What Is a Code Diff Checker?
A code diff checker compares two blocks of text or code and highlights the differences between them. It shows additions, deletions, and modifications line by line, similar to how version control systems like Git display changes.
How to Use This Code Diff Checker
- Paste both code blocks into the single input area, separated by a line containing only
---. Everything above the separator is treated as the original code, and everything below is the modified code. - Click Compare to compare the two sections.
- The output displays a unified diff with line numbers, additions (
+), and deletions (-), followed by a summary of total changes.
Key Concepts
Diff algorithms compare text using techniques like the Longest Common Subsequence (LCS) algorithm. Lines present only in the original are marked as deletions (typically red), lines only in the modified version are additions (typically green), and unchanged lines provide context. This is the same logic powering Git diff, pull request reviews, and code review tools.
Frequently Asked Questions
Can I compare any text, not just code?
Yes. The diff checker works with any plain text including prose, configuration files, CSV data, and log files. It compares line by line regardless of content type.
Does it detect moved lines?
Standard diff shows moved lines as a deletion and a separate addition. Some advanced diff tools detect moves, but the basic algorithm treats each line independently.
How does it handle whitespace differences?
By default, all whitespace differences are shown. Many diff tools offer options to ignore trailing whitespace or all whitespace changes for cleaner comparisons.