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Myers Shortest Edit Script (SES) Diff Engine

Online Text Diff Checker

Compare two texts by character, word, or line with our free online text diff checker. Get a similarity score and highlighted changes instantly in your browser.

Char, Word & Line ModesVisual Additions & DeletionsCode & Essay ComparisonZero-Latency Feedback100% In-Browser Privacy

Compare Text

Enter text above to see the difference...

Green Highlights

Text highlighted in green indicates additions. This is content that exists in the Modified Text, but was not present in the Original Text.

Red Highlights

Text highlighted in red with a strikethrough indicates deletions. This is content that was present in the Original Text but removed in the Modified Text.

Local Memory Sandbox
100% in-browser JavaScript memory
Diff Algorithm Engine
Myers Shortest Edit Script (SES) Parser
Comparison Standards
Granular Char, Word & Line Delimited Slicing
Quick Start

How to Compare Two Texts in 3 Steps

Spot edits, deletions, and additions between two text files or code drafts in three simple steps.

01

Paste Both Documents

Insert your original text in the left pane and your modified draft in the right pane.

02

Choose Comparison Mode

Select Words for essays, Chars for typos and subtle edits, or Lines for source code.

03

Inspect Highlighted Diff

Review green highlighted additions and red strikethrough deletions generated in real-time.

Architecture

Technical Comparison: In-Browser Diff vs Server-Side Compare Tools

How client-side Myers shortest edit script execution ensures absolute privacy and immediate feedback.

Comparison MetricUtilvo Client EngineServer-Based Diff Tools
Confidentiality & Privacy100% In-Browser Memory (0 Bytes Transferred)Sensitive Text Uploaded to Server Databases
Reactivity & Keystroke Diff< 1ms Instant Keystroke FeedbackRequires Form Submission / Network Roundtrip
Tri-Mode Token SlicingChars, Words, and Lines Toggleable LiveFixed Line-Diff Only (Misses Inline Edits)
Offline Capability100% Offline PWA ReadyCompletely Inoperable Offline
Document Size LimitHost RAM Limit Only (Multi-MB Strings)Strict Request Payload Caps (e.g., 20KB)
Capabilities

Engineering Architecture & Diff Specifications

Precision text comparison designed for software engineers, legal editors, and academic authors.

Myers Shortest Edit Script (SES)

Uses Eugene Myers' $O(ND)$ difference algorithm to compute minimal addition and deletion sequences. Guarantees the most intuitive and human-readable diff visualization possible.

Tri-Mode Granular Tokenization

Switch between Character mode for typos, Word mode for proofreading essays and manuscripts, or Line mode for source code, configuration files, and SQL schemas.

Side-by-Side Unified Feedback

Dual interactive textareas allow rapid editing and real-time re-diffing. High-contrast green addition badges and red strikethrough deletion markers update instantaneously.

Zero-Upload Privacy Sandbox

Confidential legal contracts, intellectual property, API tokens, and private essays remain strictly on your local machine. Nothing is ever logged or sent over a network.

Mode Guide

Diff Comparison Modes & Best Applications

Select the optimal tokenization granularity for your specific document type.

Comparison ModeGranularityBest Used ForVisual Output Sample
Word ModeSpace-Delimited WordsEssays, articles, agreements, translated textsquick brown fox
Char ModeSingle Characters & SymbolsTypos, spelling checks, punctuation, password checkstesxt
Line ModeNewline (\n) BoundariesGit patches, source code, JSON configs, CSV files+ const port = 3000;
FAQ

Frequently Asked Questions

Everything you need to know about Myers diff algorithms, token modes, and in-browser comparison privacy.

How does the Myers diff algorithm compare two documents?
Our diff engine implements Myers' algorithm and word/character tokenizer trees. It computes the shortest edit script (SES) between the original and modified strings, accurately isolating additions and deletions.
What is the difference between Character, Word, and Line diff modes?
Character mode detects fine differences down to individual keystrokes and typos. Word mode groups modifications into coherent linguistic tokens for prose and essays. Line mode highlights full line additions or removals, which is optimal for comparing programming code.
Is my sensitive code or document data private?
Yes, 100% confidential. The diff comparison executes entirely inside your browser's local memory via client-side JavaScript. No text snippets, contracts, or source code are ever uploaded or saved on external servers.
Can I compare code snippets and structured JSON or XML?
Yes. You can paste JSON, XML, HTML, CSS, JavaScript, Python, or SQL. Switching to Line mode gives you a git-like visual comparison of source code modifications.
What do the green and red highlights signify?
Green highlights represent newly added text found in the modified version. Red highlights with strikethroughs indicate text that was present in the original document but deleted or modified in the second version.
Is there a limit on text length or file size?
Because comparison is processed directly within client memory, there are no artificial server payload limits. You can compare multi-thousand-word essays, agreements, or large code scripts with near-instant rendering.
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