Compare two blocks of text or text files, review changes line by line, choose which side to keep for each change block, and build a merged output directly in your browser.
Input A — Left
Paste text or load a file.
Input B — Right
Paste text or load a file.
Merged Output
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Comparison and merging happen locally in this browser. Your text and files are not uploaded to Flipper File.
Online Text Diff and Merge Tool
This text comparison tool shows the differences between two text inputs or text files. It compares lines first, highlights changed text inside paired lines, and lets you choose the left or right version for each change block before building a merged result.
How to Compare Two Texts
- Paste text into Input A and Input B, or load two text-based files.
- Choose whether whitespace or letter case should be ignored during matching.
- Click Compare Text.
- Review the line-by-line difference view and inline highlights.
- Choose the left or right version for each change block.
- Build, copy, or download the merged output.
Line-Level and Inline Differences
The primary comparison is line-based so inserted and deleted lines remain aligned. When a left and right line occur in the same change block, the tool also compares smaller text tokens within those lines. This makes word and punctuation edits easier to identify without changing the source text.
Ignore Whitespace and Case
Ignore options affect comparison keys only. If two lines differ only in ignored whitespace or capitalization, they can be treated as unchanged, while their original text remains available for merge output. Ignoring whitespace collapses spaces and tabs and removes leading or trailing horizontal whitespace from the comparison key.
Merge Change Blocks
A two-way comparison has no common base document, so the tool does not try to guess which revision is semantically correct. Each changed block can use the left version or the right version. Auto-merge buttons apply the same choice to all changed blocks, while inline controls allow block-by-block decisions.
Large Text Comparisons
Full line alignment requires more work as both documents grow. For unusually large comparisons, the tool preserves the common beginning and ending and represents the changed middle as a simplified block instead of allocating an excessively large comparison matrix. The summary tells you when this mode is used.
Text Files and Encodings
The file loader accepts common text-oriented formats such as TXT, Markdown, JSON, JavaScript, HTML, CSS, CSV, XML, configuration files, and logs. UTF-8, UTF-8 with BOM, UTF-16 little-endian, and UTF-16 big-endian files are decoded locally.
Private Browser-Side Comparison
The diff algorithm, inline highlighting, merge choices, copy action, and text-file download all run in JavaScript in the browser. No comparison library, CDN asset, upload API, or server-side merge service is required.