COMPARE TWO TEXTS SIDE BY SIDE · HIGHLIGHT ADDITIONS & DELETIONS
📝 ORIGINAL TEXT
📝 MODIFIED TEXT
Ignore Case
Ignore Whitespace
Char-level Diff
Show Unchanged Lines
0 added0 deleted0 unchanged0% similar
ORIGINAL
MODIFIED
Free Diff Checker – Compare Two Texts or Files Online
By RapidTool Team · Last updated: September 2026
Our free diff checker lets you compare any two pieces of text side by side and instantly see what changed. Additions are highlighted in green, deletions in red, and unchanged lines appear normally. Ideal for comparing code versions, document revisions, config files, or any text where you need to spot differences quickly.
Common Uses for Diff Checking
Software developers use diff tools to review code changes before commits. Writers use them to compare document versions. DevOps engineers use diffs to compare configuration files. Researchers use text comparison to find changes between document revisions. Our tool works for any plain text, JSON, XML, HTML, CSS, JavaScript, or prose content.
Frequently Asked Questions
What algorithm does this diff checker use?
This tool uses a line-by-line LCS (Longest Common Subsequence) diff algorithm — the same approach used by Git and Unix diff tools. It finds the minimum number of insertions and deletions needed to transform one text into another.
Can I compare code files with this tool?
Yes, absolutely. The tool compares plain text content, which includes source code, JSON, XML, HTML, CSS, SQL, Markdown, and any other text-based format. Just paste the contents of both files into each panel.
What's the maximum text size I can compare?
The tool handles texts of several thousand lines comfortably. Very large files (100,000+ lines) may be slow depending on your device. For large files, consider comparing specific sections or using a dedicated tool like git diff or vimdiff.