See AI Code Assistant — Debug, Explain & Write Code Free in action
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.
Use it in 4 steps
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.
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.
A real example, step by step
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.
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.
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.
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.
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.
Free, fast and private by design
No signup, no watermark. New AZRS tools are added every week.
