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Web Application Firewall

Protect your web applications with cloud-scale, API-centric security that detects and blocks the full spectrum of application attacks and OWASP Top 10 risks, while tuning continuously for your environments.

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Web Application Firewall dashboard showing total traffic at 540K, total threat traffic at 126K, blocked threat traffic at 97K, monitored threat traffic at 65K, and a traffic distribution line chart over time.

Full OWASP Top 10 Coverage

Harness WAF covers all of the OWASP Top 10 risks and can extend into API security and AI security when you are ready.

Deploy with Flexibility

Minimize DevOps friction deploying at edge, or use Harness as internal protection for advanced threats. The choice is yours, based on your architecture.

Protect APIs and Apps

Harness WAF inspects all application and API traffic, not just legacy technology. Modernize your WAF deployment for real-world designs.

Chart showing top OWASP 2021 threats by events with a total of 520 events; OWASP A1 at 178 and OWASP A3 at 94. Line graph displays top threat types distribution by events over time for Remote Code Execution and Cross Site Scripting from Oct 23 to Nov 2. Table lists top threat sources by country with United States leading at 216 events, followed by Netherlands at 156, Denmark at 12, and Germany at 9.

Stronger Web Application Protection

Cover All OWASP Top 10 Risks

Harness WAF with Harness API security features cover all of the OWASP Top 10 and OWASP API Security Top 10 risks in one platform.

Reduce Detection False Positives

Reduce false positive rates common in other WAFs that can't analyze exploitability of API interactions, like injection flaws. Harness WAF is built for APIs, the language of modern design.

API-First WAF For Improved Defense

Defend against traditional web application exploit patterns, and augment further with API context like request frequency, call sequences, and data flows.

Dashboard showing threat activities filtered by high confidence and Web Application Firewall category, listing API Protection and Web Application Firewall with severity, counts, confidence levels, and specific threat rules such as User-Agent scanner detection and path traversal attacks.

Deploy in Any Architecture

Edge-delivered Protection

Harness WAF protects at edge, can complement your existing CDN deployment with improved context, and position you for API-centic and AI-native designs.

Harden Cloud Deployments

Harness WAF operates in all the places you're used to with cloud provider offerings, adding stronger app protection combined with API context.

Protect Microservice Traffic

Harness WAF is engineered for east/west and inner service traffic, not just north/south traffic like other WAFs. Harness works with microservices, ingress controllers, and API gateways.

Reduce DevOps Friction

Application teams sometimes move faster than security, leading to fragmented WAF implementations. Harness WAF also operates as a DevOps-friendly option with enterprise-grade security.

Dashboard interface showing Security Events with filters, visualization bar chart of events over time, and a detailed table listing threat behaviors, severity, actor IPs, endpoints, services, times, event status, and event IDs.

Streamline Maintenance & Operations

Tune Quickly & Effectively

Legacy WAFs rely on static signatures and manually configured policies that overwhelm security teams. Harness WAF provides leading detection accuracy based on app and API signals.

Extended Signal Retention

Harness provides industry-leading data retention of application calls and critical security events to aid in your digital forensics and incident response (DFIR) processes.

Action on Full Telemetry

Harness captures full application requests and responses where other WAFs truncate. Improve signal fidelity so your SOC is triaging critical events, not wasting time hunting for data.

Abstract dark blue and green gradient background with subtle light in the center.

Security for Everything in Runtime

The Harness platform informs with API context, identifies sensitive data flows, protects against application-layer attacks, and guides on the best mix of protective controls to stop application abuse.

Illustration of a software security workflow from code to deployment including SAST, SCA, Container Security, API Testing, API Discovery, API Protection, Bot & Abuse Protection, and Web Application Protection stages.

API Testing

Find and eliminate API vulnerabilities with continuous scanning and contextualized remediation, without slowing development or release.

API Protection

Protect your APIs with advanced, unified security and defend against evolving threats across hybrid- and multi-cloud environments.

Bot & Abuse Protection

Mitigate bot attacks and API abuses that result in transaction fraud, data exposure, and business logic manipulation.

Related Resources

Summit

DevSecOps Summit 2025: Securing Applications From Within

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On-demand Webinar

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Frequently Asked Questions

What is a Web Application Firewall (WAF)?

A web application firewall (WAF) is a network-based security control that filters, monitors, and blocks malicious HTTP/HTTPS traffic to protect web applications from common attacks like SQL injection (SQLi), command injection, cross-site scripting (XSS), cross-site request forgery, and server-side request forgery (SSRF). Regulations and security standards, such as PCI DSS, often require protection for public-facing web applications. WAF can be used as an effective security control to achieve compliance depending on the organization's environments and scopes.

How does a WAF work?

A WAF inspects inbound and outbound layer 7 application/web traffic that typically runs over the HTTP/HTTPS protocol. WAFs apply security rules, or policies, and threat detection to identify malicious requests and well-known attack patterns. They can also block web application attacks to protect web applications in real time. Some organizations opt to deploy WAFs in detect-only, alerting, or monitoring mode so they don't inadvertently impact legitimate production usage. However, this is frequently a byproduct of inadequate tuning, false positive rates, or WAF efficacy concerns.

What’s the difference between a WAF and a traditional network firewall?

Traditional firewalls and next-generation firewalls (NGFW) focus on ports, IP addresses, and multiple network protocols. These foundational security controls are useful for protecting all types of network traffic, but they also broad spectrum protection which translates to less efficacy on HTTP/HTTPS specifically. Rules may be too generalized and only address basic web application attack patterns. A WAF focuses specifically on application-layer (L7) threats, protecting web applications from all types of application threats and OWASP Top 10 risks.

Does a WAF protect APIs as well as web applications?

Strictly speaking, APIs typically communicate over the same HTTP/HTTPS protocol as web applications, inheriting a base level of protection. However, not all WAFs are engineered to understand API context like gRPC, GraphQL, and REST. Many modern WAF solutions include API-specific protections as part of a broader WAAP (Web Application and API Protection) platform, helping detect API abuse, API schema violations, and authorization attacks on API endpoints.

What is WAAP and how is it related to WAF?

Web Application and API Protection (WAAP) platforms typically combine WAF, API discovery, API testing, API protection, bot & abuse protection, and denial-of-service (DoS) mitigation into a unified application runtime security platform that can detect and stop all types of application-layer (L7) attacks.

Is cloud WAF better than appliance WAF?

Cloud WAF is often easier to deploy and scale for modern system designs, delivered as SaaS or attached to a content delivery network (CDN). Appliance or on-premises WAF are often used to satisfy strict data residency requirements or where legacy technology stacks inhibit the use of cloud compute. The "best" WAF choice can be subjective based on organizational needs but often depends on numerous factors like availability thresholds, latency tolerances, regulatory mandates, and operational requirements. Some organizations, particularly ones in heavily regulated industries, employ both.

What is the OWASP Top 10, and does it matter for WAF?

The OWASP Top 10 is a widely used list of common web application security risks. A WAF helps reduce exposure to many of the risks by blocking exploit patterns and enforcing application-layer security controls. However, full coverage of the OWASP Top 10 and the adjacent OWASP API Security Top 10 risks requires a WAAP platform.

Where should WAF be deployed?

A WAF can run at the edge via SaaS-delivery or CDN, in-line as a reverse proxy or integration with other proxies like API gateways, or within microservice environments like Kubernetes. Even in the case of Kubernetes, WAF may attach to an ingress controller or operate as a sidecar container. The "best" placement balances security coverage, latency, and operations. WAFs are likely to be deployed at multiple points of infrastructure. A common pattern is to deploy WAF at edge for broad coverage with universal protection policies, and then deploy inner WAF if there is a desire for greater control over inner service calls or need for granular policies.

Does a WAF impact website performance or introduce latency?

A properly tuned WAF adds minimal latency, and the security benefits greatly outweigh any potential availability impacts. WAF deployed at the edge as a cloud service or with CDN is highly scalable and can actually improve application performance by absorbing attacks, caching content, and reducing load on origin web and application servers.

What are WAF rules?

WAF rules or policies define what traffic to allow, challenge, or block. Rules consist of expected behaviors, schemas, and parameters (in the case of positive security approaches) or known-malicious attack patterns (in the case of negative security approaches). Many WAF configurations use a mix of positive and negative rules. Managed rulesets are prebuilt, regularly updated security rules that protect against known exploits, OWASP Top 10 attack patterns, and emerging threats. The OWASP Core Rule Set (CRS) is often the foundation of such managed rulesets.

Web Application & API Protection