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Code Assistant
Preview
See AI Code Assistant — Debug, Explain & Write Code Free in action
1Open Code Assistant and paste your code into the left panel.
2Pick an action — Explain, Fix, or Optimise.
3Add any extra context (an error message, what's not working) if relevant.
Overview
AI Code Assistant — Debug, Explain & Write Code Free
Code Assistant is a focused coding companion: paste in a snippet and ask it to explain what the code does, find and fix a bug, or optimise it — tuned with a 'senior engineer' system prompt that pushes for complete, working code with error handling rather than half-finished examples.
It works across any mainstream language — Python, JavaScript, Java, C++, SQL and more — and always returns full code blocks so you can copy-paste a fix directly, rather than a vague description of what to change.
Highlights
Key features
Explain code
Paste any snippet and get a clear, line-by-line breakdown of what it does.
Fix / debug
Paste broken code and an error message and get back the corrected, complete version.
Optimise
Ask for a faster or cleaner version of working code, with complexity notes.
Any language
Python, JavaScript, Java, C++, SQL, and most other mainstream languages.
Walkthrough
How to use it
- Open Code Assistant and paste your code into the left panel.
- Pick an action — Explain, Fix, or Optimise.
- Add any extra context (an error message, what's not working) if relevant.
- Read the AI's full response, including the corrected/optimised code block.
In practice
Worked example
Example
Paste a Python function that throws 'IndexError: list index out of range', hit Fix, and get back the corrected function with a bounds check added and a one-line explanation of what was wrong.
Audience
Who uses this tool
Students learning to code
Get plain-language explanations of unfamiliar code instead of just the fix.
Developers debugging quickly
Paste an error and get a real fix without leaving the browser.
Anyone reviewing someone else's code
Understand an unfamiliar snippet fast before making changes.
Pro tips
Tips for the best results
- Include the actual error message/traceback, not just 'this doesn't work' — it makes the fix far more accurate.
- Paste the whole function, not just the broken line — the AI needs context to trace the real bug.
- For style/performance improvements, ask for optimise specifically rather than a general explain.
- If a fix doesn't fully resolve it, reply with what happened next — the conversation carries context forward.
Watch out
Common mistakes to avoid
- Pasting only the error message without any of the surrounding code.
- Asking for a fix in one language while the pasted code is written in another (mismatched language context confuses the response).
- Not testing the returned code before using it in a real project — always run and verify.
Why AZRS
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
FAQ
Frequently asked questions
What languages are supported?
Any mainstream language — Python, JavaScript, TypeScript, Java, C++, C#, Go, SQL and more.
Can it fix runtime errors, not just syntax errors?
Yes, paste the code plus the actual error/traceback and it will diagnose and fix logical or runtime bugs too.
Is it free to use?
Yes, unlimited and free.
Does it explain WHY the bug happened?
Yes, fixes come with a short explanation of the root cause, not just the corrected code.
Can I ask it to optimise working code?
Yes, use the Optimise action for a faster or cleaner version with complexity notes.
Does it store my code?
Code you paste is sent to the AI provider to generate a response; it isn't published or shared anywhere on the site.