuration hygiene analysis and application vulnerability probing in a single unified score and report. You do not need to choose between tools or piece together results from multiple sources.

Website security scanner API and CI/CD integration

For teams that need to scan automatically on every deployment, Vuln0x provides a REST API and a pre-built GitHub Actions integration. The API lets you submit scan targets programmatically, poll for results, and retrieve findings in JSON — making it easy to pipe Vuln0x output into your existing security dashboards, SIEM tools, or Slack notifications.

The GitHub Actions integration goes further: it submits a scan on every pull request, waits for results, and posts a pass/fail check to the PR status. If a new deployment introduces a missing security header or accidentally exposes a .env file, the check fails before merge — not after a customer reports it. Results are exported as SARIF and surface directly in the GitHub Security tab alongside any other code-scanning findings.

Full API documentation and workflow examples are available at /features/api-cicd.

Related security scanner guides

Explore the guides below to go deeper on specific topics — from malware and blocklist scanning to application vulnerability detection and CI/CD automation.

Frequently asked questions

Is there a free website security scanner API?: Yes. Vuln0x provides a REST API that lets you trigger scans programmatically and retrieve results in JSON. Free accounts receive 50 credits on signup — enough for 50 full scans — with no credit card required. API keys are available from your account dashboard, and pre-built GitHub Actions workflows make it straightforward to add a security scan gate to every pull request.
What is the difference between a security scanner and a vulnerability scanner?: The terms are often used interchangeably, but there is a practical distinction. A website security scanner focuses on configuration and hygiene signals — HTTP headers, TLS settings, blocklist status, exposed sensitive files, and misconfigurations that raise overall risk. A vulnerability scanner goes deeper into application logic, probing for exploitable flaws such as XSS, SQL injection, SSRF, and known CVEs. Vuln0x's free passive check is security-scanner-grade; the full 40+ engine scan covers both security configuration and application vulnerabilities.
What does Vuln0x's website security scanner check?: The passive surface check covers HTTP security headers (CSP, HSTS, X-Frame-Options, Referrer-Policy, Permissions-Policy), TLS certificate validity and cipher strength, cookie security attributes (HttpOnly, Secure, SameSite), blocklist and malware signals, and obviously exposed files such as .env or backup archives. The full scan adds 40+ deeper checks including XSS, SQL injection, CORS misconfigurations, and framework-specific CVEs.
How do I use Vuln0x as the best website security scanner for CI/CD?: Sign up for a free account to get your API key, then add the Vuln0x GitHub Action to your workflow YAML. The action submits a scan on every pull request, waits for results, and fails the check if the security score drops below your configured threshold. Results are exported as SARIF and posted directly to the GitHub Security tab. Full documentation is available at /features/api-cicd.
Is the website security scan safe to run on a live production site?: Yes. The passive check sends the same HTTP requests a browser or search-engine bot would send — it never modifies data or exploits vulnerabilities. The full scan's active probes are also designed to be non-destructive, but if you prefer, you can point Vuln0x at a staging environment first and compare results before running against production.

Ready to run a free website security scan?

Start free — 50 credits included, no credit card required. Get your first security grade in seconds.

Scan your website free