What is code comparison?
Code comparison (often called a diff or code compare) shows the differences between two versions of text or source. Green-style additions and red-style removals help you spot what changed. Searchers looking for “code compare,” “code comparison tools,” or “compare two code files” usually want a fast browser diff, not a full Git client.
How it works
Paste the original (left) and modified (right) code. The tool builds a side-by-side diff: matching lines stay aligned, removals appear on the left, additions on the right, and word-level highlights call out edits within a line. You can ignore whitespace when indentation-only noise is getting in the way. Navigate change hunks to jump between differences. There is no language-specific syntax highlighting theme — the focus is accurate line and word diffs for any text-based code.
How to use Code Comparison Tool
- Paste the older or “before” code into the left panel.
- Paste the newer or “after” code into the right panel.
- Scan highlighted additions and removals; use hunk navigation if the diff is long.
- Turn on ignore-whitespace when you only care about substantive changes.
- Copy either pane when you need to keep a cleaned-up version.
Worked examples
Concrete numbers and cases you can check against the tool above.
Staging vs production JSON config
Pretty-print both blobs first (the JSON formatter helps), then diff. A one-line minify vs pretty-print will look like the entire file changed. Line numbers make it obvious whether a key was added or a value flipped from true to false.
Indent-only noise with ignore whitespace
If one side was auto-formatted, every line can look “changed.” Enable ignore whitespace to focus on real edits — renamed keys, new conditions, deleted imports — instead of spaces and tabs.
What this tool does and does not do
It compares two pasted snippets with line numbers, added/removed highlighting, inline word highlights, hunk navigation, and an ignore-whitespace option. It does not clone Git repositories, merge conflicts, or apply language-aware AST diffs. For whole-project history, use Git; for two blobs of text, this code compare view is enough.
Tips for cleaner diffs
Pretty-print JSON or format code the same way on both sides before comparing — otherwise minified vs formatted text looks like every line changed. Align line endings when possible. If you only need prose differences, the Text Diff tool may be a better fit.
When to use Code Comparison Tool
IDE diffs are great inside a repo; this page is for pasted snippets from chat, tickets, or staging vs production configs when you do not want to create a branch just to see what changed. Everything runs in the browser so proprietary code is not uploaded.
Common use cases
- Compare nginx, JSON, or env configs between staging and production.
- Review a hotfix snippet someone sent in chat.
- Diff two versions of a function before merging a pull request discussion.
- Check classmate or interview solutions against a reference implementation.
Inputs and outputs
- Plain text / source code of any language
- Side-by-side diff with line numbers and inline change highlights
- Optional ignore-whitespace comparison
Privacy
Diffing runs entirely in your browser. Code you paste is not uploaded to our servers.
Frequently asked questions
- Which programming languages are supported?
- Any text-based code. The diff is based on lines and words, not a language parser, so JavaScript, Python, JSON, YAML, and configs all work the same way.
- Can I compare whole repositories?
- No. This is a snippet-level online code comparison tool, not a full Git repository diff viewer.
- Is syntax highlighting included?
- The viewer highlights additions and removals (and inline word changes). It does not apply a full language syntax color theme.
- Is my code uploaded?
- No. Comparison happens locally in your browser.