CodeUtility
Making your developer's life easier!

Learn, Practice and Run Code Online

18,295,570+ code runs by developers and learners worldwide

Write and run code in 15+ languages, learn with interactive lessons, solve coding challenges with AI feedback and use free developer tools, all in your browser.

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Run Code Online in Popular Languages

Python

Run Python 3.x code online

4,345,332 runs
C++

Compile and run C++ programs

2,435,119 runs
C

Compile and run C language code

1,313,633 runs
Java

Compile and run Java programs online

261,131 runs
C#

Run C# code online with .NET support

373,061 runs
Matplotlib

Visualize Python charts with Matplotlib

577,069 runs
Coding in the age of AI

Why learn to code when AI can write it?

AI can type code faster than any of us, but it can't think for you. Learning to program trains the way you reason, shows you how software really works and prepares you to design whole systems, which is exactly what makes AI useful in your hands.

Train logical thinking

Programming teaches you to break a problem into small, precise steps and reason about every case. That way of thinking helps far beyond code.

Understand how things work

Memory, data structures, algorithms and complexity explain why code is fast or slow, correct or fragile. AI gives you answers; principles tell you which ones are right.

Design systems

AI writes pieces of code, but someone has to decide how the pieces fit together: the data, the architecture and the trade-offs. That skill is built on strong fundamentals.

Judge and fix AI code

AI code can look perfect and still be wrong, slow or insecure. Understanding code lets you review it, catch problems and fix them when something breaks.

CodeUtility helps you build that foundation: learn the concepts step by step, practise with challenges, and let AI act as a coach that reviews your code instead of writing it for you.

New · Coding Challenges

Level up with coding challenges

Solve hands-on programming problems in Python, C++, or C# right in your browser. Get instant test results and an AI code review, then compare your approach with the community.

Solve in your language

Write solutions in Python, C++, or C# with the same editor and workspace you use to run code.

Instant automated tests

Submit and see results for every test right away, with expected and actual output for each failure.

AI code review

Every passing solution gets an AI rating on correctness, readability, efficiency, and language practices.

Learn from the community

Read other developers' solutions and AI reviews, then join the discussion once you've solved the challenge.

226
Challenges
128
Solutions shared
9
Languages
Start a challenge

Popular challenges to start with

One place for your coding journey

Everything you need to learn and build

From your first line of code to machine learning from scratch, CodeUtility brings an online compiler, structured lessons, coding challenges and developer tools together, free and with nothing to install.

Online Compiler

Run Python, C, C++, C#, Java, JavaScript, Go, Rust and more instantly, with multi-file projects, a debugger, a terminal and AI help.

15+ languages Open →

Coding lessons

Learn Python, C/C++ and C# step by step with short lessons, runnable code, interactive diagrams and guided learning paths.

231 lessons PythonC/C++C#

Learn AI

Understand neural networks, machine learning, Transformers and reinforcement learning by building them yourself, without AI libraries.

4 learning paths Open →

Coding challenges

Practise with challenges in Python, C++ and C#. Get instant test results and an AI code review, then compare with the community.

226 challenges Open →

Developer tools

Beautify, minify, convert and encode code with free online tools for JSON, HTML, CSS, JavaScript, SQL and more.

Free Open →

Tech articles

Read tutorials and programming insights that explain concepts, tools and best practices in plain words.

Tutorials Open →
More than an online compiler

A complete coding workspace in your browser

Move from a quick snippet to a multi-file project without changing tools. CodeUtility combines flexible runtimes, a capable editor, persistent files, and built-in assistance.

Run where it fits

Use an isolated execution server with full workspace access, or run supported languages locally in a browser worker. Stop long runs and switch modes when needed.

AI coding assistance

Ask the AI assistant to explain the active program, clarify unfamiliar logic, and revisit recent explanations and assisted results from the editor.

Debug and fix code

Set breakpoints and step through supported browser runtimes, then use Fix Code to identify problems and apply a suggested repair without leaving the editor.

Professional code editor

Work with syntax highlighting, multiple tabs, search and replace, formatting, configurable themes and fonts, plus focused Minimal and full Advanced layouts.

A real multi-file workspace

Create files and folders, upload or download assets, and let programs interact with workspace files. Signed-in users can keep projects available across sessions.

Share and collaborate

Share a file, directory, or complete workspace as a snapshot or live project, with access controls, saved activity, chat, and collaborative editing.

Install libraries and packages

Inspect what is already preinstalled, then add private packages for your account and selected runtime. Cached downloads make repeated setup faster.

Code and run history

Revisit revisions of the active file and move through saved run outputs. Compare earlier work and copy a previous result without running the program again.

Interactive terminal

Enter standard input while a program runs, watch output as it arrives, copy results, and stop long-running jobs directly from the executor.

Browser execution and debugging depend on the language and runtime. Persistent workspaces and some assisted features require sign-in, and usage limits apply.