Web Application Firewalls (WAF) can monitor, filter, and block suspicious or unwanted HTTP traffic to and from a web service or application. It specifically analyzes traffic between the internet and the web application. Using the OSI model, WAF solutions will deliver protection at the application layer (also called layer 7). While proxy servers can protect a user’s endpoint identity through using an intermediary, WAF operate differently. They act as a reverse-proxy by protecting the server from exposure and requiring users to navigate the WAF before accessing a server or application.
Web application firewalls are important to environments with multiple web applications and many users trying to access those applications regularly. WAFs provide adaptive and comprehensive protection for web applications and any company data that may be stored on those applications. Web application firewall solutions can be cloud-based, host-based, or network-based.
This article will identify the best web application firewalls on the market. Each listing will provide a summary of their capabilities and feature set to help you decide which solution meets your needs.
Radware Cloud WAF is a web application firewall that protects web apps and APIs across on-premises, cloud, and hybrid environments. Part of Radware’s Cloud Application Protection Service, it secures critical applications with a robust suite of threat mitigation tools.
Why We Picked Radware Cloud WAF: We picked Radware Cloud WAF for its AI-powered API protection and flexible deployment options, which guard against a wide range of threats while fitting diverse infrastructures.
Best Features: Radware Cloud WAF analyzes web apps to spot threats and auto-generates precise protection rules. It uses device fingerprinting to detect bot attacks and AI-driven API discovery to prevent abuse, covering OWASP Top 10 vulnerabilities. Data leak prevention blocks sensitive data transmission. Integrations with DAST tools enable real-time security patching for continuous deployment. Available as a cloud service, Kubernetes edition, or integrated with Radware’s ADC suite, it supports inline, out-of-band, and hybrid setups, with NSS recommendation and PCI-DSS compliance.
Strengths:
Spots and blocks threats with AI-driven rules
Protects APIs from abuse and manipulation
Stops data leaks to keep sensitive info safe
Works across cloud, on-prem, or Kubernetes
Connects with DAST for real-time patching
Pricing: Contact Radware’s sales team for pricing details. A free trial is available.
Who it’s for: Radware Cloud WAF fits organizations and development teams aiming to secure web apps and APIs against attacks like access violations, brute force, and advanced HTTP threats.
Akamai App & API Protector is a web application firewall that blends web app protection, bot mitigation, API security, and Layer 7 DDoS defense into a single solution. Akamai delivers high-performance security with extensive customization for diverse environments.
Why We Picked Akamai App & API Protector: We picked Akamai for its advanced API discovery and DevOps-friendly interface, which tackle complex threats while keeping management simple.
Best Features: Akamai App & API Protector uses an Adaptive Security Engine to spot vulnerabilities and block threats, covering OWASP Top 10 risks. Its AI-driven API discovery identifies unknown APIs to prevent abuse. The platform auto-updates security rules and provides real-time traffic and attack visibility through a clean dashboard. Layer 7 DDoS protection shields apps without slowing performance. DevOps integrations, guided setup wizards, and add-ons like managed services ease deployment and customization.
Strengths:
Catches unknown APIs with AI-driven discovery
Blocks threats fast with auto-updated rules
Shows clear traffic and attack data
Fits DevOps workflows with easy integrations
Handles large-scale DDoS without lag
Pricing: Contact Akamai’s team for pricing details.
Who it’s for: Akamai App & API Protector fits companies of all sizes needing a comprehensive platform to secure web apps and APIs against sophisticated attacks.
AWS WAF is a web application firewall that guards web apps and APIs against common threats like SQL injection, XSS, and bots through monitoring, filtering, and rate-limiting. Managed via AWS Firewall Manager, it offers centralized control and deep customization for AWS-hosted environments.
Why We Picked AWS WAF: We picked AWS WAF for its flexible rule builder and API-driven management, which let teams tailor security policies to fit specific needs.
Best Features: AWS WAF filters out attacks like SQL injection and XSS, blocking unwanted traffic by IP, behavior, or geolocation. Its visual rule builder and JSON-based options allow custom rules aligned with compliance needs. API integration automates rule creation and updates. Real-time metrics and raw request metadata (e.g., URLs, IP addresses) provide clear visibility into traffic and threats. Rate-limiting and bot control, powered by AWS Shield, mitigate DDoS and malicious bot activity.
Strengths:
Blocks common threats with precise filtering
Builds custom rules easily with visual or JSON tools
Automates security via API integrations
Shows real-time traffic and threat data
Scales seamlessly within AWS ecosystems
Pricing: Contact AWS’s team for pricing details.
Who it’s for: AWS WAF fits medium to large companies using AWS-hosted web apps and APIs, needing customizable, scalable protection against exploits and bots.
Barracuda Web Application Firewall, part of Barracuda’s Cloud Application Protection platform, shields web apps, APIs, and mobile app backends from OWASP Top 10 vulnerabilities and advanced web attacks. Based in California, Barracuda delivers flexible deployment and strong data loss prevention for robust security.
Why We Picked Barracuda Web Application Firewall: We picked Barracuda for its intuitive interface and auto-update feature, which keep protection current and easy to manage.
Best Features: Barracuda WAF inspects and filters traffic to block threats like SQL injection and XSS, while scanning outbound data to prevent leaks. It offers bot spam protection, volumetric and application DDoS defense, and adaptive profiling for precise threat detection. Auto-updates ensure defenses stay ahead of new risks. The platform supports granular policies, file upload controls, and strong authentication. Deployable as a physical or virtual appliance, cloud service, or managed service, it integrates with Barracuda’s email security and offers a full REST API.
Strengths:
Pricing: Contact Barracuda’s team for pricing details.
Who it’s for: Barracuda WAF suits organizations seeking robust web app and API protection, especially those also needing email security solutions.
Cloudflare WAF, part of Cloudflare’s cloud security suite, is a web application firewall that protects web apps and APIs with machine learning-driven threat detection and a global Content Delivery Network (CDN). Cloudflare combines DDoS mitigation and advanced rate limiting for robust defense.
Why We Picked Cloudflare WAF: We picked Cloudflare WAF for its no-code setup and real-time threat blocking, which make it quick to deploy and effective against emerging attacks.
Best Features: Cloudflare WAF uses machine learning to block threats like XSS, SQL injection, and remote code execution in real time, with layered rulesets including OWASP, managed, and custom rules. Its Managed Ruleset offers instant protection against zero-day vulnerabilities and data theft. Advanced rate limiting stops DDoS, brute-force, and API abuse. Real-time logging and raw log access provide clear visibility into threats. Deployable in minutes via a DNS change, it integrates with SIEM tools, WordPress, Drupal, and Cloudflare’s CDN, with FEDRAMP compliance.
Strengths:
Blocks new threats fast with machine learning
Sets up quickly with no-code tools
Stops DDoS and abuse with rate limiting
Shows detailed threat logs in real time
Integrates with popular platforms like WordPress
Pricing: Contact Cloudflare’s team for pricing details.
Who it’s for: Cloudflare WAF fits organizations needing an easy-to-manage, scalable solution to protect web apps and APIs from new and common threats.
F5 BIG-IP Advanced WAF is a web application firewall designed to guard web apps and APIs against sophisticated threats missed by other firewalls. It combines machine learning, threat intelligence, and app expertise to deliver strong protection across diverse environments.
Why We Picked F5 BIG-IP Advanced WAF: We picked F5 BIG-IP Advanced WAF for its machine learning-driven threat detection and broad API security, which tackle complex attacks effectively.
Best Features: F5 BIG-IP Advanced WAF blocks OWASP Top 10 threats and secures GraphQL, REST/JSON, XML, and GWT APIs. Machine learning powers accurate Layer 7 DDoS detection and proactive bot defense against automated attacks. App-layer encryption stops data-extracting malware and man-in-the-browser threats. Stolen credential protection adds an extra security layer. API-based deployment supports public/private cloud or on-premises setups, with integrations for DAST, SAST, SIEM, SOAR, and XDR tools, plus guided configurations for quick setup.
Strengths:
Stops complex threats with machine learning
Secures a wide range of API types
Blocks DDoS and bots with precise detection
Encrypts data to foil malware attacks
Connects easily with third-party security tools
Pricing: Contact F5’s team for pricing details.
Who it’s for: F5 BIG-IP Advanced WAF fits organizations seeking advanced protection for web apps and APIs against sophisticated threats like bots, DDoS, and data breaches.
Fastly Next-Gen WAF is a hybrid SaaS web application firewall that safeguards web apps, APIs, and microservices from advanced threats like account takeover, API abuse, and OWASP Top 10 vulnerabilities. It delivers real-time Layer 7 visibility and flexible protection across diverse environments.
Why We Picked Fastly Next-Gen WAF: We picked Fastly for its intuitive interface and versatile deployment options, which block sophisticated attacks while integrating smoothly with DevOps tools.
Best Features: Fastly Next-Gen WAF detects and blocks attacks on SOAP, REST, gRPC, WebSockets, and GraphQL APIs, using SmartParse to spot malicious payloads with high accuracy. It counters OWASP Top 10 threats, credential stuffing, and malicious bots via machine learning and rate limiting. Virtual patching and DDoS protection, including Layer 3/4 and Layer 7 defenses, are standard. The platform deploys in cloud, data center, hybrid, or containerized setups, with integrations for SIEM, DAST, and Kubernetes. Its clean dashboard offers instant access to reports and alerts for easy management.
Strengths:
Blocks API abuse with precise request inspection
Deploys fast across any environment
Stops bots and DDoS with advanced rate limiting
Shows clear, real-time threat data
Simplifies setup with out-of-the-box features
Pricing: Contact Fastly’s team for pricing details.
Who it’s for: Fastly Next-Gen WAF fits organizations of any size needing strong, flexible protection for web apps and APIs against advanced threats.
Fortinet FortiWeb is a web application firewall that protects web apps and APIs from OWASP Top 10 threats, DDoS attacks, and malicious bots. Backed by Fortinet’s machine learning-driven Cloud Threat Analytics, it delivers precise threat detection and actionable insights.
Why We Picked FortiWeb: We picked FortiWeb for its ML-based analytics and cross-referenced threat data, which spot new threats quickly and cut down false positives.
Best Features: FortiWeb blocks OWASP Top 10 vulnerabilities, DDoS attacks, and bots using FortiWeb Cloud Threat Analytics, which identifies attack patterns with machine learning. It scans security postures to suggest firewall configuration improvements, reducing false positives. Attack data is cross-referenced across Fortinet’s global customer base for enhanced threat detection. The platform prioritizes incident risks and integrates with workflows, offering threat-hunting playbooks. Deployable as a physical/virtual appliance, hosted, or cloud solution, it supports fast traffic encryption/decryption and protected WAF throughputs.
Strengths:
Spots threats fast with ML-driven analytics
Suggests fixes to tighten firewall settings
Uses global data to catch new attacks
Prioritizes risks with clear playbooks
Deploys flexibly across any environment
Pricing: Contact Fortinet’s team for pricing details.
Who it’s for: FortiWeb fits medium to large enterprises needing a powerful firewall to protect web apps and APIs from advanced threats.
Google Cloud Armor is a web application firewall that protects Google Cloud, hybrid, and multi-cloud deployments from threats like DDoS attacks, XSS, and SQL injection. It offers customizable security policies and advanced threat intelligence for robust application defense.
Why We Picked Google Cloud Armor: We picked Google Cloud Armor for its flexible rules language and Adaptive Protection, which block Layer 7 DDoS attacks while fitting diverse cloud setups.
Best Features: Google Cloud Armor provides preconfigured WAF rules and a robust rules language to create custom, prioritized security policies covering OWASP Top 10 threats. Adaptive Protection uses machine learning to detect and mitigate Layer 7 DDoS attacks in real time. It includes threat intelligence to identify malicious traffic patterns. The Enterprise edition adds always-on DDoS defense and extensive WAF rules. Deployable across Google Cloud, hybrid, or multi-cloud environments, it integrates with Cloud Load Balancing for easy setup and management.
Strengths:
Blocks DDoS and app threats with smart detection
Builds custom rules with a powerful language
Deploys easily across hybrid and multi-cloud
Uses preconfigured rules for quick protection
Shows real-time threat insights
Pricing: Contact Google Cloud’s team for pricing details.
Who it’s for: Google Cloud Armor fits organizations of all sizes using Google Cloud, hybrid, or multi-cloud setups, needing strong, customizable protection for web apps and APIs.
Imperva Cloud WAF is a cloud-based web application firewall that secures web apps, APIs, microservices, and cloud environments against OWASP Top 10 and advanced threats. Powered by Imperva Research Labs, it delivers fast, automated protection with minimal false positives.
Why We Picked Imperva Cloud WAF: We picked Imperva Cloud WAF for its flexible deployment options and real-time traffic profiling, which effectively block sophisticated attacks while maintaining ease of use.
Best Features: Imperva Cloud WAF blocks OWASP Top 10 attacks and uses behavioral analysis to detect threats like cross-site scripting, illegal resource access, and remote file inclusion. Its identification engine profiles traffic at the edge in real-time to distinguish legitimate from malicious requests. The platform supports multiple deployment models, including SaaS WAF, WAF gateway, cloud WAF, and physical or virtual appliances. An intuitive web interface, secured with two-factor authentication, simplifies management. A managed WAF option is available for organizations needing extra support.
Strengths:
Protects a wide range of applications and APIs
Identifies threats using real-time traffic analysis
Offers flexible deployment for any environment
Simplifies management with a user-friendly interface
Reduces false positives with research-driven detection
Pricing: Contact the Imperva team for pricing details.
Who it’s for: Imperva Cloud WAF is ideal for security teams, DevOps professionals, and organizations seeking robust, user-friendly protection for web applications, APIs, and cloud-based services across diverse environments.
NetScaler Web Application Firewall is a robust solution integrated into the NetScaler platform, protecting web applications, APIs, and services against OWASP Top 10, zero-day threats, and other advanced attacks. It combines multiple threat research sources to deliver fast, scalable security for cloud and on-premises environments.
Why We Picked NetScaler Web Application Firewall: We picked NetScaler Web Application Firewall for its hybrid security model and scalability, which effectively protect large-scale application environments while maintaining performance.
Best Features: NetScaler WAF uses pre-configured and customized signature rules for pattern matching to block malicious traffic. Positive security checks enforce admin-defined policies to defend against application-layer attacks. It offers signature protections for known vulnerabilities and distinguishes between good and bad bots to prevent spam and malicious requests. Automated security checks apply during application development and deployment. The platform supports both cloud and on-premises deployments for flexible integration.
Strengths:
Blocks a wide range of threats, including zero-day attacks
Scales to protect thousands of applications
Applies security checks during development and deployment
Filters malicious bots and spam effectively
Fits both cloud and on-premises environments
Pricing: Contact the NetScaler team for pricing details.
Who it’s for: NetScaler Web Application Firewall is ideal for security teams and large enterprises needing scalable, high-performance protection for hundreds or thousands of web applications and APIs across diverse environments.
Integrated WAF service protecting Azure apps from common threats.
Offers WAF capabilities integrated with network security and endpoint protection.
Cloud-native WAF offering advanced threat prevention and DDoS protection.
Integrated WAF with load balancing and application delivery capabilities.
Selecting the right Web Application Firewall (WAF) solution involves aligning the platform with your organization’s application ecosystem, security needs, and operational requirements. Consider these key steps to make an informed choice:
Assess Your Application Environment: Evaluate your web applications (e.g., on-premises, cloud, hybrid), APIs, and traffic volume to ensure the WAF supports your infrastructure and protects against relevant threats like OWASP Top 10 vulnerabilities.
Define Security and Compliance Goals: Identify critical threats (e.g., SQL injection, XSS, DDoS) and regulatory standards (e.g., GDPR, PCI DSS) to ensure robust protection, compliance reporting, and data breach prevention.
Prioritize Scalability and Performance: Choose a solution that handles current traffic and scales for growth, multi-cloud setups, or high-traffic events without compromising speed or user experience.
Focus on critical features to ensure comprehensive protection and manageability:
OWASP Top 10 and Zero-Day Protection: Look for WAFs with rule-based and AI-driven detection (e.g., Cloudflare’s ML-based rules, Imperva’s near-zero false positives) to block common and emerging threats like XSS, SQL injection, and API abuse.
Bot and DDoS Mitigation: Prioritize solutions with bot detection, rate limiting, and CAPTCHA challenges (e.g., Barracuda’s bot protection, AppTrana’s DDoS mitigation) to prevent automated attacks and volumetric floods.
API Security and Analytics: Ensure API discovery, positive security models, and real-time traffic monitoring (e.g., Fortinet FortiWeb’s analytics, Azure WAF’s Sentinel integration) to secure APIs and provide actionable insights.
Flexible Deployment Options: Verify support for cloud, on-premises, or hybrid deployments (e.g., Sucuri’s cloud WAF, Radware’s hybrid model) to match your infrastructure and minimize latency.
Balance functionality with usability to maximize adoption and efficiency:
User-Friendly Interface: Avoid complex platforms that burden teams, opting for intuitive dashboards and automated rule updates (e.g., Cloudflare’s quick setup, AppTrana’s managed services) to simplify management.
Vendor Support Quality: Select providers with 24/7 support, detailed documentation, and resources like training or forums (e.g., Imperva’s global SOC, Barracuda’s support) to assist with deployment and incident response.
Testing and Trials: Use demos, free trials (e.g., offered by Azure WAF or Sucuri), or independent user reviews to validate threat detection, performance, and fit before committing.
Our guide to the leading web application firewalls provides a comprehensive overview of platforms designed to protect web applications and APIs from sophisticated cyber threats like SQL injection, XSS, and DDoS attacks. The article evaluates tools based on features like OWASP Top 10 protection, bot and DDoS mitigation, API security, and flexible deployment options, catering to organizations of all sizes. It emphasizes balancing advanced security, scalability, and usability to safeguard applications, ensure compliance, and maintain performance in cloud, on-premises, or hybrid environments facing an evolving threat landscape.
Key Takeaways:
Comprehensive Threat Protection: Top WAFs use AI, machine learning, and rule-based defenses to block OWASP Top 10 vulnerabilities, zero-day threats, and API abuse in real time.
Scalable and Flexible: Choose solutions with cloud, on-premises, or hybrid deployments to secure diverse applications while maintaining low latency and high availability.
Managed and Automated: Prioritize platforms with automated updates, managed services, and intuitive interfaces to reduce false positives and administrative overhead.
We’ve explored the leading web application firewalls, highlighting how these tools protect applications and APIs with advanced threat detection, bot mitigation, and seamless integrations. Now, we’d love to hear your perspective—what’s your experience with WAF platforms? Are features like AI-driven detection, managed services, or API security critical for your organization’s web security strategy?
Selecting the right WAF can transform how you secure your digital assets, but challenges like false positives, deployment complexity, or performance impacts can arise. Have you found a standout platform that’s strengthened your defenses, or encountered hurdles with scalability or usability? Share your insights to help other organizations navigate the WAF landscape and choose the best tool for their needs.
Let us know which solution you recommend to help us improve our list!
A web application firewall (WAF) is a security tool that helps to protect web applications and safeguard data through analyzing, monitoring, and filtering all HTTP traffic between web applications and the internet. A WAF solution sits between the internet and your organization’s web server to scan all inbound traffic for threat identification and filtering.
Some web application firewalls are also able to scan outbound traffic to deliver data loss prevention capabilities and insider threat mitigation. Web application firewalls are effective at identifying, filtering, and preventing web-borne threats, such as SQL injections, cross-site forgery, and cross-site scripting, as well as other cyber attacks.
WAF solutions work as a sort of reverse-proxy; they protect a server from threats by ensuring that all traffic has passed through the firewall filter before being granted access to the server. A firewall acts as a semi-permeable Shield between the internet and the application; only safe traffic is allowed through.
Like with most firewalls, web application firewalls will block content based on a set of preconfigured rules and policies. Most firewall solutions allow you to specify and configure policies and rulesets for your organization, giving you control over what your firewall blocks. These policies should be robust and versatile enough to block new, zero day threats.
WAF solutions tend to use block and allowlists to quickly categorise traffic. Blocklist protect against known attacks and restrict access to unknown traffic. Allowlists only admit traffic from known, trusted users. This limits the number of sources that have access to your network, thereby decreasing the chances for your network to be compromised.
There are three main types of web application firewalls: cloud-, network-, and host-based WAF solutions.
Web application firewalls operate at layer 7 in a network–the application layer. But what does that mean?
The Open Systems Interconnection (OSI) model details the seven layers that computer systems use to communicate. Conceptually, it splits up communication into seven layers to better understand how endpoints interact with each other. Its main purpose is to provide people with a sense of how traffic flows around a network.
Caitlin Harris is the Deputy Head of Content at Expert Insights. As an experienced content writer and editor, Caitlin helps cybersecurity leaders to cut through the noise in the cybersecurity space with expert analysis and insightful recommendations. Prior to Expert Insights, Caitlin worked at QA Ltd, where she produced award-winning technical training materials, and she has also produced journalistic content over the course of her career. Caitlin has 8 years of experience in the cybersecurity and technology space, helping technical teams, CISOs, and security professionals find clarity on complex, mission critical topics like security awareness training, backup and recovery, and endpoint protection. Caitlin also hosts the Expert Insights Podcast and co-writes the weekly newsletter, Decrypted.
Laura Iannini is a Cybersecurity Analyst at Expert Insights. With deep cybersecurity knowledge and strong research skills, she leads Expert Insights’ product testing team, conducting thorough tests of product features and in-depth industry analysis to ensure that Expert Insights’ product reviews are definitive and insightful. Laura also carries out wider analysis of vendor landscapes and industry trends to inform Expert Insights’ enterprise cybersecurity buyers’ guides, covering topics such as security awareness training, cloud backup and recovery, email security, and network monitoring. Prior to working at Expert Insights, Laura worked as a Senior Information Security Engineer at Constant Edge, where she tested cybersecurity solutions, carried out product demos, and provided high-quality ongoing technical support. She holds a Bachelor’s degree in Cybersecurity from the University of West Florida.