SafeLine

SafeLine is a web application firewall (WAF) that sits in front of your servers and filters malicious requests: SQL injection, XSS, bot traffic, credential stuffing. It's a bouncer for your web traffic that inspects every request before it reaches your app.

GPL v3, Go. Uses a semantic analysis engine (not just regex pattern matching) to detect attacks, which means lower false positives than traditional WAFs. Dashboard shows traffic stats, blocked threats, and lets you configure rules. Supports reverse proxy mode. Drop it in front of Nginx or any web server.

The community edition is free. Docker install, configure your upstream servers, and it's running. Basic WAF protection, bot detection, rate limiting, and IP blocking included. A pro/enterprise version exists with advanced features like enhanced bot protection, API security, and priority support. Pricing isn't publicly listed. Contact sales. Solo developers: free community edition is solid for protecting personal projects and small apps. Small teams: free edition handles most threats. Medium to large: evaluate the pro version for advanced bot protection and API security, or consider Cloudflare WAF if you're already using their CDN.

The catch: you're adding another hop in your request chain. Latency increases slightly. The community edition's rule set is less comprehensive than Cloudflare or AWS WAF. And the GPL v3 license means modifications must be open-sourced, which matters if you're integrating it deeply into proprietary infrastructure.