Text Diff CheckerPrivate text and code comparison
en

AppHelp

Compare text and code side by side

Paste text or load two local files, then inspect additions and removals in split or unified views. Tune whitespace, case, blank-line, and context rules before exporting a standard patch.

Text comparison workspace

Paste or load two text files, inspect exact changes, and export a standard three-line-context patch.

Files stay in this browser

Original

original.ts

133 / 200,000

Changed

changed.ts

213 / 200,000
Highlight precision
Comparison rules
5Added lines
4Removed lines
3Unchanged lines
9Change total
original.ts
changed.ts
1
export function greet(name: string) {
1
export function greet(name: string, excited = false) {
2
  const message = `Hello, ${name}!`;
2
  const punctuation = excited ? "!" : ".";
3
  console.log(message);
3
  const message = `Hello, ${name}${punctuation}`;
4
  console.info(message);
4
  return message;
5
  return message;
5
}
6
}
6
7
7
greet("Ada");
8
greet("Ada", true);

Common tasks

  • diff checker
  • text compare online
  • text diff checker
  • compare two text files
  • code diff online
  • side by side diff
  • unified diff generator
  • word diff checker
  • character diff tool
  • free private diff checker

Quick answer

Paste two texts or load two local text/code files to compare them in the browser. AppHelp aligns changed lines, shows original and new line numbers, highlights entire lines or changed words/characters, can ignore whitespace, letter case, and blank lines, hides unchanged context on demand, and exports a conventional unified .diff patch with three context lines. Files are read locally and are not uploaded.

How to use

  1. 1. Provide the original and changed textPaste content into both editors or load local text, code, Markdown, JSON, CSV, log, XML, YAML, CSS, or HTML files.
  2. 2. Choose comparison precisionUse line precision for broad revisions, word precision for prose and code edits, or character precision for punctuation and identifier changes.
  3. 3. Tune ignore and context rulesIgnore whitespace, letter case, or blank lines only when those differences are irrelevant, and hide unchanged lines for a focused review.
  4. 4. Review and exportInspect both line numbers and summary counts, switch between split and unified views, then copy or download the three-context-line patch.

Examples

Code review

Input
console.log(message);
Output
console.info(message);

Whitespace-only edit

Input
const total = price + tax;
Output
const  total=price + tax;

Enable Ignore whitespace when formatting differences should not count.

Copy edit

Input
The report is ready for review.
Output
The quarterly report is ready for final review.

Common use cases

  • Review code, configuration, SQL, logs, and documentation changes
  • Compare generated output against an expected fixture
  • Inspect a contract, policy, resume, or article revision
  • Create a patch to share in an issue or code review
  • Check whether two files differ only in whitespace or letter case

Edge cases

  • This tool compares text; binary files, PDFs, Word documents, images, and spreadsheets need format-aware comparison.
  • Ignoring whitespace, case, or blank lines can hide meaningful changes in indentation-sensitive code, identifiers, credentials, or data.
  • Line-ending differences are normalized for the visual alignment, while the exported patch preserves the supplied text except for its explicit whitespace option.
  • Very large or highly divergent inputs can be expensive to align, so file size, text length, and live diff time are bounded.
  • The visual ignore-case and ignore-blank-line rules do not rewrite the exported patch; the patch remains suitable for reviewing original content.
  • A unified patch records textual changes but does not prove that the new code, configuration, or prose is correct.

Features

  • Private browser-local text and code comparison
  • Side-by-side split and compact unified diff views
  • Original and changed line numbers with addition and removal colors
  • Line, word, or character-level change highlighting
  • Whitespace, letter-case, blank-line, and unchanged-context controls
  • Addition, removal, unchanged-line, and total-change summaries
  • Local text-file loading plus paste and edit workflows
  • Copy or download a conventional unified .diff patch with three context lines

Related tools

JSON DiffCompare parsed JSON structures when key order and formatting should not dominate.Regex TesterBuild a pattern and compare text before and after replacement.Text CleanerNormalize common whitespace and line issues before comparison.

Frequently asked questions

Can I compare local files without uploading them?
Yes. The browser reads supported text files locally and performs alignment and highlighting without sending their contents to AppHelp.
What is the difference between split and unified views?
Split view aligns original and changed lines in two columns. Unified view places removals and additions in one review stream.
When should I use word or character precision?
Word precision is easier for prose and most code edits. Character precision reveals small punctuation, whitespace, spelling, and identifier changes.
What does Ignore whitespace do?
It treats line spacing differences as equivalent for alignment and suppresses whitespace-only intraline emphasis. Do not use it when indentation is meaningful.
Is the downloaded file a standard unified diff?
Yes. It includes original and changed filenames, hunk headers, plus/minus lines, and three unchanged context lines by default.
Why can the visual result differ from the patch?
Ignore case and blank-line options intentionally affect visual review only so the exported patch still records the original supplied text.
Are my texts or files uploaded?
No. File reading, comparison, highlighting, copying, and patch generation all happen locally in your browser.