One platform.
Every vulnerability.
Free scans. AI-powered analysis. Continuous monitoring. Browser extension. 11,000+ security checks. All in one place.
A library of 11,000+ focused, single-purpose scans targeting specific CVEs, technologies, and configuration weaknesses. Every feature on this page is powered by this engine.
New CVEs, covered
within hours.
S4E monitors the global vulnerability landscape daily and ships scanner support as new CVEs emerge so your assets are checked before attackers can exploit them.
See all CVE scanners →Describe it.
AI scans it.
No coding needed. Describe what you want to test the AI generates the exact code, executes it on the S4E engine, and delivers real-time results you can review, tweak, and re-run.
Check if our checkout page leaks card data to 3rd-party scripts, and verify session tokens expire after password reset.
I've generated a targeted scan based on your requirements. Here's what I created:
import requests from bs4 import BeautifulSoup def check_pci_leak(url): """Check outbound requests for PCI data""" resp = requests.get(url, timeout=10) soup = BeautifulSoup(resp.text, "html.parser") scripts = [ src["src"] for src in soup.find_all("script", src=True) ] return { "third_party": scripts, "risk": "HIGH" if len(scripts) > 5 else "LOW" }
Scans that
never stop.
Schedule recurring scans across your entire attack surface. The Scheduler runs 24/7 new subdomains, expired certificates, open ports, fresh CVEs. You get notified, not surprised.
Start continuous monitoring →Security intel,
always one tab away.
Install the S4E extension and scan from the tab you're already on. Save your session for authenticated scans, collect attack surface as you browse, and set crawl include/exclude rules without leaving the page.
Add to Chrome Free →Plug S4E
into your stack.
REST API, MCP protocol, webhooks, CI/CD pipelines. Build security into your workflow programmatically trigger scans, consume results, and automate remediation.
Read API docs →REST API
Full programmatic access to scans, results, assets, and reports.
MCP Protocol
Connect S4E to AI agents and LLM workflows as a tool provider.
CI/CD
Run security checks in your deployment pipeline. Block on critical findings.
Built with the community.
Tools we've built, projects we sponsor, and services that extend the S4E ecosystem.
Spark
GitHubReal-time security alert client. Monitors your assets continuously and fires notifications the instant a new vulnerability appears, a port opens, or a certificate expires.
View on GitHub →Playbooks
GitHubPre-built scan sequences for compliance, pentest, and reconnaissance. PCI-DSS, ISO 27001, full attack surface mapping select a goal, hit run, S4E does the rest.
View on GitHub →Labs
Open SourceNuclei top contributor, Wapiti sponsor, open access research, whitepapers and anonymized data for the security community.
Explore Labs →Start free.
Scale when ready.
No credit card. No commitment. Just sign up and scan.