10 Best Web Application Firewalls

Best Web Application Firewalls

Diego Asturias

A Web Application Firewall (WAF) is a security system that aims to protect web apps and sites, using a set of rules that filter HTTP traffic. It monitors and blocks any malicious or abnormal behaviors coming from the Internet and going towards web apps.

A Web Application Firewalls (WAF) software solution should be capable of dealing with OWASP’s top ten. Some of these common web attacks include: 

  • SQL injections.
  • Cross-site forgery.
  • DDoS attacks,
  • Cross-Site Scripting (XSS).
  • and other types of attacks.

Still, web apps are vulnerable to zero-day attacks or might have unique traffic patterns, so a WAF must look beyond the common web attacks.

More advanced WAF solutions can provide automated defenses and managed services to control these sets of rules. These advanced WAF solutions give access to expert security teams, edge networks, threat intelligence, AI/ML analytics, traffic monitoring, and more.

In this post, we’ll go through the best WAF vendors that provide the most comprehensive web app security:

  1. StackPath Web Application Firewall. A cloud-based WAF powered by a globally massive and automated edge network. It offers protection from L3/4/7 DDoS attacks, botnets, and more.
  2. Sucuri Website Firewall. A cloud-based WAF with a large database of attack signatures developed by Sucuri’s expert research.
  3. Imperva Cloud WAF. A component of an integrated defense suite, including CDN, DDoS mitigation, bot protection, and more.
  4. Barracuda Web Application Firewall. It uses positive signature-based rules and robust analysis/detection capabilities to defend your assets.
  5. AppTrana Managed Web Application Firewall A fully-managed WAF designed to automatically scan, find vulnerabilities, and patch applications. AppTrana is bundled with a CDN and managed security rules.
  6. AWS WAF. A cloud-based WAF that leverages other AWS services to detect and mitigate web attacks.
  7. F5 Advanced WAF. It uses a combination of threat intelligence and ML to protect web apps from data breaches, zero-day, and OWASP’s top ten risks.
  8. Cloudflare WAF. A cloud-based WAF that leverages a massive CDN, provides automatic protection from app’s vulnerabilities and allows customized rules.
  9. Akamai Kona Site Defender.  Built on Akamai Intelligent Edge Platform and designed to protect web apps, sites, and API from OWASP’s top ten, L7 DDoS, and zero-day attacks.
  10. Radware Cloud WAF. A cloud-based WAF capable of responding against the most sophisticated and damaging web threats.

The 10 Best Web Application Firewalls

1. StackPath Web Application Firewall

StackPath Web Application Firewall

SP// WAF is a cloud-based service that comes with built-in rules created by StackPath’s team of security experts. Right out-of-the-box, these rules include protection from OWASP’s top ten and can be further customized to match your needs. The StackPath's security experts, maintain these rules up to date and ensure that your WAF gets updated immediately.

More features?

  • Device-level fingerprinting.
  • Bot traffic protection
  • Layer 7 DDoS protection.
  • Advanced threat protection via behavioral WAF.

Unique Value?

StackPath is a leader in secure edge CDN platforms. SP// WAF stands out because it is powered by StackPath’s high-performance and automated global edge platform. Their 50 edge global locations synchronize threat detection to help mitigate sophisticated attacks and reduce false positives.

Price: WAF for “websites with standard traffic” starts at $10/month. Request a demo.


2. Sucuri Website Firewall

Sucuri Website Firewall

Sucuri’s WAF is a cloud-based web application firewall that improves the detection of OWASP’s top ten. It comes with its own set of rules, but also allows you full customization. The predefined rules are powered by Sucuri’s continuous research on threats and mitigation strategies.

More Features?

  • DDoS protection.
  • Prevent zero-day exploits.
  • CDN to reduce traffic load.
  • Automatic patching and system hardening

Unique Value?

When the Sucuri service is defending other websites, it updates and maintains a large database of attack signatures. Sucuri will apply the same mitigation strategy (rules) that help them solve another issue. Additionally, Sucuri’s WAF gives you access to their global CDN to mitigate DDoS attacks, speed up load time, or increase availability.

Price: Three licenses: Basic ($199.99/yr), Pro ($299.99/yr), and Business ($499.99/yr). Sign up to request a free consultation.


3. Imperva Cloud WAF

Imperva Cloud WAF

Imperva cloud-based WAF protects your websites and apps from the newest and most sophisticated web threats. It protects assets regardless of their location, either on-premise or in the cloud.

Imperva Research Labs is actively searching and discovering new threats including the OWASP Top 10 and beyond. Imperva’s security experts monitor new vulnerability landscapes from external sources and propagate updated WAF rules on a daily basis.


  • Optional managed service.
  • Anti-DDoS solution.
  • Global CDN.
  • Integration with AI-based Imperva Attack Analytics.

Unique Value?

The Imperva Cloud WAF is a key component of the integrated defense suite, Imperva Application Security. The WAF is empowered by other apps and services like CDN, DDoS protection, load balancing, and bot protection. These apps and services are found at every single edge server.

Price: Contact the Imperva team to get a quote and a free demo.

4. Barracuda Web Application Firewall

Barracuda Web Application Firewall

Barracuda is a leader in enterprise-grade, cloud-ready security solutions. They develop the Barracuda WAF to protect your web, mobile, API applications, and website from attacks. The WAF knows how to safeguard against the OWASP Top 10, plus zero-day risks, data leaks, and DDoS layer 7 attacks.

Barracuda WAF can be implemented in any size of business. It is available on appliances, as WAF-as-a-Service, for private cloud, and as a virtual machine.

Key Features.

  • Barracuda Active DDoS Prevention.
  • Identifies and blocks bots.
  • Control access and authentication.
  • Data leak prevention by monitoring traffic.

Unique Value?

Barracuda WAF combines positive signature-based rules with robust analysis and detection capabilities. So, it is capable of not only stopping known attacks but also zero-day vulnerabilities and data loss.

Price? Request a price or get a free Barracuda WAF evaluation.


5. AppTrana Managed Web Application Firewall

AppTrana Managed Web Application Firewall

AppTrana Managed WAF is developed by Indusface, a leader in web security apps. The WAF is backed up by a managed security service, that provides 24/7 security experts to help you develop vulnerability patching rules.

The AppTranna WAF is optimized out-of-the-box with a set of rules, developed by Indusface after thousands of website security assessments. Users can use these rules or create/customize as required.

AppTranna WAF provides: 

  • Automatic security scans.
  • Protection from DDoS.
  • A Content Delivery Network.

Unique value? AppTranna WAF is one of the only few web security tools that puts application’s protection first. It will automatically scan and identify the app’s vulnerabilities and install patches as necessary.

Price: Premium ($399/app/month) and Advanced ($99/app/month). Test AppTrana with a 14-day free trial.




AWS WAF is a cloud-based WAF that protects web apps and APIs from common web attacks that affect the availability or consume excessive resources.

The AWS WAF comes with a pre-configured ruleset, that allows you to start using the WAF, right out of the box. These rules can deal with the OWASP top 10 security risks. But you can also define your own security rules that filter specific traffic patterns.

You can deploy AWS WAF on and with other AWS services like: 

  • Amazon CloudFront (a powerful CDN).
  • Application Load Balancer
  • Amazon API Gateway for your REST APIs,
  • AWS AppSync for your GraphQL APIs.
  • AWS CloudWatch to monitor incoming traffic.
  • Amazon Kinesis Firehose to tune rules based on log data.

Unique Value?

AWS is a leader in public cloud computing, CDNs, and APIs. By itself, AWS WAF is not as powerful as other WAFs in the market, but when you combine it with other AWS services, the WAF can turn out as one of the best.

Price: AWS uses a pay-as-you-use model. You can get an estimate with the AWS price calculator.


7. F5 Advanced WAF

F5 Advanced WAF

F5 Advanced WAF is a comprehensive web app, site, and API protection against OWASP's top ten and other sophisticated attacks. It protects your assets with behavioral analytics, API inspection, proactive defense from malicious bots and automation attacks, and application-level data encryption.

F5 Advanced WAF is available as an appliance, as software (to deploy in a hypervisor, data center, or private cloud), as-a-Service, and via public clouds (AWS, Azure, and GPC).

Key Features.

  • Basic ADC features, including load balancing, SSL offloading, etc.
  • Layer 7 DDoS protection.
  • Proactive bot defense.
  • Datasafe to encrypt data and credentials.
  • API Security.
  • Anti mobile bot SDK

Unique Value?

The F5 Advanced WAF combines Machine Learning (ML), threat intelligence (F5 Threat Campaigns), and deep application expertise.

Price: Contact the F5 sales department to get a quote or try F5 Advanced WAF for free.


8. Cloudflare WAF

Cloudflare WAF

Cloudflare WAF is an intelligent and scalable solution. It protects web apps, sites, and APIs from common OWASP top ten, and sophisticated DDoS attacks.

The WAF comes with a dashboard where you can build and customize firewall rules and integrate it with the Terraform API. Every request made to your web assets is inspected against a defined set of rules and CloudFlare's threat intelligence. The Cloudflare WAF also integrates Machine Learning (ML) and signature-based heuristics for intelligent analysis.


  • API integration.
  • Threat intelligence obtained by evaluating 1B+ IPs.
  • Large CDN and Anycast network.
  • Protection from L7 DDoS attacks.

Unique Value?

Cloudflare is pretty popular for having one of the largest CDNs in the world. It comprises hundreds of data centers distributed across the globe, in +100 countries. This CDN is optimal for providing protection against volumetric attacks (DDoS) coming from botnets or automated scripts.

Price: There are four pricing plans: Free, Pro ($20/month), Business ($200/ month), and Enterprise.


9. Akamai Kona Site Defender

Akamai Kona Site Defender

Akamai Kona Site Defender is a highly scalable cloud-based WAF designed to safeguard web apps, APIs, and websites from common web vulnerabilities and sophisticated attacks like L7 DDOS.

Kona Site Defender uses a proprietary anomaly detection engine with input from security experts, researchers, and ML algorithms. The proprietary pre-configured rules are tested against live traffic to avoid false positives and negatives and efficiently block attacks.


  • Automatic API discovery and security.
  • CDN with +300,00 servers.
  • Granular attack visibility and reporting
  • Optional access to Akamai Threat Intelligence Team.

Unique Value?

Akami is a leader in CDN services and cloud security solutions. It focuses on delivering security at the edge, closer to where an attack originated and far away from your application servers. Akamai has unmatched visibility of the threat landscape. Its WAF rules are triggered 178 billion a day, which gives them an advantage on threat intelligence.

You can test Akamai’s Web Application Protector (a simplified DDoS and application-layer security) for free for 30 days.


10. Radware Cloud WAF

Radware Cloud WAF

The Radware Cloud WAF is an adaptive security solution that protects from OWASP's top 10, zero-day, and emerging threats. It detects new web applications and protects them using its automatic rule generation engine.

Radware provides a cloud services portal that unifies WAF and other solutions including DDoS protection and access to Radware’s Emergency Response Team.

Key Features:

  • Always-on WAF protection.
  • Zero-day protection.
  • Sophisticated Malware protection.
  • Optional fully managed service.

Unique Value?

Radware is a global leader in integrated application delivery solutions. It was ranked by Gartner as the top API and high-security use case in 2020. The company is known for solving the most sophisticated web threats, and DDoS, with its cloud WAF and DDoS protection solutions.

Price? Contact the Radware team to get a quote.


How to choose the right WAF?

Look for solutions that give you protection from OWASP's top ten.

Most of the solutions shown in this post will give you protection from OWASP's top ten and might even go beyond it. They accomplish “more,” by solving zero-day attacks and identifying abnormal traffic using AI and ML. Additionally, all the tools give you access to threat intelligence and security experts that help identify even the most sophisticated attacks.

If you don’t know which way to go, you can test the WAF waters for free with some services like AppTrana, F5 Advanced WAF, or Akamai.