Best Open Source Application Security Software
Browse 14 production-ready, self-hostable open-source tools in Application Security. Eliminate per-seat SaaS costs, retain complete data ownership, and claim $100K+ in startup cloud hosting credits.
Top Open-Source Application Security Software Compared
Direct overview of top-ranked solutions by community stars and license
| Tool Name | GitHub Stars | License | Replaces Proprietary | Details |
|---|---|---|---|---|
| GrowthBook | ★ 13,923 | MIT | LaunchDarkly, ConfigCat | View Stack → |
| Flagsmith | ★ 13,923 | BSD-3-Clause | LaunchDarkly, ConfigCat | View Stack → |
| Abby | ★ 13,923 | AGPL-3.0 | LaunchDarkly, ConfigCat | View Stack → |
| FeatBit | ★ 13,923 | MIT | LaunchDarkly, ConfigCat | View Stack → |
| Featurevisor | ★ 13,923 | MIT | LaunchDarkly, ConfigCat | View Stack → |
All 14 Application Security Open Source Tools
Ranked by GitHub community stars & active adoption
GrowthBook
MITPowerful, developer-friendly experimentation tool for data-driven product decisions. Seamless integration, real-time insights, and flexible deployment.
Flagsmith
BSD-3-ClausePowerful feature management platform for seamless software releases, A/B testing, and personalized user experiences.
Abby
AGPL-3.0Abby offers open-source, fully typed feature flagging and remote configuration for React and Next.js, with multi-environment testing and debugging tools.
FeatBit
MITFeatBit is a fast, scalable feature flag service that enables risk mitigation and fosters business growth through controlled feature releases.
Featurevisor
MITFeaturevisor is an open-source tool for managing feature flags, experiments, and remote configuration directly from your Git repository.
Flipt
GPL-3.0A feature flag platform that integrates with Git workflows, enabling developers to manage features directly in their codebase.
Unleash
AGPL-3.0A powerful feature management platform enabling gradual rollouts, A/B testing, and seamless integration for continuous delivery.
ALTCHA
MITALTCHA offers cutting-edge spam and abuse protection for websites and apps, with privacy-friendly CAPTCHA alternatives designed for GDPR compliance.
Cap
Apache-2.0Lightweight open-source CAPTCHA solution using SHA-256 proof-of-work. 250x smaller than hCaptcha, fully customizable, and privacy-focused with zero telemetry.
mCaptcha
AGPL-3.0Privacy-focused proof-of-work CAPTCHA system that silently protects websites without tracking users or requiring image solving. Drop-in replacement for…
Procaptcha
Apache-2.0A blockchain-based CAPTCHA solution offering improved security, user experience, and resistance to bot attacks for web applications.
Private Captcha
Open SourcePrivacy-first CAPTCHA service that blocks bots while keeping forms accessible. No puzzles, no tracking, no cookies - just invisible cryptographic protection.
Friendly Captcha
MPL-2.0Privacy-compliant CAPTCHA alternative using proof-of-work technology. Protects websites from bots and spam without user interaction or data tracking.
OneHuman
BUSL-1.1Detects AI agents using customer credentials, masks private fields, holds risky actions for passkey approval, and signs every decision on your own server.
Frequently Asked Questions: Open Source Application Security
What are the best open source Application Security tools in 2026?
The highest-ranked open-source software in Application Security is GrowthBook with over 13,923 GitHub stars. Other leading tools include Flagsmith, Abby, FeatBit, Featurevisor. All are vetted for production self-hosting.
Can I self-host Application Security open source tools on my own cloud?
Yes. Tools listed in this category support self-hosting via Docker, Docker Compose, Kubernetes, or Helm on AWS, Google Cloud, DigitalOcean, Hetzner, or bare metal with zero per-seat licensing fees.
How can early-stage startups get free cloud credits to host Application Security tools?
Founders can claim up to $100,000 in AWS Activate, $350,000 in Google Cloud for Startups, and $1,000 in DigitalOcean credits via Startupbricks Perks (startupbricks.in/perks) to deploy self-hosted stacks at zero infrastructure cost.
What proprietary SaaS does open source Application Security software replace?
Open-source tools in this category replace proprietary commercial platforms including LaunchDarkly, ConfigCat, Optimizely, Hypertune, Bucket, Statsig, Tggl, reCAPTCHA, Cloudflare Turnstile, hCaptcha. Switching gives your team 100% data custody, security control, and zero recurring seat costs.
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