Text Diff Checker – Compare Text & Code Online

Compare two text files or code snippets side-by-side with Split and Unified views, line differences, and addition/deletion highlighting.

Diff View:

Original Text (Old):8 lines

function processOrder(orderId, items) {
  console.log("Processing order: " + orderId);
  let total = 0;
  for (let i = 0; i < items.length; i++) {
    total += items[i].price;
  }
  return total;
}

Modified Text (New):9 lines

function processOrder(orderId, items, discount = 0) {
  console.log(`Processing order #${orderId}`);
  let total = 0;
  for (const item of items) {
    total += item.price;
  }
  const finalTotal = total - (total * discount);
  return Math.max(0, finalTotal);
}

Case-sensitiveIgnore whitespace

+6 added-5 removed3 same

Visual Diff Inspection Results:

-Original (Old)
+Modified (New)
-function processOrder(orderId, items) {
+function processOrder(orderId, items, discount = 0) {
-  console.log("Processing order: " + orderId);
+  console.log(`Processing order #${orderId}`);
   let total = 0;
-  for (let i = 0; i < items.length; i++) {
+  for (const item of items) {
-    total += items[i].price;
+    total += item.price;
   }
-  return total;
+  const finalTotal = total - (total * discount);
+  return Math.max(0, finalTotal);
 }

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How to Compare Text Differences Online

Paste Original and Modified Text

Paste your base text into the left "Original Text" box and your updated version into the right "Modified Text" box.

Choose View Mode and Options

Switch between Split View (2 columns) or Unified View, and toggle Case-sensitive or Ignore whitespace as needed.

Inspect Highlights and Copy Patch

Review green additions (+) and red deletions (-), then copy the unified diff or summary report with one click.

Diff Views & Git Patch Notation Guide

Understand the differences between Split and Unified views, plus standard Git patch syntax symbols for code reviews and document redlining:

Diff Concept / Symbol	View Format	Meaning & Representation	Best Use Case
Split View (Side-by-Side)	Two Columns	Original text on the left, modified text on the right with synchronized scrolling.	Document proofreading, legal contracts, comparing two distinct article drafts.
Unified View (Inline)	Single Column	Combines deletions and additions into a single sequential timeline with color coding.	Source code reviews, software patches, Git commit inspections.
Minus Sign ( - )	Red Highlight / Strikethrough	Text or code lines present in the original version that have been removed or replaced.	Identifying deprecated code, deleted clauses, removed paragraphs.
Plus Sign ( + )	Green Highlight	New text or code lines inserted into the modified version.	Tracking newly introduced features, added contractual terms, updated copy.

Key Capabilities of Text Diff Checker

Split & Unified Views

View differences side-by-side or combined into a unified git-like diff stream.

Line-by-Line Alignment

Uses Longest Common Subsequence (LCS) algorithm for accurate text alignment.

Whitespace & Case Controls

Ignore accidental whitespace changes or enforce strict character comparison.

Instant Text Swap

Quickly invert original and modified texts with the one-click Swap button.

Frequently Asked Questions

Clear answers about using this tool and automating workflows with RunMacro.

Are my confidential documents or code uploaded to any server?

No. The diff computation runs 100% locally in your browser memory using JavaScript. No documents or code are ever sent to an external server.

What is the difference between Split and Unified view?

Split View displays the old and new text in two parallel columns. Unified View merges them into a single column with +/- prefixes, matching git diff formats.

Can I compare large files or scripts?

Yes. Our browser-based engine handles code files and text documents with thousands of lines smoothly and without lag.

How can RunMacro automate difference checks in business workflows?

RunMacro can automatically extract daily report exports, compare them against baseline spreadsheets, and highlight anomalies automatically.

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