Webpage Diff Checker

Compare text content between two web page URLs and find differences.

What does Webpage Diff Checker do?

This actor compares text content between two web pages. It extracts visible text from both URLs, computes a line-by-line diff, and reports similarity percentage, added/removed lines, and a sample of differences. Useful for detecting content changes, comparing staging vs production, or A/B test validation.

You can compare multiple URL pairs in a single run. Each pair produces its own result with a similarity score, making it easy to identify which pages have changed and by how much.

Who is it for?

• 🔍 SEO specialists — detecting content changes on competitor pages and search results
• 💻 Web developers — verifying deployment changes by comparing page versions
• 📋 Compliance teams — monitoring regulatory pages for policy or terms updates
• 🛡️ Security analysts — detecting unauthorized modifications to web pages
• 📊 Market researchers — tracking product page changes and pricing updates

Use cases

• DevOps engineers -- compare staging vs production pages to verify deployments match before going live
• Content managers -- detect unauthorized or unexpected page changes across a website
• QA testers -- validate A/B test variants have the intended content differences
• Migration teams -- verify content is preserved correctly after a site migration or CMS switch
• Compliance officers -- monitor regulated pages (terms, privacy policy) for unauthorized edits
• SEO teams -- detect unexpected content changes that may affect search rankings or featured snippets

Why use Webpage Diff Checker?

• Batch comparison -- compare multiple URL pairs in a single run
• Similarity scoring -- get a percentage-based similarity score for quick assessment
• Line-level diffs -- see exactly which lines were added, removed, or changed
• Title matching -- separately checks whether page titles match
• Structured output -- machine-readable JSON with diff samples, ready for automated processing
• Pay-per-event pricing -- cost-effective for both one-off checks and regular monitoring
• Fast and lightweight -- HTTP-only requests with no browser overhead, so comparisons complete in seconds

Input parameters

Parameter	Type	Required	Default	Description
pairs	object[]	Yes	--	Array of URL pair objects, each with url1 and url2 properties

Each object in the pairs array must have:

Property	Type	Description
url1	string	First URL to compare
url2	string	Second URL to compare

Example input

{
    "pairs": [
        {
            "url1": "https://example.com",
            "url2": "https://www.example.com"
        }
    ]
}

Output example

{
    "url1": "https://example.com",
    "url2": "https://www.example.com",
    "isIdentical": true,
    "similarityPercent": 100,
    "titleMatch": true,
    "addedLines": 0,
    "removedLines": 0,
    "diffSample": [],
    "error": null,
    "checkedAt": "2026-03-01T12:00:00.000Z"
}

How to compare two web pages for differences

1. Open Webpage Diff Checker in Apify Console.
2. Add one or more URL pairs -- each pair has a url1 and url2 to compare.
3. Click Start to run the comparison.
4. View results in the Dataset tab -- each pair shows similarity percentage, added/removed lines, and a diff sample.
5. Download results as JSON, CSV, or Excel.

How much does it cost to compare web pages?

Event	Price	Description
Start	$0.035	One-time per run
Pair compared	$0.002	Per URL pair compared

Example costs:

• 5 pairs: $0.035 + 5 x $0.002 = $0.045
• 50 pairs: $0.035 + 50 x $0.002 = $0.135
• 500 pairs: $0.035 + 500 x $0.002 = $1.035

Using the Apify API

Node.js

import { ApifyClient } from 'apify-client';

const client = new ApifyClient({ token: 'YOUR_TOKEN' });
const run = await client.actor('automation-lab/webpage-diff-checker').call({
    pairs: [{ url1: 'https://example.com', url2: 'https://www.example.com' }],
});
const { items } = await client.dataset(run.defaultDatasetId).listItems();
console.log(items);

Python

from apify_client import ApifyClient

client = ApifyClient('YOUR_TOKEN')
run = client.actor('automation-lab/webpage-diff-checker').call(run_input={
    'pairs': [{'url1': 'https://example.com', 'url2': 'https://www.example.com'}],
})
items = client.dataset(run['defaultDatasetId']).list_items().items
for item in items:
    print(f'Similarity: {item["similarityPercent"]}%')

cURL

curl -X POST "https://api.apify.com/v2/acts/automation-lab~webpage-diff-checker/runs?token=YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "pairs": [{"url1": "https://example.com", "url2": "https://www.example.com"}]
  }'

Use with Claude AI (MCP)

This actor is available as a tool in Claude AI through the Model Context Protocol (MCP). Add it to Claude Desktop, Cursor, Windsurf, or any MCP-compatible client.

Setup for Claude Code

$claude mcp add --transport http apify "https://mcp.apify.com"

Setup for Claude Desktop, Cursor, or VS Code

Add this to your MCP config file:

{
    "mcpServers": {
        "apify": {
            "url": "https://mcp.apify.com"
        }
    }
}

Example prompts

• "Compare these two web pages for differences: example.com and www.example.com"
• "Show what changed between the staging and production version of this page"
• "Are these two product pages identical in content?"

Learn more in the Apify MCP documentation.

Integrations

Webpage Diff Checker integrates with your existing workflow through the Apify platform. Connect it to Make (formerly Integromat), Zapier, or n8n to schedule regular comparisons and trigger alerts when differences are detected. Send notifications to Slack when pages diverge, log comparison results in Google Sheets for audit trails, or use webhooks to integrate diff checks into your CI/CD pipeline.

Common integration patterns include:

• Deployment verification -- trigger a comparison after each deployment via webhook, comparing staging and production URLs automatically
• Content monitoring -- schedule daily runs to detect changes to pricing pages, terms of service, or other regulated content
• Audit logging -- push every comparison result to Google Sheets or a database to maintain a historical record of content changes

Tips and best practices

• Schedule daily or weekly runs to monitor important pages for unexpected changes, such as pricing pages or legal documents.
• Compare staging and production URLs before every deployment to catch content discrepancies early.
• Check the diffSample field for a quick preview of what changed without downloading the full dataset.
• Use similarity percentage thresholds in your automation to only trigger alerts when changes exceed a certain amount (e.g., less than 95% similarity).
• Pair with webhooks to build a content change monitoring system that alerts your team in real time.

Legality

This tool analyzes publicly accessible web content. Automated analysis of public web resources is standard practice in SEO and web development. Always respect robots.txt directives and rate limits when analyzing third-party websites. For personal data processing, ensure compliance with applicable privacy regulations.

FAQ

Does it compare HTML or text? It compares visible text content extracted from the pages, not raw HTML. This gives a more meaningful comparison focused on what users actually see, ignoring markup differences that do not affect the displayed content.

Can I compare more than two pages at once? Yes. The pairs input accepts an array, so you can compare multiple URL pairs in a single run. Each pair produces its own result in the output dataset.

Does it handle dynamic content? The actor fetches pages via HTTP without a browser. Content that requires JavaScript rendering may not be captured. For most server-rendered pages, the comparison works well.

What does the diffSample field contain? The diffSample field contains a preview of the actual differences found between the two pages. Each entry shows the type of change (added or removed) and the affected text, giving you a quick summary without needing to compare the pages manually.

Can I use this for regression testing? Yes. Many teams use Webpage Diff Checker as part of their deployment pipeline to compare staging and production content. Pair it with scheduled runs or webhooks to automate regression detection after every release.

What does 100% similarity mean? A similarity of 100% means the visible text content of both pages is identical. The pages may still differ in HTML structure, styling, or scripts, but the text a user would see is the same.

Can I compare pages from different websites? Yes. The two URLs in each pair can be from different domains. This is useful for comparing mirrored content, syndicated articles, or localized versions of the same page.

The comparison shows differences even though the pages look identical in a browser. Why? The actor compares the raw text content from the initial HTTP response. Dynamic content like timestamps, session-specific elements, personalized content, or A/B test variations can cause differences even when the core content is the same. If you see many small differences from dynamic elements, consider using Website Change Monitor instead, which supports ignore patterns for filtering noise.

One or both URLs return an error. How do I troubleshoot? Check that both URLs are publicly accessible and return HTML content. Pages behind authentication, bot protection (like Cloudflare challenges), or that require JavaScript rendering may fail. The error field will contain the specific failure reason for each URL in the pair.

Other SEO tools

• Wayback Machine Checker -- check Internet Archive snapshot history for any URL
• Website Change Monitor -- monitor websites for content changes over time
• Broken Link Checker -- find broken links on any website
• Redirect Chain Analyzer -- trace HTTP redirect chains and detect issues