Web Application Firewall (WAF)
A Web Application Firewall (WAF) is a security layer that inspects HTTP requests and blocks malicious traffic such as SQL injection, cross-site scripting, and known exploit patterns. It sits in front of web applications and APIs, filtering attacks before they reach origin servers.
Technical Architecture & Deep-Dive
WAFs apply managed rule sets, such as the OWASP Core Rule Set, plus custom rules based on paths, headers, IP reputation, and request rates. Edge-hosted WAFs evaluate every request at the nearest point of presence, stopping attacks far from your infrastructure.
For APIs, WAF rules can enforce allowed methods, block oversized bodies, and detect credential stuffing, complementing gateway authentication and rate limiting.
Key Architectural Benefits
Implement Web Application Firewall (WAF) at the Edge
Deploy lightweight API aggregation, edge caching, and secret injection in minutes without Docker containers or complex servers.
Frequently Asked Questions
Q:Does a WAF replace secure coding?
No. A WAF is a defense-in-depth layer. Applications must still validate input and enforce authorization correctly.
Related Architecture Concepts
DDoS protection defends services against distributed denial of service attacks, in which many compromised machines flood a target with traffic to make it unavailable. Protection systems detect and drop attack traffic while allowing legitimate requests through.
Bot protection is detecting and blocking automated traffic that abuses websites and APIs, such as scrapers, credential stuffing tools, and fake signup scripts, while allowing legitimate users and good bots like search crawlers. It combines fingerprinting, behavior analysis, and challenges.
API Rate Limiting is a traffic control mechanism that caps the number of requests a client, IP address, or API token can execute within a specified time window. Rate limiting prevents server overloading, protects against credential brute-forcing, and shields upstream APIs from exceeding subscription quotas.