Compare the Top Free Debugging Tools as of April 2025

What are Free Debugging Tools?

Debugging tools, also known as debuggers, are software tools that enable web developers and software developers to debug their code and applications in order to improve the quality and security of the code and application. Compare and read user reviews of the best Free Debugging tools currently available using the table below. This list is updated regularly.

  • 1
    Fiddler

    Fiddler

    Progress Software

    Capture all HTTP(S) traffic between your computer and the Internet with Telerik Fiddler HTTP(S) proxy. Inspect traffic, set breakpoints, and fiddle with requests & responses. Fiddler Everywhere is a web debugging proxy for macOS, Windows, and Linux. Capture, inspect, monitor all HTTP(S) traffic between your computer and the Internet, mock requests, and diagnose network issues. Fiddler Everywhere can be used for any browser, application, process. Debug traffic from macOS, Windows, or Linux systems and iOS or Android mobile devices. Ensure the proper cookies, headers, and cache directives are transferred between the client and server. Supports any framework, including .NET, Java, Ruby, etc. Mock or modify requests and responses on any website. It’s a quick and easy way to change the request and responses to test websites without changing code. Use Fiddler Everywhere to log all HTTP/S traffic between your computer and the Internet.
    Starting Price: $12 per user per month
  • 2
    HTTP Toolkit

    HTTP Toolkit

    HTTP Toolkit

    Skim through traffic with highlighting by content type, status & source, or use powerful filtering tools to precisely match the messages that matter to you. Examine the URL, status, headers & body of each request or response, with inline explanations & docs from MDN. Dig into message bodies with highlighting & auto formatting for JSON, HTML, JS, hex and others, all using the power of Monaco, the editor from Visual Studio Code. Precisely match requests, jump to them when they appear, and edit anything: the target URL, method, headers or body. Manually respond directly to requests as they arrive, or pass them upstream, and pause & edit the real response on the way back. Step through HTTP traffic request by request, or manually mock endpoints and errors. Create rules to match requests and respond with your own content, to quickly prototype against new endpoints or services.
    Starting Price: Free
  • 3
    Ambassador

    Ambassador

    Ambassador Labs

    Ambassador Edge Stack is a Kubernetes-native API Gateway that delivers the scalability, security, and simplicity for some of the world's largest Kubernetes installations. Edge Stack makes securing microservices easy with a comprehensive set of security functionality, including automatic TLS, authentication, rate limiting, WAF integration, and fine-grained access control. The API Gateway contains a modern Kubernetes ingress controller that supports a broad range of protocols including gRPC and gRPC-Web, supports TLS termination, and provides traffic management controls for resource availability. Why use Ambassador Edge Stack API Gateway? - Accelerate Scalability: Manage high traffic volumes and distribute incoming requests across multiple backend services, ensuring reliable application performance. - Enhanced Security: Protect your APIs from unauthorized access and malicious attacks with robust security features. - Improve Productivity & Developer Experience
  • 4
    PlatformIO

    PlatformIO

    PlatformIO

    Professional collaborative platform for embedded development. PlatformIO is a next-generation, collaborative platform for embedded development that enables customers to save resources and time by vastly reducing the expenses and labor associated with creating and maintaining product software. We believe the embedded systems industry desperately needs reinvention. Not only are the IDEs and tools built with technology from the 1990s, but they involve many complex requirements and platform-dependent configurations that turn away talented developers from becoming embedded engineers. The most loved IDE solution for Microsoft Visual Studio Code. A user-friendly and extensible integrated development environment with a set of professional development instruments, providing modern and powerful features to speed up yet simplify the creation and delivery of embedded products. PlatformIO is written in pure Python and doesn't depend on any additional libraries/tools from an operation system.
  • 5
    Telepresence

    Telepresence

    Ambassador Labs

    Telepresence streamlines your local development process, enabling immediate feedback. You can launch your local environment on your laptop, equipped with your preferred tools, while Telepresence seamlessly connects them to the microservices and test databases they rely on. It simplifies and expedites collaborative development, debugging, and testing within Kubernetes environments by establishing a seamless connection between your local machine and shared remote Kubernetes clusters. Why Telepresence: Faster feedback loops: Spend less time building, containerizing, and deploying code. Get immediate feedback on code changes by running your service in the cloud from your local machine. Shift testing left: Create a remote-to-local debugging experience. Catch bugs pre-production without the configuration headache of remote debugging. Deliver better, faster user experience: Get new features and applications into the hands of users faster and more frequently.
    Starting Price: Free
  • 6
    Xdebug

    Xdebug

    Xdebug

    Xdebug is an extension for PHP, and provides a range of features to improve the PHP development experience. A way to step through your code in your IDE or editor while the script is executing. An improved var_dump() function, stack traces for notices, warnings, errors, and exceptions to highlight the code path to the error. Writes every function call, with arguments and invocation location to disk. Optionally also includes every variable assignment and return value for each function. Allows you, with the help of visualization tools, to analyze the performance of your PHP application and find bottlenecks. Shows which parts of your code base are executed when running unit tests with PHPUnit. Installing Xdebug with a package manager is often the fastest way. You can substitute the PHP version with the one that matches the PHP version that you are running. You can install Xdebug through PECL on Linux & macOS with Homebrew.
    Starting Price: Free
  • 7
    Defang

    Defang

    Defang

    Defang is a developer-centric platform that simplifies the process of developing, deploying, and debugging cloud applications. By leveraging AI-assisted tooling, Defang enables developers to swiftly transition from an idea to a deployed application on their preferred cloud provider. The platform supports multiple programming languages, including Go, JavaScript, and Python, allowing developers to start with sample projects or generate project outlines using natural language prompts. With a single command, Defang builds and deploys applications, handling configurations for computing, storage, load balancing, networking, logging, and security. The Defang Command Line Interface (CLI) facilitates interactions with the platform, offering installation options via shell scripts, Homebrew, Winget, Nix, or direct download. Developers can define services using compose.yaml files, which Defang utilizes to deploy applications to the cloud.
    Starting Price: $10 per month
  • 8
    Chrome DevTools
    Chrome DevTools is a set of web developer tools built directly into the Google Chrome browser. DevTools can help you edit pages on-the-fly and diagnose problems quickly, which ultimately helps you build better websites, faster. There are many ways to open DevTools, because different users want quick access to different parts of the DevTools UI. When you want to work with the DOM or CSS, right-click an element on the page and select Inspect to jump into the Elements panel. Or press Command+Option+C (Mac) or Control+Shift+C (Windows, Linux, Chrome OS). When you want to see logged messages or run JavaScript, press Command+Option+J (Mac) or Control+Shift+J (Windows, Linux, Chrome OS) to jump straight into the Console panel. Toggle various overlays and speed up DOM tree navigation with badges. The main uses of the Chrome DevTools Console are logging messages and running JavaScript.
    Starting Price: Free
  • 9
    Firefox Developer Tools
    Firefox Developer Tools is a set of web developer tools built into Firefox. You can use them to examine, edit, and debug HTML, CSS, and JavaScript. This section contains detailed guides to all of the tools as well as information on how to debug Firefox for Android, how to extend DevTools, and how to debug the browser as a whole. You can open the Firefox Developer Tools from the menu by selecting Tools > Web Developer > Web Developer Tools or use the keyboard shortcut Ctrl + Shift + I or F12 on Windows and Linux, or Cmd + Opt + I on macOS.
    Starting Price: Free
  • 10
    Backtrace

    Backtrace

    Backtrace

    Don’t let app, device, or game crashes get in the way of a great experience. Backtrace takes all the manual labor out of cross-platform crash and exception management so you can focus on shipping. Cross-platform callstack and event aggregation and monitoring. Process errors from panics, core dumps, minidumps, and during runtime across your stack with a single system. Backtrace generates structured, searchable error reports from your data. Automated analysis cuts down on time to resolution by surfacing important signals that lead engineers to crash root cause. Never worry about missing a clue with rich integrations into dashboards, notification, and workflow systems. Answer the questions that matter to you with Backtrace’s rich query engine. View a high-level overview of error frequency, prioritization, and trends across all your projects. Search through key data points and your own custom data across all your errors.
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