SafeLine: 21K Stars for a Self-Hosted Open Source WAF

Honestly, most solo site owners and small teams don’t take web security seriously until they’ve been attacked. I was the same way. Then someone scanned a few SQL injection vulnerabilities on one of my sites, and I realized how important it is to put a WAF in front of everything. That’s when I started looking at SafeLine.

Project Background

SafeLine is an open-source Web Application Firewall from Chaitin Tech, written in Go, with 21.2K stars on GitHub. Its positioning is clear: let users add security protection to their websites quickly through reverse proxy, without changing any business code.

Chaitin Tech has a solid reputation in China’s security community, coming from vulnerability scanning and penetration testing. Open-sourcing this WAF got a strong community response.

Core Capabilities

Reverse proxy deployment. You just point your domain to SafeLine, and SafeLine forwards traffic to your real backend server. Zero intrusion into business code, and you can set it up in minutes.

Rule-based protection. It can detect and block SQL injection, XSS, command injection, file inclusion, and common web vulnerabilities. The rule library updates automatically.

Bot management. It distinguishes normal users from crawlers, scanners, and malicious scripts. This is especially effective against attackers running automated tools against your site.

CC protection. You can set rate limits to prevent malicious traffic from overwhelming your backend. For small sites, this blocks a lot of low-cost DDoS attempts.

Visual dashboard. Attack logs, interception statistics, and traffic trends are all shown in charts. It’s a security tool, but it’s not confusing to use.

Quick Start

The easiest way is Docker one-command deployment:

curl -fsSL https://waf-ce.chaitin.cn/release/latest/setup.sh | bash

Or pull the image manually:

docker pull chaitin/safeline:latest

After installation, open the dashboard, add a site, fill in your backend address, and point your domain’s DNS to the SafeLine server. The flow is similar to configuring an Nginx reverse proxy.

Pros and Cons

Pros:

• Open source and free with an active community
• Simple deployment via Docker one-click install
• Zero intrusion into business code via reverse proxy
• Comprehensive rule library covering common web attacks
• Clear visual dashboard and logs
• Backed by Chaitin Tech’s security expertise

Cons:

• Free version has limited features; advanced features require commercial license
• Performance under extreme high traffic lags behind commercial WAFs
• Complex business scenarios may need manual rule tuning to avoid false positives
• Deployed on domestic servers, may add latency for overseas visitors
• Update pace slowed in the second half of 2025

Comparison

Tool	Open Source	Deployment	Rule Library	Dashboard	Best For
SafeLine	✅	Docker/Script	Good	✅	Solo sites, SMBs
ModSecurity	✅	Nginx/Apache module	Needs config	Weak	Strong tech teams
Cloudflare WAF	❌	DNS	Full	✅	Global businesses
Alibaba Cloud WAF	❌	DNS	Full	✅	Mid-large China businesses
OpenResty + Lua	✅	Self-built	Custom	None	Highly custom needs

If you don’t want to pay for a commercial WAF but need quick protection, SafeLine is one of the most hassle-free open-source options available right now.

Who Should Use It

Three scenarios fit well:

1. Solo site owners — blogs, small sites, open-source project homepages
2. Small and medium businesses — no dedicated security team but need basic protection
3. Developers learning — want to understand WAF principles and rule-based defense

I’ve used it for about three months. My main takeaway: it won’t make your site invincible, but it blocks 90% of routine scans and automated attacks. For a free security solution, that’s already a great deal.

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About the Author

Liudingyu is a full-stack developer and heavy GitHub user. With 900+ starred repos over the past 3 years, this site only covers tools I’ve actually used or deeply researched.

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