Question 1

What is a Text Diff Checker and how does the underlying comparison algorithm work?

Accepted Answer

A Diff Checker identifies structural and line-level changes between two text or code files:

① Classic Myers Diff Algorithm:
Powered by the Myers Difference Algorithm (the same engine underpinning Git and standard version control systems), it calculates the Shortest Edit Script (SES) to find minimal edit sets.

② Visual Line & Character Highlights:
Clearly flags inserted, deleted, and unmodified lines with colored indicators, speeding up code reviews, legal contract auditing, and copywriting revisions.

Question 2

What is the difference between Split Mode (Side-by-Side) and Unified Mode?

Accepted Answer

Each view mode serves distinct review preferences:

① Side-by-Side Split View:
Displays the original and modified documents side-by-side with synchronized dual-pane scroll locking, perfect for examining structural layout shifts.

② Single-Pane Unified View:
Merges all revisions into a continuous single stream with red/green diff badges (similar to GitHub PRs and Git patch files), ideal for line-by-line inspection.

Question 3

Is it secure to paste proprietary code, legal contracts, or sensitive text into this online tool?

Accepted Answer

100% Secure! The tool operates strictly as a client-side web application in your browser:

① Zero Backend Transmission:
All diff calculations and syntax rendering occur purely within your computer memory.

② Zero Cloud Logging:
No text, files, or metadata are ever uploaded to remote servers. The tool functions completely offline.

Question 4

What does the "Ignore Case" option do, and when should it be toggled on?

Accepted Answer

Toggling case-insensitivity alters match semantics:

① Disregarding Capitalization:
Treats `Apple` and `apple` as identical tokens without flagging them as differences.

② Best Use Cases:
Ideal for SQL queries, HTML markup, configuration files, or general copy editing where letter case does not affect technical semantics.

Question 5

What file types are supported for drag-and-drop file imports? Are there file size limits?

Accepted Answer

Our tool accepts a wide range of plain text and developer source files:

① Supported Formats:
Text documents (`.txt`, `.md`, `.json`, `.csv`, `.xml`, `.yaml`) and programming source files (`.js`, `.ts`, `.py`, `.java`, `.go`, `.cpp`, `.css`, `.html`, etc.).

② Performance Guideline:
We recommend files under 10MB (several hundred thousand lines) to preserve 60fps browser rendering responsiveness.

Question 6

How does the interactive "Merge Diff" workflow operate in Unified Mode?

Accepted Answer

A built-in interactive reconciliation engine:

① Custom Line Selection:
In Unified mode, click any modified line to toggle between "Active (Kept)" and "Skipped" states to curate your final revision.

② One-Click Merged Export:
Click "Copy Merged Result" or "Export Merged File" to instantly generate a unified resolved document.

Question 7

How can I quickly swap comparison directions or reset the workspace?

Accepted Answer

Productivity toolbar shortcuts:

① Swap Button:
Instantly swap the Original and Modified buffers without manual cut-and-paste.

② Focus Mode & Clear:
Toggle "Show Diff Only" to maximize the comparison pane or use "Clear" to wipe both editors.

Document Diff Checker

Diff Analysis Result

Frequently Asked Questions (FAQ)7 Q&As