Best WAF for Free WAF
Every genuinely free WAF option in one place. Open source server-level firewalls, cloud WAFs with free tiers, and WordPress security plugins. Covers the difference between network and application layer protection, with honest assessments of what free gets you.
ModSecurity Open Source WAF
ModSecurity with OWASP CRS is the most widely deployed free WAF in the world, protecting millions of sites through hosting providers, CDNs, and direct installs. Completely free, fully featured, and backed by a decade of community-maintained rules.
Free does not mean weak. Some of the most battle-tested WAFs in production today cost nothing. ModSecurity protects millions of sites through shared hosting providers. Cloudflare's free tier handles DDoS attacks that would take down unprotected servers. NAXSI has been quietly filtering bad requests on NGINX since 2011. The catch is not the price. It is knowing which type of free WAF fits your setup.
Network layer vs application layer: why it matters for WAFs
A network-layer firewall (L3/L4) filters traffic by IP address, port, and protocol. It can block entire countries, rate-limit connections, and stop volumetric DDoS. But it cannot read the contents of an HTTP request. It does not know if a POST body contains SQL injection or if a URL parameter is a path traversal attempt.
A web application firewall (L7) inspects the actual HTTP request: headers, query strings, POST bodies, cookies, and JSON payloads. It understands that SELECT * FROM users in a form field is an attack, not a search query. Every WAF on this page operates at Layer 7.
Some solutions combine both. Cloudflare provides L3/L4 DDoS protection alongside its L7 WAF rules. BunkerWeb bundles NGINX with ModSecurity rules, rate limiting, and IP reputation in one package. CrowdSec adds community-driven IP blocklists (network layer) on top of its application-layer behavior analysis.
Three categories of free WAFs
This page covers every genuinely free WAF we list, organized into three groups:
- Open source server-level WAFs that you self-host. Unlimited features, full control, zero cost. You handle setup and maintenance.
- Cloud WAFs with free tiers that work instantly via DNS. Limited features, but zero setup and zero server access needed.
- WordPress security plugins with free firewall features. Install from the plugin directory and activate. Some are surprisingly capable.
Quick Comparison
| Provider | Rating | Free Tier | Best For |
|---|---|---|---|
| 4.0/5 | Security teams with WAF expertise, organizations … | ||
| 4.2/5 | Teams migrating from ModSecurity, Kubernetes envi… | ||
|
3
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3.4/5 | Teams already running NGINX who want lightweight … | |
| 4.0/5 | Security-conscious organizations wanting data con… | ||
| 4.3/5 | |||
| 4.1/5 | Kubernetes environments, teams using NGINX or Kon… | ||
| 4.1/5 | Self-hosted deployments wanting easy setup, teams… | ||
| 4.0/5 | High-traffic sites requiring maximum performance,… | ||
| 4.5/5 | Small to medium websites, WordPress sites, develo… | ||
| 4.4/5 | WordPress site owners, bloggers, small businesses… | ||
| 4.3/5 | WordPress site owners wanting affordable server-l… | ||
|
12
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4.0/5 | WordPress site owners wanting the absolute lighte… | |
| 3.9/5 | WordPress site owners wanting a simple, low-overh… | ||
| 3.9/5 | Budget-conscious WordPress site owners, beginners… | ||
| 4.0/5 | WordPress site owners wanting an all-in-one solut… | ||
| 3.8/5 | WordPress site owners wanting automated hands-off… | ||
| 4.1/5 | WordPress agencies managing multiple sites, users… | ||
| 3.7/5 | WordPress agencies needing affordable security fo… | ||
| 4.0/5 | WordPress site owners wanting malware scanning wi… |
Our Top Picks for Free WAF
The original open source WAF and still the most widely deployed. ModSecurity with OWASP Core Rule Set is the gold standard for free web application protection. Runs on Apache and NGINX, protects any web application regardless of framework. The CRS rules are maintained by a dedicated community and cover OWASP Top 10 attacks out of the box. The tradeoff is setup complexity: you need server access and willingness to tune rules for your application.
The modern successor to ModSecurity, written in Go. Runs the same OWASP CRS rules but with better performance, native Kubernetes support via Envoy/Istio integration, and active development. If you are starting fresh with a self-hosted WAF in 2026, Coraza is the better foundation. ModSecurity's original maintainer (Trustwave) handed off the project; Coraza is where the momentum is.
NAXSI takes a fundamentally different approach: instead of pattern-matching known attacks (like ModSecurity/CRS), it uses a positive security model that blocks anything that does not match expected patterns. This means fewer false negatives but more tuning required. Built specifically for NGINX, maintained by founder Thibault Koechlin since 2011. If you want a lean, focused WAF that is not trying to be a security suite, NAXSI is it.
BunkerWeb bundles NGINX, ModSecurity, CrowdSec integration, Let's Encrypt, rate limiting, and a web UI into a single Docker image. It is the easiest way to get a full self-hosted security stack running without editing config files. Founded by Florian Pitance, it is a genuine open source project with an optional Pro support tier. Best pick if you want server-level WAF protection without the typical NGINX/ModSecurity configuration pain.
CrowdSec combines application-layer behavior analysis with community-driven IP reputation. The free tier includes a shared blocklist fed by thousands of installations worldwide, giving you collective threat intelligence at zero cost. Integrates with NGINX, Apache, HAProxy, and WordPress. The WAF component (AppSec) adds HTTP request inspection on top of the behavioral engine.
open-appsec uses machine learning instead of regex rules, which means it can detect novel attack patterns without signature updates. The open source edition includes the ML engine, NGINX/Kong integration, and automatic model updates. A genuinely different approach to WAF that avoids the false-positive tuning cycle of rule-based systems.
SafeLine uses semantic analysis to understand HTTP request intent rather than pattern matching. The free community edition includes the full WAF engine with a web dashboard, certificate management, and rate limiting. Chinese origin (Chaitin Tech) but fully functional in English. Good option if you want a self-hosted WAF with a polished UI and do not want to configure ModSecurity rules by hand.
Tempesta FW operates as a Linux kernel module, filtering traffic before it reaches userspace. This gives it raw performance that no userspace WAF can match. Completely free and open source. Best suited for high-traffic sites where per-request overhead matters. The tradeoff is a steeper learning curve and Linux-only deployment.
Cloudflare's free tier is the easiest WAF to deploy: change your DNS, and you get L7 WAF rules, DDoS protection, SSL termination, and CDN caching at zero cost. The free WAF covers OWASP Top 10 attacks and managed rulesets. Limitations: no custom WAF rules on free (you need Pro at $20/mo for that), limited bot management, and you are routing all traffic through Cloudflare's network. For most personal sites and small businesses, the free tier is genuinely sufficient.
The most installed WordPress security plugin with 5+ million active installs. The free tier includes a real endpoint WAF with WordPress-aware rules, malware scanning, 2FA, and brute force protection. The main limitation is a 30-day delay on new firewall rules compared to Premium users. For most WordPress blogs and small business sites, the free tier is genuinely good enough.
NinjaFirewall hooks into PHP before WordPress loads, giving it the ability to block malicious requests earlier than any other WordPress plugin. The free edition includes real-time rule updates (unlike Wordfence's 30-day delay), file integrity monitoring, and event logging. Lighter footprint than Wordfence with arguably better WAF architecture.
The lightest WordPress firewall in existence: under 10KB, zero configuration, zero settings page. BBQ is a PHP port of Jeff Starr's battle-tested 7G/8G Apache firewall rules. Install, activate, done. It does one thing (block bad requests) and does it well. A founder-led open source project maintained with care for over 15 years. If you want WordPress WAF protection with absolute minimum overhead, this is it.
Security Ninja includes a free 8G-based firewall plus 50+ security configuration tests and a vulnerability scanner. The WAF works immediately on activation with no configuration needed. Good choice if you want basic firewall protection plus a thorough security audit of your WordPress setup in one free plugin.
All-In-One Security provides one of the most feature-rich free WordPress security plugins available. The PHP-based firewall with 6G blacklist rules, user security scoring, login lockdown, and extensive hardening features are nearly all available without paying. From the team behind UpdraftPlus.
Built by Automattic (WordPress.com creators), Jetpack WAF benefits from threat intelligence gathered across millions of WordPress.com sites. The free tier includes automatic WAF rules and brute force protection. Rules are updated based on real attack data from the WordPress.com network.
Shield Security uses SilentCAPTCHA and an automatic IP reputation system for hands-off bot protection. The free tier includes the AntiBot Detection Engine that blocks malicious visitors without CAPTCHA challenges or admin intervention. Good for site owners who want automated protection without managing rules.
Solid Security (formerly iThemes Security) integrates Patchstack virtual patching in its free tier, automatically protecting against known plugin and theme vulnerabilities. Passwordless login with passkeys puts it ahead on authentication security. 15+ year track record under the iThemes name.
BulletProof Security provides .htaccess-based firewall protection in its free edition. The one-click setup wizard configures Apache-level rules without manual editing. Database backup and security logging are included free. The Pro version is a one-time $69.95 lifetime license if you ever need to upgrade.
MalCare's free tier includes basic firewall protection and login protection. Its unique selling point is cloud-based malware scanning: the scanning happens on MalCare's servers, so zero performance impact on your site. Limited compared to the paid version but useful as a lightweight free layer.
How We Selected These Providers
Every WAF on this page meets at least one of these criteria:
- Fully open source with no feature restrictions (ModSecurity, Coraza, NAXSI, BunkerWeb, open-appsec, SafeLine, Tempesta FW, CrowdSec)
- Free cloud tier with meaningful WAF protection, not just a marketing landing page (Cloudflare)
- Free WordPress plugin with actual firewall functionality, not just security scanning (Wordfence, NinjaFirewall, BBQ, Security Ninja, AIOS, Jetpack, Shield, Solid, BulletProof, MalCare)
We excluded providers that offer "free trials" or require a credit card. If you have to pay eventually to keep protection active, it is not free.
Frequently Asked Questions
Are free WAFs actually effective against real attacks?
Yes. ModSecurity with OWASP CRS is used by major hosting providers (cPanel, Plesk, CloudLinux) to protect millions of shared hosting accounts. Cloudflare's free WAF handles billions of requests daily. Our own CRS regex research found that CRS at Paranoia Level 1 catches the majority of common web attacks out of the box, and we contributed 17 PRs to improve detection further.
The gap between free and paid is not detection quality. It is operational convenience: managed rule updates, dashboards, support SLAs, compliance reporting, and bot management. If you can handle setup and tuning yourself, a free WAF protects just as well as a paid one against standard web attacks.
What is the difference between a network firewall and a WAF?
A network firewall (L3/L4) filters by IP address, port, and protocol. It can block entire IP ranges or rate-limit connections, but it cannot see what is inside an HTTP request. A web application firewall (L7) reads the actual request content: URL parameters, POST bodies, headers, cookies, and JSON payloads. It detects attacks like SQL injection, XSS, and path traversal by inspecting request data.
Example: a network firewall can block all traffic from a suspicious IP. A WAF can block a specific request from any IP that contains UNION SELECT in a form field. You need both layers for comprehensive protection. Most cloud WAFs like Cloudflare combine both. Self-hosted WAFs like ModSecurity focus on L7 and assume you have a network firewall (iptables, cloud security groups) handling L3/L4.
Which free WAF is easiest to set up?
For any website: Cloudflare free tier. Change your DNS nameservers and you get WAF + DDoS + CDN. No server changes, no configuration files, takes about 10 minutes.
For WordPress: BBQ Firewall or Security Ninja. Both work immediately on activation with zero configuration. BBQ is the lighter of the two (under 10KB, no settings page). Security Ninja adds 50+ security tests on top of its firewall.
For self-hosted servers: BunkerWeb. One Docker command gets you NGINX + ModSecurity + CrowdSec + Let's Encrypt + web UI. Everything else (ModSecurity standalone, Coraza, NAXSI) requires manual server configuration.
What is the best free WAF for WordPress?
Depends on what you prioritize:
- Deepest protection: Wordfence free. WordPress-aware rules that understand user sessions, plugin states, and authentication. 30-day rule delay on free.
- Best architecture: NinjaFirewall free. Hooks into PHP before WordPress loads, so it blocks attacks earlier in the request lifecycle. Real-time rule updates even on free.
- Lightest footprint: BBQ Firewall. Under 10KB, zero config, zero overhead. Just pattern-matches known bad requests.
- Most features bundled: AIOS. Nearly everything free: firewall, login lockdown, file monitoring, security scoring.
For the full comparison, see our best WAF for WordPress guide with all 11 WordPress WAFs ranked.
What is the catch with free WAF services?
Cloud free tiers (Cloudflare): you get managed WAF rules but cannot create custom rules. Bot management, API protection, and advanced analytics require paid plans. You are also routing all traffic through their network, which some organizations prefer not to do.
Open source WAFs (ModSecurity, Coraza, NAXSI): no feature limits, but you are responsible for setup, tuning, updates, and false positive management. There is no vendor support hotline. When something breaks at 3 AM, you fix it yourself or pay for professional services.
WordPress plugins: free tiers often delay threat intelligence (Wordfence: 30 days), limit advanced features to paid versions (country blocking, malware scanning), or offer only basic rule sets. The free firewall is real, but the upsell is always visible.
Can I use a free WAF for a production ecommerce site?
Yes, with caveats. Cloudflare free tier protects thousands of small ecommerce sites. ModSecurity/CRS handles production traffic at any scale. It is what most shared hosting providers use.
For PCI-DSS compliance, free WAFs work technically but you lose the compliance documentation, audit trails, and vendor support that auditors expect. Most PCI assessors want to see a commercially supported WAF with logging and incident response capabilities. If you are processing credit cards, budget for at least Cloudflare Pro ($20/mo) or a managed ModSecurity provider.
ModSecurity vs Coraza: which free WAF should I choose?
ModSecurity if you are running Apache (it is built-in via mod_security2) or have an existing NGINX + ModSecurity setup that works. Do not fix what is not broken.
Coraza if you are starting fresh, deploying in containers/Kubernetes, or want better performance. Coraza is written in Go, has native integration with Envoy and Istio, and is where active development is happening. Both run the same OWASP CRS rules, so detection capability is identical.
ModSecurity's future is uncertain since Trustwave handed off maintenance. Coraza's community is growing. For new deployments in 2026, Coraza is the safer long-term bet.
What is NAXSI and why is it different from other free WAFs?
NAXSI (NGINX Anti XSS & SQL Injection) uses a positive security model. Instead of maintaining a database of known attack patterns (like CRS does), NAXSI defines what normal traffic looks like and blocks everything else. This means it catches novel attacks that pattern-based WAFs miss, but it requires more initial tuning to avoid blocking legitimate requests.
Created by Thibault Koechlin and maintained as a focused, founder-led open source project since 2011. NAXSI is specifically built for NGINX. It does not try to support Apache or run as a standalone proxy. That narrow focus keeps it lean and fast. If you run NGINX and want a WAF that does not depend on signature updates, NAXSI is worth evaluating.
How do free WordPress WAFs compare to server-level WAFs?
They protect at different layers. A server-level WAF (ModSecurity, NAXSI) filters requests before they reach PHP and WordPress. A WordPress plugin WAF (Wordfence, NinjaFirewall, BBQ) runs inside PHP and has access to WordPress context like user sessions and plugin states.
Server-level WAFs are faster (less overhead per request) and protect everything on the server, not just WordPress. WordPress plugin WAFs are easier to install (no server access needed) and can make smarter decisions using application context.
The ideal setup is both: a server-level WAF for broad protection and a WordPress plugin for application-aware rules. But if you can only pick one, a WordPress plugin WAF is usually more practical for site owners who do not manage their own servers.
Is Cloudflare free tier enough or do I need to self-host?
For most personal sites, blogs, and small business sites: Cloudflare free is enough. You get WAF rules, DDoS protection, SSL, and CDN at zero cost. The managed rules cover OWASP Top 10 attacks.
Self-host when you need: custom WAF rules (Cloudflare free does not allow them), full control over what gets blocked, the ability to inspect and modify rules, or when your organization cannot route traffic through a third-party network. Self-hosted WAFs also make sense when you are already running NGINX or Apache and adding ModSecurity/NAXSI is just a module enable away.
Final Thoughts
For any web application (not WordPress-specific)
If you have server access, ModSecurity with OWASP CRS is the proven choice. It has been protecting production sites for over a decade and the CRS community actively maintains rules against current threats. Starting fresh? Coraza runs the same rules with better performance and modern tooling.
If you want something opinionated that just works out of the box, BunkerWeb wraps everything into a Docker image with a web UI. For NGINX purists who want minimal overhead, NAXSI takes a unique positive-security approach that founder Thibault Koechlin has refined since 2011.
No server access? Cloudflare free tier gives you WAF + DDoS + CDN by changing your DNS records. The free WAF rules cover OWASP Top 10 attacks and managed rulesets. For most personal sites and small businesses, it is enough.
For WordPress specifically
Wordfence free gives you the deepest WordPress-aware protection with a 30-day rule delay. NinjaFirewall free gives you real-time rules with a lighter footprint. BBQ Firewall gives you the absolute lightest touch: under 10KB, zero config, a founder-led project where Jeff Starr has been refining the same ruleset for 15 years.
For the full WordPress WAF comparison, see our dedicated best WAF for WordPress guide.