Debugging Tools Guide: 13 Tools to Fix Bugs Faster

Debugging tools have evolved from rudimentary catch-all software into specialist solutions for different languages, userbases and development stages. The best debugging strategies choose the right tool for their specific use case, and this guide will help you do that.

We’ll give you the knowledge to:

• Break down debugging tools based on where issues actually occur.
• Identify the right tool for each stage of the workflow.
• Maximise the tools provided by Chrome, Firefox and other browsers.

We’ll mention our own product in this list, but don’t worry: the content you’ll find here is impartial, comprehensive and educational, not salesy.

How to choose the right debugging tool

Choosing the right debugging tool is actually very simple: Start where the issue appears, validate assumptions early, and only move deeper if needed.

This table gives you a top-line overview of the various stages, and the specific tools you can apply to each of them.

Problem / stack	Start with
UI / frontend issues	Chrome DevTools
Layout / CSS issues	Firefox DevTools
API / backend debugging	Postman
Quick API testing	Insomnia
Code logic issues	Visual Studio Code or IntelliJ IDEA
Backend (Java / complex apps)	IntelliJ IDEA
iOS / mobile debugging	Xcode
Network / HTTP traffic issues	Fiddler
Mobile / cross-device traffic	Charles Proxy
Crashes / memory issues	GDB
Windows system debugging	WinDbg
Network packet analysis	Wireshark
Production / real user issues	Bugfender

These tools are not alternatives to one another, but complementary solutions for different layers of the system.

Most issues start at the frontend or API level, so we’ll begin with browser debugging tools before moving deeper into code, network, and system-level debugging.

Debugging frontend and browser tools

Frontend bugs appear directly in the browser. This makes them highly visible to our users, but it also allows us to take advantage of browser DevTools.

Most modern browsers include built-in DevTools which let us analyze what users actually see and interact with, making them essential for fixing client-side issues quickly.

They are best used when dealing with:

• Layout or CSS issues affecting the UI.
• JavaScript errors and unexpected behavior.
• Slow loading or performance bottlenecks.
• Network request failures or API response problems.

By working directly in the browser, we can test fixes instantly, inspect live elements, and trace issues without rebuilding or redeploying the application.

Note that Chromium-based browsers (Chrome, Edge, Opera) share similar tools, while Firefox provides a different implementation with stronger layout inspection.

Chrome DevTools

Chrome DevTools is a built-in browser debugging tool for inspecting, testing, and modifying frontend code in real time.

Best for: debugging UI, JavaScript, and network issues directly in the browser**.**

Key functions:

• Inspect and edit HTML and CSS live.
• Debug JavaScript with breakpoints and call stacks.
• Monitor network requests and API responses.
• Analyze performance, load times, and rendering.

Common use case: tracking why a button click doesn’t trigger an API request or returns an unexpected response.

Limitation: Limited to client-side debugging and browser environment only.

For a deeper walkthrough, see our guide to Chrome DevTools.

Firefox DevTools

Firefox DevTools is a built-in browser debugging tool similar to Chrome DevTools, allowing you to inspect and edit HTML/CSS, debug JavaScript, and monitor network activity in real time.

Best for: debugging layout, CSS, and UI rendering issues with more precise visual tools.

Key functions:

• Examine the layout structure via the visual grid and flexbox overlays.
• Conduct detailed CSS inspection (including computed and applied styles).
• Analyze spacing, alignment, and box model issues with the Layout panel.
• Visualize stacking, alignment, and element relationships.

Common use case: fixing complex layout issues (grid, flexbox, spacing) that are difficult to understand in Chromium-based DevTools.

Limitation: Smaller ecosystem and less commonly used in typical development workflows.

For more details, see the official documentation: https://firefox-source-docs.mozilla.org/devtools-user/.

Debugging API and backend tools

API and backend issues happen behind the UI, where requests may fail silently or return incorrect data without obvious visual clues.

API platforms like Postman and Insomnia allow us to root out these problems by inspecting and testing communication between services. They are best used to deal with:

• Failing or slow API requests.
• Incorrect request payloads or headers.
• Unexpected or malformed responses.
• Authentication and authorization issues.

By sending and analyzing requests independently, we can isolate backend problems, verify behavior, and identify whether the issue comes from the server or the client integration.

Postman

Postman is an API debugging tool for sending, testing, and inspecting HTTP requests and responses without a frontend.

Best for: testing API endpoints, validating requests, and debugging backend communication.

Key functions:

• Send requests with custom methods, headers, and payloads.
• Inspect responses (status, body, headers, timing).
• Save and organize requests into collections.
• Automate tests and reuse environments (tokens, variables).

Common use case: reproducing a failing API call to check whether the issue comes from the backend or the frontend integration.

Limitation: Can become complex with large collections or advanced workflows.

For more details, visit the official website: https://www.postman.com/

Insomnia

Insomnia is an API debugging tool designed to send and test HTTP requests with a fast, lightweight interface.

Best for: quickly testing API endpoints and debugging requests without complex setup.

Key functions:

• Create and execute HTTP, REST, GraphQL, gRPC, SOAP, WebSocket, or SSE requests.
• Use environment variables to test the same request against development, staging, or production servers.
• Automate authentication (such as refreshing OAuth tokens).
• Generate client code from working requests.

Common use case: quickly testing an API endpoint or debugging a request without managing large collections or complex workflows.

Limitation: Fewer advanced collaboration and automation features compared to Postman.

For more details, visit the official website: https://insomnia.rest/.

Debugging code inside IDEs

While browser and API tools show how an application behaves, IDE debugging tools reveal how the code actually executes at a granular level.

Tools like Visual Studio Code, IntelliJ IDEA, and Xcode allow us to run code step by step, inspect variables, and follow execution flow directly from the source.

They are best used to deal with:

• Logical errors in functions or application flow.
• Incorrect variable values during execution.
• Bugs that don’t surface clearly in the UI or API response.
• Complex conditions, loops, or branching logic.

By debugging inside the IDE, we can trace exactly how the code runs before it reaches the browser or external systems, making it easier to identify root causes rather than symptoms.

Visual Studio Code

Visual Studio Code is a code editor with a built-in debugger for running, inspecting, and stepping through code across multiple languages.

Best for: debugging application logic within the development environment.

Key functions:

• Set breakpoints and pause execution.
• Inspect variables, call stack, and execution flow.
• Step into, over, and out of functions.
• Debug multiple languages through extensions.

Common use case: tracing a function that returns unexpected results by stepping through each line and checking how variables change.

Limitation: Requires proper configuration (launch settings, extensions) depending on the language and environment.

For more details, visit the official website: https://code.visualstudio.com/.

IntelliJ IDEA

IntelliJ IDEA is a full-featured IDE with advanced debugging tools to analyze code execution in Java and JVM-based applications.

Best for: debugging complex backend logic in Java, Kotlin, and other JVM languages.

Key functions:

• Inspect variables and perform smart code analysis.
• Step through debugging with detailed call stack insights.
• Evaluate expressions during runtime.
• Integrate with build tools (Maven, Gradle).

Common use case: debugging a backend service where multiple methods and dependencies interact, helping to trace how data flows across layers.

Limitation: Heavier and more resource-intensive than lightweight editors like Visual Studio Code.

For more details, visit the official website: https://www.jetbrains.com/idea/.

Xcode

Xcode is Apple’s IDE, with built-in debugging tools for running, inspecting, and analyzing iOS and macOS applications. It integrates LLDB, the LLVM project’s source-level debugger, allowing developers to pause execution, step through code, inspect variables, memory, threads, and the call stack, and diagnose crashes and runtime issues.

Best for: debugging Swift and Objective-C code in iOS apps and testing behavior on simulators or real devices.

Key functions:

• Conduct step-by-step code execution using LLDB.
• Inspect variables, memory, and runtime state.
• Debug UI and app lifecycle directly in the simulator.
• Analyze performance, memory usage, and crashes.

Common use case: debugging an iOS app where a view doesn’t update correctly or a crash occurs only on a specific device or state.

Limitation: Limited to Apple platforms and tightly coupled with the Apple development ecosystem.

For more details, visit the official website: https://developer.apple.com/xcode/.

Debugging network and traffic issues

Some issues don’t come from the code itself, but from how data moves between the client, server and external services. Network and traffic debugging tools help us inspect, intercept and analyze requests as they travel between these systems.

These tools show what is actually sent over the network, not what the application assumes is happening.

They are best used to deal with:

• Failed or inconsistent API calls across environments.
• Unexpected request or response behavior.
• Issues with headers, cookies, or authentication tokens.
• Third-party integrations that behave differently in production.

By analyzing traffic in transit, we can understand what is actually being sent and received, verify data integrity, and identify issues that are not visible inside the application code or UI.

Fiddler

Fiddler is a web debugging proxy for capturing, inspecting, and modifying HTTP and HTTPS traffic between a client and server.

Best for: analyzing real network requests across applications and debugging issues that don’t appear in the browser alone.

Key functions:

• Capture all HTTP/HTTPS traffic from the system.
• Inspect headers, cookies, and request/response data.
• Modify requests and responses before they reach the server.
• Replay requests to test different scenarios.

Common use case: debugging an authentication issue by inspecting cookies or headers sent from an application and verifying what the server actually receives.

Limitation: Primarily optimized for Windows environments and requires configuration for HTTPS decryption.

For more details, visit the official website: https://www.telerik.com/fiddler.

Charles Proxy

Charles Proxy is a web debugging proxy for capturing, inspecting, and modifying HTTP and HTTPS traffic across applications and devices.

Best for: debugging network requests on mobile devices and testing real app behavior across environments.

Key functions:

• Capture traffic from desktop and mobile devices (iOS, Android).
• Inspect and modify requests, headers, and responses.
• SSL proxying to debug HTTPS traffic.
• Simulate network conditions (latency, bandwidth throttling).

Common use case: debugging a mobile app API issue by routing device traffic through Charles to inspect requests and responses in real time.

Limitation: Requires manual proxy setup and certificate installation for HTTPS inspection.

For more details, visit the official website: https://www.charlesproxy.com/

Debugging system-level and low-level issues

Some bugs don’t originate in the application itself, but in how the system executes code, manages memory or handles communication between processes. These issues often require tools that operate closer to the operating system and network layers, such as GDB, WinDbg and Wireshark.

Depending on where the issue occurs, different tools are used to inspect code execution, system behavior or network communication.

They are best used when dealing with:

• Application crashes, segmentation faults, or core dumps.
• Memory corruption or unexpected low-level behavior.
• Operating system or process-level failures.
• Network communication issues not visible at the application level.

By debugging at this level, we can investigate the root cause of failures that higher-level tools usually only surface as symptoms.

GDB

GDB (GNU Debugger) is a low-level debugging tool to analyze how programs execute at machine level, especially in C and C++ applications.

Best for: debugging crashes, segmentation faults, and memory-related issues in compiled programs.

Key functions:

• Step through code line by line during execution.
• Inspect variables, memory, and registers.
• Analyze core dumps after crashes.
• Trace function calls and execution flow.

Common use case: investigating a segmentation fault by stepping through the program and identifying where invalid memory access occurs.

Limitation: Command-line interface with a steep learning curve compared to modern IDE debuggers.

For more details, visit the official website: https://www.gnu.org/software/gdb/.

WinDbg

WinDbg is a low-level debugger from Microsoft for analyzing Windows applications, system processes and crash dumps.

Best for: debugging system crashes, memory issues, and Windows-specific failures.

Key functions:

• Analyze crash dumps (BSOD and application crashes).
• Inspect memory, threads, and system state.
• Debug user-mode and kernel-mode applications.
• Advanced diagnostics with symbols and extensions.

Common use case: investigating a Windows application crash by analyzing a dump file to identify the root cause.

Limitation: Complex interface and steep learning curve, especially for kernel-level debugging.

For more details, visit the official website: https://learn.microsoft.com/en-us/windows-hardware/drivers/debugger/.

Wireshark

Wireshark is a network protocol analyzer for capturing and inspecting data packets traveling across a network in real time.

Best for: debugging network communication issues that are not visible at the application or API level.

Key functions:

• Capture and analyze network packets in real time.
• Inspect protocols (HTTP, TCP, DNS, etc.) in detail.
• Filter traffic to isolate specific requests or connections.
• Identify latency, dropped packets, or unexpected responses.

Common use case: investigating why a service fails to communicate by analyzing whether requests are sent, received or blocked at the network level.

Limitation: Can be overwhelming due to the volume of data and requires understanding of networking concepts.

For more details, visit the official website: https://www.wireshark.org/.

Debugging production issues with logs and real user data

Some bugs only appear when your code runs in the real world, with real users, devices, and data. These issues are often impossible to reproduce locally because they depend on conditions you don’t fully control.

Production debugging tools focus on capturing what actually happens in live environments, not what we assume is happening.

Unlike browser, API, or IDE tools, they reveal issues that only emerge under real user conditions.

They are best used when dealing with:

• Issues that cannot be reproduced in development or staging
• Errors reported by users without clear steps to reproduce
• Crashes or inconsistent behavior across devices
• Missing context about user actions and environment

By collecting logs, events, and context directly from production, we can trace issues back to real conditions and fix problems based on evidence instead of guesswork.

Bugfender

Bugfender is a remote logging and error monitoring tool that collects logs, crashes, and user context directly from production devices.

This is our solution (you probably realised that) but we think it’s worth its place in this list. Bugfender was built by developers who were tired of guessing what happens on real user devices.

Best for: gaining visibility into real user sessions, including issues that don’t trigger crashes or errors.

Key functions:

• Continuous remote logging, even when the app is running normally.
• Device-centric view to track issues per user and session.
• Built-in error monitoring with stack traces and symbolication.
• Capture user actions and context alongside logs.
• Collect in-app user feedback with technical context attached.

Common use case: identifying silent failures, edge cases, and device-specific behavior that never appear in local testing or crash reports.

Limitation: Focused on mobile and frontend applications, so less relevant for purely backend systems.

Try Bugfender for free: https://dashboard.bugfender.com/signup

How to approach debugging in practice

Debugging becomes faster when you treat it as a process, not a tool.

• Start from where the issue appears
• Confirm what is actually happening, not what you expect
• Move one layer deeper only when needed

Most time is lost by jumping between tools instead of following the system step by step.

For a broader overview of debugging concepts and strategies, see our main guide to debugging.

Frequently asked questions about debugging tools

What are the most common debugging tools developers use?

Browser DevTools, API clients like Postman, IDE debuggers like Visual Studio Code or IntelliJ IDEA, traffic inspection tools like Charles or Fiddler, and production logging tools like Bugfender are among the most commonly used debugging tools.

What’s the difference between browser DevTools and IDE debugging tools?

Browser DevTools are used to debug code running in the browser (UI, JavaScript, network requests).

IDE debugging tools are used to debug the source code itself, allowing you to step through execution, inspect variables, and analyze logic before it reaches the browser.

What’s the difference between API tools and traffic inspection tools?

API tools like Postman or Insomnia send requests manually to test endpoints.

Traffic inspection tools like Fiddler or Charles capture real requests made by applications, allowing you to see and modify what is actually sent over the network.

Which debugging tools are best for mobile applications?

Mobile debugging usually requires a combination of tools:

• IDE tools (Xcode, Android Studio) for code and app behavior
• Proxy tools (Charles) for network requests
• Logging tools like Bugfender for real user issues in production

Do I need low-level debugging tools like GDB or Wireshark?

Only in specific cases.

Most day-to-day debugging can be done with browser, API, or IDE tools. Low-level tools are useful when dealing with crashes, memory issues, or network problems that aren’t visible at higher levels.