Code Explainer
Understand any code snippet in plain English with free AI — an overview, a step-by-step walkthrough, and bug or improvement notes. Any language.
Thinking…
Understand any code snippet in plain English. Paste a function or block in any language and the AI explains what it does overall, walks through the key parts step by step, and flags any bugs or improvements worth noting.
How to use Code Explainer
- Paste the code you want explained (any language).
- Click "Explain code" to get a plain-English breakdown.
- Read the overview and step-by-step walkthrough, and note any suggested fixes.
Who it is for
Code Explainer is for code you have to understand but did not write: an unfamiliar function in a codebase, a snippet from a library, a regex nobody wants to read, or something you wrote months ago. It is used to get from "what does this do" to "what does this do" in a minute.
How it works
- The AI explains what the block does overall, walks through the key parts, and flags bugs or improvements worth noting.
- Any language can be pasted in, since the explanation is about intent and structure rather than execution.
- Explanations are in plain English rather than restating the syntax.
What it cannot do
- It cannot run the code, so behaviour that depends on runtime state is inferred rather than known.
- It may confidently misread an unusual idiom or a language-specific nuance.
- Code is sent to a third-party AI provider — do not paste anything proprietary or containing credentials.
- It explains a snippet, not an architecture; a whole codebase needs more context than this gives.
Frequently asked questions
Which languages does it support?
Most common languages — JavaScript, Python, PHP, Java, C/C++, Go, Ruby, SQL, and more. Paste the snippet and it will detect the language.
Does it point out bugs?
Yes. Alongside the explanation it notes any bugs or improvements worth considering, so it doubles as a quick review.
Can it add comments to my code?
Yes. Ask it to comment the code and it will return your snippet with clear inline comments.
Is my code kept private?
Your code is sent securely only to generate the explanation and is not stored on our servers afterward.
Can I paste proprietary code?
You can, but you should not. The snippet is sent to a third-party AI provider, so anything under an NDA, or containing credentials, keys or customer data, should not be pasted — strip it first.
Can it find security flaws?
It may point out an obvious one, but it is not a security review and should not be treated as one. Use a scanner and a human reviewer for anything that matters.
Why does it sometimes misread my code?
It reads the text rather than running it, so behaviour that depends on runtime state, an unusual library or a language-specific idiom can be inferred incorrectly. Where the explanation matters, test the claim.