NAXSI vs Solid Security (formerly iThemes Security)
Both NAXSI and Solid Security (formerly iThemes Security) are capable WAF solutions. The right choice depends on your specific infrastructure, budget, and feature requirements.
Overview
NAXSI and Solid Security (formerly iThemes Security) are both popular web application firewall solutions. This comparison will help you understand the key differences and choose the right one for your needs.
A lightweight, open source WAF module for NGINX that uses a scoring-based approach instead of signature matching, blocking attacks by detecting suspicious patterns rather than maintaining a vulnerability database.
Comprehensive WordPress security plugin with Patchstack-powered firewall rules, virtual patching, two-factor authentication, and site scanning for proactive protection.
Quick Comparison
| Feature | NAXSI | Solid Security (formerly iThemes Security) |
|---|---|---|
| Overall Rating | 3.4/5 | 4.1/5 |
| Free Tier | Yes | Yes |
| Pricing Model | Free (Open Source, GPLv3) | Freemium (Free tier + annual Pro license) |
| Ease of Use | 2.8/5 | 4.3/5 |
| Value for Money | 4.5/5 | 4.2/5 |
| Support | 2.5/5 | 4.0/5 |
| Open Source | Yes | Yes |
| Platforms | NGINX, Linux (Debian, Ubuntu, CentOS), FreeBSD, OpenBSD, NetBSD, Docker | WordPress (self-hosted) |
| Compliance | N/A (supports OWASP Top 10 protection patterns) | Contact vendor |
Pricing Comparison
Solid Security (formerly iThemes Security)
Model: Freemium (Free tier + annual Pro license)
Free Tier AvailableFree
$0
Pro (1 site)
$99/year (~$8.25/month)
Pro (multi-site)
From $199/year
Features Comparison
NAXSI
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Scoring-Based Detection
Assigns scores to suspicious patterns in requests. Blocks when the cumulative score exceeds a threshold, rather than relying on exact signature matches.
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Learning Mode
Monitors traffic and automatically generates whitelist rules for legitimate application behavior, reducing manual tuning effort during initial deployment.
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Virtual Patching
Apply custom rules to block specific vulnerabilities without modifying application code. Rules target raw requests or specific fields like headers, args, and body.
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Deny-by-Default
Operates like a DROP firewall. Common attack characters and patterns are blocked unless explicitly whitelisted for the target application.
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Lightweight Footprint
Written in C with only libpcre as a dependency. Adds minimal overhead to NGINX request processing.
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Dynamic Module Support
Can be compiled as a dynamic NGINX module, allowing it to be loaded without recompiling NGINX from source.
Solid Security (formerly iThemes Security)
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Patchstack Firewall
Virtual patching rules powered by Patchstack that protect against known plugin and theme vulnerabilities automatically.
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Two-Factor Authentication
Multiple 2FA methods including authenticator apps, email codes, and backup codes for all user roles.
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Passwordless Login
Login via passkeys and biometrics, eliminating password-based attacks entirely (Pro feature).
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Site Scanner
Checks for known malware, vulnerabilities in plugins and themes, and blocklist status.
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File Change Detection
Monitors WordPress core files and alerts when unexpected changes are detected.
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Security Dashboard
Unified dashboard showing security status, recent events, and actionable recommendations.
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Trusted Devices
Recognizes trusted devices and restricts admin access from unknown devices (Pro feature).
Which One Is Right for You?
The best WAF depends on your specific requirements, infrastructure, and team expertise.
NAXSI
- You need: Teams already running NGINX who want lightweight inline WAF protection, budget-conscious deployments, applications with predictable request patterns, virtual patching use cases
- You want to start with a free tier
- You prefer open-source solutions
- You're using: NGINX, Linux (Debian, Ubuntu, CentOS), FreeBSD, OpenBSD, NetBSD, Docker
Solid Security (formerly iThemes Security)
- You need: WordPress agencies managing multiple sites, users wanting modern authentication features like passkeys, sites needing automatic virtual patching for plugin vulnerabilities
- You want to start with a free tier
- You prefer open-source solutions
- You're using: WordPress (self-hosted)
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
Which is better for startups: NAXSI or Solid Security (formerly iThemes Security)?
Both NAXSI and Solid Security (formerly iThemes Security) offer free tiers, making them accessible for startups. Solid Security (formerly iThemes Security) scores higher for ease of use (4.3/5), which is valuable for smaller teams. Consider your immediate security needs and growth plans when choosing.
Which has better support: NAXSI or Solid Security (formerly iThemes Security)?
Solid Security (formerly iThemes Security) has a higher support rating (4.0/5) compared to NAXSI (2.5/5). However, support quality can vary based on your plan tier - enterprise customers typically receive more responsive support from both providers. Consider evaluating support during a trial period.
Which is easier to implement: NAXSI or Solid Security (formerly iThemes Security)?
Solid Security (formerly iThemes Security) scores higher for ease of use (4.3/5) versus NAXSI (2.8/5). The actual implementation effort depends on your existing infrastructure and team expertise.
Which is more cost-effective: NAXSI or Solid Security (formerly iThemes Security)?
Both providers offer free tiers, making it easy to start without commitment. NAXSI scores higher for value (4.5/5). Total cost depends on your traffic volume, required features, and support level needs.
Which is better for WordPress: NAXSI or Solid Security (formerly iThemes Security)?
Solid Security (formerly iThemes Security) explicitly supports WordPress while NAXSI takes a more platform-agnostic approach. For WordPress-specific threats like plugin vulnerabilities and brute force attacks, look for providers with WordPress-specific rule sets.