Free Code Reviewer & Refactoring Helper (No Signup Needed)

Use this code reviewer when you want a quick first pass before a pull request. It runs in your browser, so the code you paste stays on the page instead of going to an external worker.

What this code reviewer does

The tool scans a function or small file for a focused set of rule-based checks. It looks for formatting drift, long lines, repeated statements, TODO markers, and language-specific issues that often deserve a second look.

JavaScript and TypeScript checks include var declarations, loose equality, console output, long promise chains, and collection loops that may be clearer as array operations. Python checks include bare except blocks, comparisons with None, and leftover print calls.

How to use the refactoring helper

Keep the input small enough that you can judge every suggestion against the surrounding code and its tests.

1. Paste a small function or file into the editor.
2. Choose a focus when readability, maintainability, or bug risks matter more for the current change.
3. Read each finding, decide whether it fits the code’s intent, and make the change in your editor.
4. Run the test suite before you merge.

The Safe cleanup output only removes trailing whitespace and excess blank lines. It does not rewrite control flow, rename variables, or convert syntax automatically because those changes need context and tests.

Why browser-local review matters

Code snippets can contain customer data, internal URLs, feature flags, and business rules, so a local first pass keeps that text out of a hosted model or third-party review API.

You can confirm the behavior in the browser network panel because the page makes no review request after you click Review code.

What to check before a pull request

A static reviewer cannot infer product requirements or prove that a refactor preserved behavior, which makes each finding a prompt for inspection rather than a verdict.

Changes that touch authorization, payments, data deletion, concurrency, or database writes need a test, a diff review, and another developer’s judgment.

AI code reviewer versus this local checker

An AI code reviewer can propose broad rewrites and explain unfamiliar code, but it needs an external model and may not follow your repository’s conventions. The local checker stays narrow on purpose.

Each finding names the rule that triggered it, while semantic refactors remain changes you make and test in your own editor.

Common refactoring checks

These checks explain the kind of finding the local reviewer can surface. The right fix still depends on the code around it.

Loose equality in JavaScript

JavaScript coercion can hide a data-shape mistake, so prefer strict equality when values and types must match while preserving an intentional value == null check when you mean null or undefined together.

Function-scoped variables

Var declarations can make a binding visible farther than the code that uses it, so check whether const or let better describes the binding before changing it because var replacement can alter behavior in older code.

Bare exception handling in Python

An except block with no exception type can swallow interrupts and unrelated failures, so catch the failure you expect, add context to the error, and leave unexpected failures visible during development.

Frequently asked questions

Check the boundary before you use any automated review tool with repository code.

Does this tool upload my code?

No. The reviewer runs in the browser and does not call a model, worker, or review API.

Can it replace a human code review?

No. It can point out a small set of rule-based concerns, but it cannot validate product behavior, repository conventions, security boundaries, or test coverage.

Why does the cleanup output avoid a full rewrite?

A full rewrite can change behavior without enough context, so the output only applies whitespace cleanup and leaves refactors as suggestions you can assess in your editor and verify with tests.

Which languages does it support?

The general checks work for any pasted text. JavaScript, TypeScript, and Python have additional rules, while the language selector helps you label the review for the code you are reading.

Use the reviewer as a first pass

Run the tool while the change is still small enough to reason about. Fix the issue you agree with, discard the one that does not fit the code, and let the test suite decide whether the refactor earned its place.