Code Diff Checker — Compare Code Changes Online Free
Paste or upload two code files and instantly see every added, removed, or changed line highlighted. Monospace font, configurable tab expansion, and granular whitespace options make this the right tool for code review, patch inspection, and spotting regressions without opening an IDE.
Comparing Code Changes: What You Need to Know
Code diffs are the foundation of software collaboration. Every pull request, code review, and patch is fundamentally a structured answer to the question: "what changed?" TextCompare's code diff checker brings this capability to the browser without requiring a Git repository, IDE, or developer toolchain. Paste two snippets or upload two source files, and the diff engine computes the minimal edit distance between them using the Myers algorithm — the same engine that powers git diff.
Whitespace handling is critical for code. Many auto-formatters, linters, and editors introduce indentation changes, trailing-space cleanup, or tab-to-space conversions that have zero effect on program behavior but produce noisy diffs. Enable Ignore whitespace to suppress these cosmetic changes and focus on the logic that actually changed. Enable Expand tabs to render tabs as a fixed number of spaces so indentation aligns consistently regardless of the tab width set in each editor. The Tab size control lets you match the project's convention.
For comparing structured data like API responses or configuration files, the JSON Diff Checker adds automatic pretty-printing. For general text comparison, use the Diff Checker. To learn more about how the diff algorithm works under the hood, see How It Works.
Tips for Reading Code Diffs
Start with Unified View
Use unified view to scan all changes in a single column, similar to a standard patch file. Switch to split view when you need to see both versions simultaneously for context.
Enable Ignore Whitespace for Reformatted Code
When comparing files that were auto-formatted or had indentation changed, toggle "Ignore whitespace" to hide irrelevant changes and surface only logic modifications.
Use Word Diff for Long Lines
For long function signatures or chained method calls, switch to word diff mode to pinpoint exactly which argument, variable name, or operator changed on a line.
Download as .html for Sharing
The .html export preserves all color highlights and can be opened in any browser or shared as a self-contained file for code review documentation.
Frequently Asked Questions
A code diff checker compares two versions of source code and highlights every added, removed, or changed line — identical to running git diff on the command line but displayed visually in a browser. TextCompare adds code-specific options like tab expansion and whitespace control to keep diffs clean and focused on meaningful changes.
Formatters, linters, and editors often change tabs to spaces, add or remove trailing whitespace, or reindent blocks without modifying program logic. These cosmetic changes create noisy diffs that hide the real modifications. Enabling "Ignore whitespace" suppresses these changes so you see only the lines where actual logic changed. "Expand tabs" normalizes tab characters to a set number of spaces for consistent visual alignment.
All of them. TextCompare works on any plain-text source file regardless of language: JavaScript, TypeScript, Python, Java, C/C++, C#, Go, Rust, Ruby, PHP, Swift, Kotlin, SQL, Bash, HTML, CSS, YAML, JSON, and more. The diff engine does not require language-specific parsing — it compares text content directly, which means it works equally well for any language you write in.