Coraza Web Application Firewall vs ModSecurity Open Source WAF

Coraza is the modern successor to ModSecurity. For new deployments, especially on cloud-native infrastructure, Coraza is the better starting point. For existing ModSecurity setups on Apache or Nginx that work fine, there is no urgent reason to migrate, but know that the future of open source WAF development is shifting toward Coraza.

View Coraza Web Application Firewall Review View ModSecurity Open Source WAF Review

Overview

Coraza and ModSecurity are both open source WAF engines that run the same OWASP Core Rule Set (CRS) and speak the same rule language (SecLang). But they come from very different eras. ModSecurity was created in 2002 by Ivan Ristic, making it the original open source WAF. Coraza arrived in 2021 as a ground-up rewrite in Go, designed to be the modern successor.

This is not a case of two competing products with different philosophies. Coraza was built specifically to replace ModSecurity. It uses the same rule format, runs the same CRS rules, and targets the same use case. The question is not whether Coraza is better in theory, but whether it is ready for your specific deployment today.

Understanding the history matters here. ModSecurity started as an Apache module, was maintained by Trustwave from 2010 to 2024, and is now a community-driven OWASP project. The v3 rewrite (libmodsecurity) decoupled it from Apache and added Nginx support via connectors. But development has slowed significantly since Trustwave handed it over.

Coraza, meanwhile, was created by Juan Pablo Tosso and quickly became an official OWASP project. Written in pure Go with zero C dependencies, it was designed for the cloud-native world: embeddable as a library, deployable as a plugin for Caddy, Traefik, HAProxy, or Envoy (via proxy-wasm). The OWASP CRS project now tests against both engines, and CRS v4 explicitly lists Coraza as a supported WAF engine alongside ModSecurity v2 and v3.

Quick Comparison

Feature Coraza Web Application Firewall ModSecurity Open Source WAF
Overall Rating 4.2/5 4.0/5
Free Tier Yes Yes
Pricing Model Free and open source (Apache 2.0) Free (Open Source)
Ease of Use 3.8/5 2.5/5
Value for Money 4.8/5 4.8/5
Support 3.5/5 3.0/5
Open Source Yes Yes
Platforms Any platform running Go, Docker, Kubernetes, Linux, macOS, Windows Apache, Nginx, IIS, Kubernetes (via Ingress), Docker, any platform via libmodsecurity
Compliance Supports PCI DSS compliance when configured with OWASP CRS N/A (varies by implementation)

Pricing Comparison

Coraza Web Application Firewall

Model: Free and open source (Apache 2.0)

Free Tier Available

Open Source

Free

View full pricing →

ModSecurity Open Source WAF

Model: Free (Open Source)

Free Tier Available

Community Edition

Free

Commercial Support

Varies by vendor

View full pricing →

Features Comparison

Coraza Web Application Firewall

  • ModSecurity Compatibility

    Full compatibility with ModSecurity SecLang rule language. Existing ModSecurity rules and rule sets work without modification.

  • OWASP CRS Support

    Native support for the OWASP Core Rule Set, providing protection against SQL injection, XSS, RCE, and other OWASP Top 10 threats.

  • Go Native

    Pure Go implementation with no C dependencies. Embeddable as a library, usable as middleware, or deployable as a plugin for modern proxies.

  • Proxy Plugins

    Official plugins for Caddy (coraza-caddy), Traefik, and HAProxy allow adding WAF protection with minimal configuration.

  • Kubernetes Ready

    Lightweight enough to run as a sidecar or embedded in ingress controllers. Works with any Go-based K8s tooling.

  • Audit Logging

    Detailed audit logging of blocked and flagged requests for security analysis and compliance reporting.

ModSecurity Open Source WAF

  • OWASP Core Rule Set

    Comprehensive, community-maintained rule set providing protection against OWASP Top 10 and more.

  • Custom Rules

    Powerful SecRule language for creating custom detection logic based on any request/response attribute.

  • Real-Time Request Analysis

    Inspect and analyze every HTTP transaction with access to full request and response data.

  • Audit Logging

    Detailed logging of security events for forensics, compliance, and monitoring.

  • Virtual Patching

    Create temporary rules to protect against vulnerabilities while permanent fixes are developed.

  • Data Loss Prevention

    Inspect response bodies to prevent sensitive data leakage.

Which One Is Right for You?

The best WAF depends on your specific requirements, infrastructure, and team expertise.

Coraza Web Application Firewall

Choose Coraza when:

  • You are starting a new WAF deployment from scratch and want a modern foundation
  • You run Caddy, Traefik, or Envoy as your reverse proxy
  • You deploy on Kubernetes and want a WAF that fits the cloud-native model (sidecar, embedded, proxy-wasm)
  • You want a Go library you can embed directly into your application or custom proxy
  • You care about build simplicity: no C compiler, no libxml2, no libpcre dependencies
  • You want to use CRS v4 with a WAF engine that is actively maintained and improving
Learn more →

ModSecurity Open Source WAF

Choose ModSecurity when:

  • You have an existing, tuned ModSecurity deployment on Apache or Nginx that is working well
  • You run Apache httpd and want the most mature, battle-tested WAF module for it
  • You need the Nginx connector (ModSecurity-nginx), which is more mature than Coraza's Nginx story
  • You need IIS support, which Coraza does not offer
  • Your organization has deep institutional knowledge of ModSecurity internals and debugging
  • You depend on specific ModSecurity v2 features or behaviors that Coraza does not yet implement
Learn more →

We recommend evaluating both options with a trial or free tier before committing. Consider your existing infrastructure, team expertise, compliance requirements, and budget.

Frequently Asked Questions

Is Coraza a fork of ModSecurity?

No. Coraza is a complete rewrite from scratch in Go. It was not forked from ModSecurity's C/C++ codebase. The only thing they share is compatibility with the SecLang rule language, which means existing ModSecurity rules (including the OWASP Core Rule Set) work on both engines. Think of it as a clean-room reimplementation of the same specification.

Can I migrate from ModSecurity to Coraza without rewriting my rules?

In most cases, yes. Coraza supports the ModSecurity SecLang rule language and is 100% compatible with OWASP CRS v4. Your CRS rules and most custom SecLang rules will work without modification. However, Coraza has "partial compatibility" with some advanced ModSecurity features, so if you use highly specialized custom rules, test them before switching. The core CRS rules are fully tested against Coraza on every release.

Is ModSecurity dead?

No, but development has slowed. After Trustwave transferred ModSecurity to the OWASP community, the project continues to receive maintenance updates and bug fixes. ModSecurity v3 (libmodsecurity) is the current version and still gets commits on GitHub. However, the pace of new feature development is much slower than Coraza's, and the contributor base is smaller than it was during the Trustwave era. ModSecurity is not abandoned, but it is no longer where the momentum is.

Which WAF engine does the OWASP CRS project recommend?

The CRS project does not officially recommend one engine over the other. CRS v4 explicitly supports ModSecurity v2, ModSecurity v3, and Coraza. The CRS CI pipeline tests against all three. That said, the CRS v4 migration guide and documentation increasingly treat Coraza as a first-class engine, and several CRS maintainers are also active Coraza contributors.

Does Coraza work with Nginx?

Not as a native Nginx module like ModSecurity-nginx. Coraza does not have a direct Nginx connector. The typical approach is to run Coraza as a reverse proxy in front of Nginx (using Caddy or HAProxy with the Coraza plugin), or to use it as a proxy-wasm filter in Envoy. There is also an experimental libcoraza project (C bindings) that could enable an Nginx module in the future, but it is not production-ready. If you need a native Nginx WAF module today, ModSecurity is still the better option for that specific use case.

Which is faster, Coraza or ModSecurity?

Coraza generally shows competitive or better performance than ModSecurity v3 in benchmarks, particularly for high-concurrency workloads where Go's goroutine model shines. ModSecurity v3 can be faster for single-threaded rule evaluation in some scenarios due to its C implementation. In practice, the performance difference rarely matters more than your rule set complexity and the number of rules enabled. Both engines add single-digit millisecond overhead for typical CRS configurations.

What happened to Trustwave and ModSecurity?

Trustwave maintained ModSecurity from roughly 2010 to 2024 and provided commercial rules and support. In January 2024, Trustwave transferred ModSecurity to the OWASP Foundation, making it a fully community-driven project. Trustwave discontinued their commercial ModSecurity products (including their commercial rule feed). This transition was a major factor in Coraza gaining traction, as organizations looking for long-term open source WAF support increasingly saw Coraza as the safer bet.

Can I use Coraza with Kubernetes?

Yes, and this is one of Coraza's strongest use cases. As a Go library, it can be embedded into ingress controllers, run as a sidecar container, or deployed as proxy-wasm middleware in Envoy-based service meshes. The Caddy plugin (coraza-caddy) is popular for Kubernetes ingress. ModSecurity can also run in Kubernetes (usually via the Nginx Ingress Controller with ModSecurity enabled), but the setup is heavier and less flexible.