The Best Open-Source Alternatives to KnowBe4
Are you looking for a free or self-hosted alternative to KnowBe4? In 2026, avoiding expensive proprietary software subscriptions is easier than ever. The open-source community has built excellent privacy-friendly tools within the Security ecosystem. Currently, there are 4 active replacements available, with Gophish being one of the most prominent selections.
Quick Comparison: KnowBe4 vs. Open Source
Full comparison: KnowBe4 vs. Gophish →| Criteria | KnowBe4 | OSS Replacements |
|---|---|---|
| Pricing model | Paid / Monthly Fees | 100% Free / Self-Hosted |
| Data Control | Third-party Servers | Full Ownership & Privacy |
| Customizability | Restricted by Vendor | Unlimited (Modify Codebase) |
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Gophish
Gophish is a highly customizable, cross-platform phishing simulator that empowers organizations to educate employees and conduct threat assessments in a risk-free environment, offering a privacy-friendly alternative to commercial platforms like KnowBe4. This free and open-source solution allows IT professionals to create realistic phishing campaigns, track engagement, and refine security awareness training without compromising user data or financial resources.
Mailpit
Mailpit is a lightweight, privacy‑first email testing server that captures outgoing emails locally in an in‑browser UI, allowing developers to preview, search, and analyze messages without sending them externally. Its open‑source nature, zero‑tracking architecture, and zero‑dependency design make it an ideal, privacy‑friendly alternative to commercial solutions like KnowBe4 for secure phishing awareness and email testing.
King Phisher is a free and open-source phishing simulator that helps organizations educate employees about phishing tactics without compromising security or exposing sensitive data, a more privacy-friendly alternative to commercial solutions like KnowBe4. This tool enables controlled testing of phishing campaigns while preserving user trust and maintaining regulatory compliance.
FiercePhish is a lightweight, privacy‑centric open‑source phishing training platform that automates the creation, delivery, and reporting of realistic spear‑phishing simulations without storing personal data in the cloud. It offers organizations a transparent, self‑hosted alternative to proprietary solutions like KnowBe4, giving full control over content, metrics, and user data while maintaining rigorous security and compliance standards.
Frequently Asked Questions
What is the best open source alternative to KnowBe4?
Based on GitHub community data (including star count and fork activity), Gophish stands out as one of the most reliable open-source replacements for KnowBe4 today.
Why should I use an open-source replacement instead of KnowBe4?
Switching to an open-source solution ensures complete data sovereignty, protects your software environment from sudden vendor price hikes, and gives you full transparent control over your tech-stack metadata.