HTTP DDoS Attacks on API-Based Applications: A Growing Threat


The Rise of API Traffic

In today's digital landscape, most application traffic is API-based. Whether it's incoming traffic to your applications or outgoing traffic to third-party services, APIs are the backbone of modern web interactions. From booking flights to using ride-sharing apps and making payments, APIs facilitate seamless data flow.

Many applications today are API-based, including mobile apps, B2B and B2C platforms, and C2C services. Additionally, many web applications are actually hybrids, where the main host is an HTML webpage, but much of the functionality depends on API paths. There are four main types of application architectures today:

  1. Pure web applications (less common today)
  2. Pure API-based applications
  3. Mobile applications
  4. Web & API hybrid applications, which make up 80% of today's applications

Why Is API Traffic Dominant?

API traffic dominates due to several factors. APIs allow developers to separate backend and frontend functions, improving user experiences. The rise of microservices and serverless architectures has further increased their use. Additionally, APIs enable companies to scale, integrate services, and monetize new capabilities.

The Difficulty in Mitigating Web DDoS Attacks

Radware's 2025 Global Threat Analysis Report highlighted a 550% rise in web DDoS attacks in 2024. Most traditional solutions, such as rate limiting and geo-blocking, are not built to effectively mitigate aggressive HTTP DDoS attacks. These methods often cause high false-positive rates, blocking significant portions of legitimate traffic. JWT validation is also ineffective during aggressive HTTP floods, as servers buckle under the burden of parsing thousands of requests per second.

Many modern solutions rely on JavaScript validation, which has proven somewhat effective for mitigating HTTP floods targeting web-based applications. Some still use CAPTCHA, but its effectiveness has declined as attack tools increasingly bypass it. However, for API-based applications—the majority of today’s apps—both methods are entirely ineffective. Since APIs lack a browser interface, JS validation or CAPTCHA challenges sent to a browser go unanswered. As a result, legitimate API traffic is blocked along with attack traffic, rendering the application unavailable to real users.

Radware’s Unique Solution for HTTP DDoS Attacks on API-Based Apps

Radware provides a unique solution for mitigating web (Layer 7) DDoS attacks through its Cloud DDoS Protection and Cloud Application Protection Service.

Radware's multi-patented Web DDoS Protection solution learns an application's legitimate traffic behavior and uses proprietary AI-based algorithms to generate highly granular, real-time signatures—regardless of attack type. This approach is completely agnostic to whether the application is web- or API-based. Radware automatically mitigates HTTP flood attacks on the spot without relying on challenges, ensuring that legitimate users are not blocked.

Securing API-Based Applications Against Evolving Threats

HTTP DDoS attacks are a growing concern in today’s API-driven world. Understanding these attacks and implementing robust security measures is critical to protecting applications and data. Radware’s Web DDoS Protection solution offers real-time detection and automated mitigation, helping organizations safeguard their API-based applications against sophisticated threats while ensuring seamless digital interactions.

Uri Dorot

Uri Dorot

Uri Dorot is a senior product marketing manager at Radware, specializing in application protection solutions, service and trends. With a deep understanding of the cyber threat landscape, Uri helps companies bridge the gap between complex cybersecurity concepts and real-world outcomes.

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