Skip to content
Book a demoStart free

Text Comparison Tool (Diff Checker)

Compare two text blocks side-by-side with line-by-line diff highlighting of additions, deletions, and changes.

Text Comparison Tool (Diff Checker)GratisPopularContent SEORuns in your browser

Works in your browser. What you paste or upload is processed on your device.

Key features of the diff checker

  • Side-by-side text comparison with colour highlighting
  • Character-level, word-level, and line-level diff modes
  • Shows additions in green, deletions in red
  • Works with any text: articles, code, CSV data
  • Downloadable diff report

How to use the diff checker

  1. Paste original text

    Enter your original (before) text in the left panel.

  2. Paste new text

    Enter the updated (after) text in the right panel.

  3. Run the comparison

    Click 'Compare' to generate a diff showing all changes.

  4. Review changes

    Green highlights show additions; red shows deletions; unchanged text appears normally.

  5. Verify intended changes

    Confirm all changes are intentional and no content was accidentally removed.

What is a diff checker?

The Diff Checker compares two text inputs side by side, highlighting additions, deletions, and modifications between them. It's useful for comparing content versions, reviewing edits, checking changes between two drafts, and verifying that updated content differs meaningfully from the original.

In an SEO context, the diff checker is invaluable for content audits — comparing old and new page versions after updates, verifying that content migrations preserved all copy, or reviewing editorial changes before they go live.

Why use a diff checker?

When updating content at scale, it's easy to accidentally delete important sections, duplicate passages, or introduce errors during editing. A diff check between the old and new version catches these issues before publishing, ensuring every content update is intentional and error-free.

Diff checker: frequently asked questions

Something else? Ask the team

What is a diff checker?

A diff checker (short for 'difference checker') compares two text inputs and shows exactly what changed between them — additions, deletions, and modifications highlighted for easy review.

How is this useful for SEO?

For content migrations, updates, and audits: verify that page content transferred correctly, compare old vs. new meta tags, check that canonical or noindex tags weren't accidentally changed during CMS updates.

Can I compare code with this tool?

Yes. The diff checker works with any plain text, including HTML, CSS, JavaScript, and other code. It highlights syntax differences the same way it highlights content differences.

Is there a text length limit?

The tool handles typical article and page content lengths. Extremely large documents (100,000+ characters) may be slow to process. For very large comparisons, consider splitting into sections.

What are the different diff modes?

Line-level diff shows which lines changed. Word-level diff highlights individual changed words within lines. Character-level diff shows every character change, useful for catching single-letter errors.

Each one opens on its own page and works straight away, with no sign-up.

Explorar más herramientas gratuitas:Generador de SchemaGenerador de etiquetas MetaGenerador de LLMs.txtBrowse all free tools

¿Quieres conseguir más menciones en la IA?

Text Comparison Tool (Diff Checker) is one piece of the puzzle. See how ChatGPT, Gemini, Perplexity, and Google AI Overviews actually view your brand, and get a prioritised list of fixes, with a free AEO & GEO audit from AI Rank Lab.

One check is a start. The audit checks the whole site.

Realizar una auditoría AEO y GEO gratuita or Ver precios.

  • Scores SEO, answer-engine (AEO) and generative-engine (GEO) readiness
  • Lists the fixes, page by page
  • Then track whether ChatGPT, Gemini, Perplexity and Google AI Overviews cite you
fieldnote.app4,571 credits

Site audit

fieldnote.app · SEO, AEO and GEO

Illustrative data
SEO
82
+6
AEO
64
+11
GEO
58
+9
Pages
48
Fixesby impact
  • /pricing · Missing H1High
  • /blog/guide · No FAQ schemaMedium
  • /llms.txt · Not foundMedium
  • /about · Meta description too longLow

See where your whole site stands

Paste your site. The free audit scores it for SEO, answer engines and generative engines, with the fixes.

Start freeBook a demo