Caido: The Modern, Rust-Powered Web Security Toolkit Redefining Penetration Testing

By N0aziXss | Security Researcher | HackerOne & BugCrowd Validated

Introduction: A New Era for Web Security Testing

For years, Burp Suite has been the industry standard for web application security testing. However, the landscape is shifting. Enter Caido — a modern web security auditing toolkit built from the ground up in Rust. Designed by a team of three, with an advisory board including prominent security experts Caido is rapidly establishing itself as a leading choice for penetration testers, bug bounty hunters, and security professionals alike.

We started Caido to give hackers a tool that feels modern, reliable, and thoughtfully designed — something we'd want to use every day and one that's approachable even if you're a beginner.

— Ian Bouchard, Caido Cofounder

Why Caido? The Core Philosophy

Caido was created to address the pain points security professionals face with traditional tools. While Burp Suite offers a comprehensive

feature set, its complexity can be overwhelming and its resource efficiency often struggles. Caido takes a different approach:

· Performance: Built in Rust, it delivers a fast, seamless experience with low memory usage and unparalleled performance. · Simplicity: Focuses on a clean, intuitive interface that simplifies workflows without sacrificing power. · Modern Development: Plugins are written in HTML, CSS, and JavaScript — languages web hackers already know — eliminating the need to learn Java.

Core Features: Classic Meets Cutting-Edge

Caido combines the essential tools you rely on with modern enhancements. Its core features include:

🔍 Traffic Interception & History Intercept and monitor all HTTP and WebSocket traffic with powerful proxy capabilities. A complete history of all intercepted traffic and WebSocket messages is maintained for easy reference.

🚀 Automate & Replay · Automate: Run automated attacks with custom payloads, placeholders, and batch testing for comprehensive security assessments. · Replay: Manually test and modify requests, with the ability to replay, edit, and iterate for thorough analysis.

🗺️ Sitemap & Scope · Sitemap: Visual mapping of discovered endpoints and application structure. · Scope & Filters: Define target scope and apply powerful filters to focus testing on specific domains, paths, or request types.

⚡ Match & Replace Automatically modify requests and responses on-the-fly with powerful match and replace rules for dynamic traffic manipulation.

📋 Findings An issue tracking system where you, workflows, and plugins can create entries for interesting requests and potential vulnerabilities.

Plugin Ecosystem: Extend and Empower

Caido's true power lies in its growing ecosystem. With 42 plugins now available (29 added in 2025 alone) from a community of developers, you can enhance your workflow with custom tools and integrations.

Plugin Description

Scanner Automatically detect vulnerabilities with Caido's official, template-based detection engine. ParamFinder Discover hidden parameters in request queries, bodies, and headers. JWT Analyzer Detect and assess JSON Web Tokens for security issues. Autorize Automatically identify authorization/access control vulnerabilities. GraphQL Analyzer Schema discovery, visualization, and advanced security testing for GraphQL. CSP Auditor Hunts for CSP misconfigurations and cracks headers wide open.

Built-in Project Management

Caido includes a robust project management system that keeps penetration testing work organized and efficient. Each assessment gets its own dedicated workspace, allowing you to: · Organize by Assessment: Create separate projects for each penetration test. Keep traffic, findings, and notes organized by client or target. · Seamless Switching: Switch between different penetration tests instantly. · Maintain Context: Each project maintains its own traffic history, findings, and configuration.

Caido vs. Burp Suite: A Quick Comparison

Caido positions itself as a modern alternative to Burp Suite. Here's how they compare:

Feature Caido Burp Suite Pricing Free $200/y (Professional) Unlimited Installations ✅ ❌ Project Management ✅ ❌ Unrestricted Automation ✅ ❌ (Rate-limited Intruder) Intuitive Filtering ✅ HTTPQL ❌ Bambdas No-Code Customizations ✅ ❌ Simplified Plugin Development ✅ (HTML/CSS/JS) ❌ (Java) Remote Hosting ✅ ❌

Key Advantages of Caido:

· HTTPQL: A powerful yet easy-to-use query language for searching and filtering requests — no coding skills required. · Workflows: Create powerful automations through an intuitive, visual interface. No coding knowledge required. · Modern Architecture: Client-server architecture gives you complete control over sensitive findings, traffic history, and project data.

I use Caido for almost all my manual testing because the UI is cleaner, workflows are clutch, sorting and filtering are way better, and HTTPQL is king.

— Tadi K., Security Professional

Recent Milestones: The 2025 Evolution

2025 was a transformative year for Caido, with 10 major releases

addressing 277 features and bug fixes. Key highlights include:

🌐 WebSocket Interception (v0.48.0) Intercept and edit WebSocket messages directly from the Intercept page, just like with HTTP requests.

👤 Guest Mode (v0.48.0) Use Caido without an account. Guest sessions are limited to temporary projects.

🔄 Invisible Proxying Support (v0.47.0) Intercept traffic from non-proxy-aware clients without manual proxy configuration.

🌍 DNS Override (v0.47.0) Set specific IP addresses or DNS servers to resolve domain names as needed.

🔧 Match & Replace Redesign (v0.47.0) Completely redesigned to be more powerful and intuitive, with workflow support for dynamic replacements.

📊 HTTPQL for Intercept Filter out the noise to find specific requests and responses.

Kali Linux 2025.3 Integration

A significant milestone for Caido was its inclusion in Kali Linux 2025.3. With just a single command, you can now install Caido as a desktop app or via CLI, making it even more accessible for penetration testers and bug bounty hunters. This inclusion in the world's most popular penetration testing distribution cements Caido's status as a essential tool in the modern security professional's arsenal.

Getting Started with Caido

Installation

Download Caido from caido.io and install the desktop app for your operating system.
On Kali Linux 2025.3+: sudo apt install caido caido-cli.

Basic Setup

Open Caido and click New Instance.
Give it a name (e.g., "Target Assessment").
Configure your browser to use Caido as a proxy.
Start intercepting traffic and testing.

Conclusion: The Future of Web Security Testing

Caido represents a paradigm shift in web security testing tools. By combining Rust's performance, a modern, intuitive interface, a vibrant plugin ecosystem, and no-code automation through Workflows, it addresses the pain points that have long frustrated security professionals.

Whether you're a seasoned penetration tester, a bug bounty hunter, or just getting started in web application security, Caido offers a compelling alternative to traditional tools. With over 36,000 new users in 2025 alone and official inclusion in Kali Linux, Caido is not just a trend — it's the future of web security testing.

Caido becomes a proxy server, giving you the ability to view, intercept, and modify HTTP requests and responses to conduct web application security testing.

— Bugcrowd Beginner's Guide

Call to Action:

Developers: Implement strict input validation Researchers: Always redact sensitive information in reports Organizations: Value ethical security research

About the Author

N0aziXss is an experienced security researcher specializing in web application security and bug bounty hunting, with multiple validated discoveries across various platforms.