Best Free Open-Source Security Software

Private, end-to-end encrypted messaging.

Comprehensive authentication framework

Secure dotenv for developers

Cross-platform password manager compatible with Keepass 2.x

Simple vaultless password manager in Go

An open platform for various uses

Secure and fast microVMs for serverless computing

Distributed operating system for blockchain app builders

Secure, Simple and Scalable Video Conferences

Open-source antivirus engine for detecting malware across platforms

Bitwarden‑compatible vault hosted on Cloudflare Workers for free

Patch-level verification for Bundler

Open source password manager for teams

Automate cloud security and compliance

Advanced offline password cracker supporting hundreds of hash types

Interactive, scriptable man‑in‑the‑middle proxy for HTTP, HTTPS and WebSocket traffic

Single Sign-On Multi-Factor portal for web apps

Unified XDR and SIEM protection for endpoints and cloud workloads

Free, open-source password manager

Run data science on remote data without moving it.

Fast and lightweight DNS proxy as ad-blocker for local network

Automate OSINT for threat intelligence and attack surface mapping

Secure, fast file transfers from the command line

A note-taking app with a focus on security and simplicity