Let's Encrypt
Free, automated TLS certificates to enable HTTPS on your sites
Code scanners, secrets and password managers, and web security tools.
73 tools

Free, automated TLS certificates to enable HTTPS on your sites

Crowdsourced bug bounty and penetration testing platform

Open source encryption for files stored in cloud drives

Cloud scanner for exposed assets, APIs and web applications

Self-hosted, open source server for a Tailscale network

Open source cookie consent manager for GDPR-focused websites


Open source CLI that finds known vulnerabilities in container images

Open source Kubernetes security scanner and policy checker


General-purpose policy engine that decouples policy from code

Open source tools for signing and verifying software artifacts

Cloud and AI security platform linking code, cloud and runtime

Security platform for code, dependencies, cloud and pentests

Enterprise platform that scans code for security flaws and risks

Code analysis engine that runs security queries across a codebase

Platform that finds exposed secrets and credentials in code

Finds leaked passwords and API keys in git repositories

Stores and controls access to secrets, keys and certificates

Finds known vulnerabilities in your project's dependencies

Scans source code and dependencies for security issues

Finds security risks in AI-written code, agents and apps

Checks code quality and security in every change, human or AI

Open source scanner for vulnerabilities and misconfigurations

Open source scanner for leaked secrets, with live verification

Platform for finding and fixing application security risks

Cookie consent banner and scanner for GDPR and CCPA compliance

Lightweight vanilla JavaScript cookie consent plugin for websites

Open source cookie consent manager for GDPR-focused websites

Privacy policy generator, cookie consent and compliance tools

Compliance automation for SOC 2, ISO 27001, HIPAA and more

Open source encryption for files stored in cloud drives

DMARC management platform with free domain and record checker tools

Online DNS, mail server and blacklist lookup tools

Private encrypted messenger for text, voice and video calls

Encrypted email, calendar and contacts with a free plan

Free open source disk encryption for Windows, Mac and Linux

Open source 2FA authenticator with end-to-end encrypted backups

Offline, open source password manager for Windows, Mac and Linux

Open source fork of HashiCorp Vault for managing secrets

End-to-end encrypted password manager with email aliases

Hardware security key for phishing-resistant two-factor sign-in


Open source reverse proxy WAF that protects web services

Invisible, privacy-friendly CAPTCHA that uses proof-of-work

Privacy-focused CAPTCHA and bot detection for sites and apps

Self-hosted, open source server for a Tailscale network


Open source proof-of-work CAPTCHA that does not track users

Open source web application firewall engine used with OWASP rules

Open source zero trust network access built on WireGuard

Go-based open source web application firewall with CRS support

Identity-aware access proxy for private apps, SSH and Kubernetes

VPN with a free plan, open source apps and a no-logs audit


Website security service for malware cleanup and firewall



Crowdsourced bug bounty and penetration testing platform

Web security testing toolkit for manual and automated scanning

Platform for bug bounties and vulnerability disclosure programs

Free, open source network scanner for hosts, ports and services

Hands-on cyber labs, challenges and training for teams and learners

Short security guides for developers, one topic per sheet

Nonprofit hub for free application security projects and standards

Deliberately insecure web app for security training and CTFs

Browser-based hands-on cyber security labs and guided paths

Free online web security training with interactive labs

Cloud scanner for exposed assets, APIs and web applications

Open source scanner that runs vulnerability checks from templates

Search engine that indexes internet-connected devices and services

Security testing for running apps, with fixes from coding agents

Command line tool that tests TLS and SSL server configurations


Check if your email or password appeared in a known data breach

Free, automated TLS certificates to enable HTTPS on your sites

Free open source scanner for finding security flaws in web apps