Free AI Code Assistant – Write, Debug, Explain

What the code assistant does

Paste code, an error message or a description of what you need, and pick a task. The assistant can write new code, hunt down bugs, explain code section by section, review it for problems, write unit tests, refactor for readability, or convert code from one programming language to another. Every piece of code comes back in a formatted block with a short explanation.

It runs on Grok 4.20, which answers quickly and is a solid everyday coding partner. Its instructions ask for complete, runnable code, a stated cause before each fix, and honesty about uncertainty: it should never invent functions or packages, and when an answer depends on a library version or code it cannot see, it should tell you what to check.

How to use it

Paste your code or describe the task. For a bug, include the full error message and say what you expected to happen.
Choose a task: Write code, Find and fix bugs, Explain code, Review code, Write tests, Refactor, or Convert to the language below.
Choose a language. Detect automatically works for most pasted code. The list covers 18 languages, including Python, JavaScript, TypeScript, Java, C#, C++, Go, Rust, PHP, Kotlin, Swift, Dart, SQL, Bash, PowerShell, and HTML with CSS. For conversion, this is the language you want to end up with.
Generate, then copy the code, regenerate, or press Continue in chat to keep iterating with the context intact.

Tips for better answers

Give the smallest code that shows the problem. Twenty lines that reproduce a bug beat two thousand lines of project.
Mention versions. "Python 3.12, pandas 2" or "React 19" prevents answers written for an older API.
Paste errors exactly. The stack trace usually points straight at the cause; a paraphrase of it rarely does.
Ask for tests with the fix. A failing test that passes after the change is the best proof the fix works.
Switch models for hard problems. In the chat, Grok 4.3 Thinking reasons before answering and is a better fit for tricky algorithms or subtle bugs. Grok 4.7, the newest model, is there too, with a smaller daily limit.

Example

The second sample under the box is a classic bug:

nums = [3, 8, 11, 14, 20]
for n in nums:
    if n % 2 == 1:
        continue
        print(n)

Step	What a good answer says
Cause	`print(n)` is indented under `continue`, so it sits inside the `if` block after the jump and can never run.
Fix	Move `print(n)` back one level so it runs for every number that is not odd.
Result	The loop prints 8, 14 and 20.

Limits and safe use

Run and test everything. AI-generated code can look right and still fail on edge cases. Treat it like code from a colleague: review it before it goes anywhere important.
It cannot run your code. The assistant reasons about code but does not execute it, and it cannot see your files, your environment or your database.
Knowledge has a cut-off. Brand-new library releases may be unknown to it. When in doubt, compare with the official documentation.
Never paste secrets. API keys, passwords, tokens and connection strings should be removed or replaced with placeholders. Your input goes through our server and OpenRouter to the model.
Security matters. For authentication, payments or anything that handles personal data, have the code reviewed by someone experienced.

Code Assistant FAQ

Is the code assistant free?

Yes, and no account is needed. Each request counts toward the 30 free messages you get daily for the whole site.

Can I ask questions in a language other than English?

Yes. Explanations come back in the language you write in, while the code itself stays code. Comments inside the code usually follow your language too.

Can it build a whole app?

It can write individual functions, components, scripts and queries well. A full application needs planning, many files and testing, which works better step by step in the chat. Our guide to Grok for coding shows a practical workflow.

Can I send a screenshot of an error?

Not on this page, which accepts text. In the chat you can attach a screenshot, since all three models read images, but pasted text is still more reliable for code.

What should I do when the answer is wrong?

Tell it what happened when you ran the code, including the new error, and ask again. If you are stuck on an error, try this prompt: explain an error and its likely causes. Students learning to program can also use the Homework Helper in hints mode.