[opensourcedex]

changedetection.io is a free, open source data extraction & web scraping project written in Python and released under Apache-2.0. It has 34,295 GitHub stars, 2,063 forks and 385 open issues, and was last pushed 3 hours ago. On this registry it ranks #5 of 45 tracked projects in Data Extraction & Web Scraping, with 5 head-to-head comparisons available. It gained 86 stars over the last 3 tracked days.

What is changedetection.io?

What it is

changedetection.io is an open-source website change detection and web page monitoring tool written in Python and released under the Apache-2.0 license. It watches URLs, detects when their content changes, and sends alerts through channels such as Discord, Email, Slack, Telegram, and Webhook. The project lives in the Data & Analytics / Data Extraction & Web Scraping ecosystem, carries more than 34,000 stars and 2,000 forks on GitHub, and has been developed for roughly six years. It is designed to be self-hosted, and the same codebase also backs a hosted subscription service offered by the maintainers.

The concrete problem it solves is the manual, repetitive work of checking pages for updates. Instead of reloading a product page to see whether an item is back in stock, or re-reading a listing to catch a price drop, a user registers the URL once and lets the tool compare successive versions of the page. Detected differences are surfaced by word, line, or individual character, so the user sees exactly what moved. The project also targets website defacement monitoring and general content-edit tracking, and it publishes an RSS topic alongside its notification integrations.

Key capabilities

  • Change detection with diff output examined by word, line, or individual character.
  • Notification delivery to Discord, Email, Slack, Telegram, Webhook, and other integrations.
  • AI change detection rules that evaluate each diff against a plain-English intent and suppress irrelevant changes.
  • AI change summaries that replace raw diffs with plain-language descriptions of what changed.
  • Re-stock and price detection for single product pages, extracting product metadata from the HTML.
  • Price parameters including upper and lower price bounds and price change percentage.
  • Browser Steps for interactive sequences such as filling text boxes, clicking buttons, logging in, and accepting cookie prompts.

Who uses it and how

  • Shoppers monitoring product pages for restock alerts and price drops.
  • Teams watching documentation, listings, or content pages for edits and tracking changes over time.
  • Security-minded operators monitoring websites for defacement.
  • Users routing alerts into chat and automation systems through Discord, Slack, Telegram, and Webhook.
  • Operators running local models through Ollama, vLLM, LM Studio, or llama.cpp to keep AI evaluation on their own infrastructure.

Getting started

The README points to a Docker image, tracked by its Docker Pulls badge, as the standard self-hosted route. A hosted subscription at $8.99 per month is offered for users who prefer not to install anything and to access the service through a browser login.

When to use it — and when not to

The hosted plan is described as half the price of other website change monitoring services, which makes it a candidate replacement for paid monitoring products. A self-hoster must operate the instance and supply an LLM provider for the AI features, either a commercial API key or a self-hosted OpenAI-compatible endpoint. The Visual Selector tool and Browser Steps require Playwright to be enabled, and the Visual Selector is noted as available when connected to a Playwright content fetcher included with the subscription service.

project readme (upstream, from github) — read inline

Detect Website Changes Automatically — Monitor Web Page Changes in Real Time

Monitor websites for updates — get notified via Discord, Email, Slack, Telegram, Webhook and many more.

Detect web page content changes and get instant alerts.

Ideal for monitoring price changes, content edits, conditional changes and more.

Web site page change monitoring

[![Release Version][release-shield]][release-link] [![Docker Pulls][docker-pulls]][docker-link] ![License][license-shield]

changedetection.io

Get started with website page change monitoring straight away. Don't have time? Try our $8.99/month subscription, use our proxies and support! , half the price of other website change monitoring services!

  • Chrome browser included.
  • Nothing to install, access via browser login after signup.
  • Super fast, no registration needed setup.
  • Get started watching and receiving website change notifications straight away.
  • See our tutorials and how-to page for more inspiration

AI-powered website change detection — smart alerts and plain-language summaries

Stop drowning in noise. Connect any LLM (OpenAI, Gemini, Anthropic, Ollama and more) and go from "something changed" to "only the thing you care about changed".

AI change detection rules — write a plain-English intent once: "notify me only when the price drops below $50", "alert me when the item comes back in stock", "ignore navigation and footer changes". The AI evaluates every detected diff against your intent and silently suppresses everything irrelevant. Fewer false positives, zero noise.

AI change summaries — instead of staring at a raw diff, your notification reads "Price dropped from $89.99 to $67.00" or "3 new products added to the listing". Works globally or per-watch, with full control over the prompt.

Works with any model you already pay for — GPT-4o-mini and Gemini Flash handle this well at fractions of a cent per check. Or run it entirely locally with Ollama, vLLM, LM Studio, or any OpenAI-compatible self-hosted endpoint — pick the OpenAI-compatible (vLLM, LM Studio, llama.cpp) option in the provider dropdown and point it at your server's /v1 URL. Powered by LiteLLM, giving you seamless access to 100+ supported providers and models.

Note: Available in our subscription/hosted service from June 2026

Target specific parts of the webpage using the Visual Selector tool.

Available when connected to a playwright content fetcher (included as part of our subscription service)

Select parts and elements of a web page to monitor for changes

Easily see what changed, examine by word, line, or individual character.

Self-hosted web page change monitoring context difference

Perform interactive browser steps

Fill in text boxes, click buttons and more, setup your changedetection scenario.

Using the Browser Steps configuration, add basic steps before performing change detection, such as logging into websites, adding a product to a cart, accept cookie logins, entering dates and refining searches.

After Browser Steps have been run, then visit the Visual Selector tab to refine the content you're interested in. Requires Playwright to be enabled.

Awesome restock and price change notifications

Enable the "Re-stock & Price detection for single product pages" option to activate the best way to monitor product pricing, this will extract any meta-data in the HTML page and give you many options to follow the pricing of the product.

Easily organise and monitor prices for products from the dashboard, get alerts and notifications when the price of a product changes or comes back in stock again!

Set price change notification parameters, upper and lower price, price change percentage and more. Always know when a product for sale drops in price.

Example use cases

  • Products and services have a change in pricing
  • Out of stock notification and Back In stock notification
  • Monitor and track PDF file changes, know when a PDF file has text changes.
  • Governmental department updates (changes are often only on their websites)
  • New software releases, security advisories when you're not on their mailing list.
  • Festivals with changes
  • Discogs restock alerts and monitoring
  • Realestate listing changes
  • Know when your favourite whiskey is on sale, or other special deals are announced before anyone else
  • COVID related news from government websites
  • University/organisation news from their website
  • Detect and monitor changes in JSON API responses
  • JSON API monitoring and alerting
  • Changes in legal and other documents
  • Trigger API calls via notifications when text appears on a website
  • Glue together APIs using the JSON filter and JSON notifications
  • Create RSS feeds based on changes in web content
  • Monitor HTML source code for unexpected changes, strengthen your PCI compliance
  • You have a very sensitive list of URLs to watch and you do not want to use the paid alternatives. (Remember, you are the product)
  • Get notified when certain keywords appear in Twitter search results
  • Proactively search for jobs, get notified when companies update their careers page, search job portals for keywords.
  • Get alerts when new job positions are open on Bamboo HR and other job platforms
  • Website defacement monitoring
  • Pokémon Card Restock Tracker / Pokémon TCG Tracker
  • RegTech - stay ahead of regulatory changes, regulatory compliance

Need an actual Chrome runner with Javascript support? We support fetching via WebDriver and Playwright!

Key Features
  • Lots of trigger filters, such as "Trigger on text", "Remove text by selector", "Ignore text", "Extract text", also using regular-expressions!
  • Target elements with xPath 1 and xPath 2, CSS Selectors, Easily monitor complex JSON with JSONPath or jq
  • Switch between fast non-JS and Chrome JS based "fetchers"
  • Track changes in PDF files (Monitor text changed in the PDF, Also monitor PDF filesize and checksums)
  • Easily specify how often a site should be checked
  • Execute JS before extracting text (Good for logging in, see examples in the UI!)
  • Override Request Headers, Specify POST or GET and other methods
  • Use the "Visual Selector" to help target specific elements
  • Configurable proxy per watch
  • Send a screenshot with the notification when a change is detected in the web page

We recommend and use Bright Data global proxy services, Bright Data will match any first deposit up to $150 using our signup link.

Please :star: star :star: this project and help it grow! https://github.com/dgtlmoon/changedetection.io/

readme truncated — read the full docs on github

Frequently asked questions

Is changedetection.io free to use?

changedetection.io is open source under the Apache-2.0 licence. There is no licence fee and no seat count — you can self-host it or, where the project offers one, pay a vendor for a managed version instead.

What does changedetection.io do?

Best and simplest tool for website change detection, web page monitoring, and website change alerts. Perfect for tracking content changes, price drops, restock

What is changedetection.io written in?

changedetection.io is primarily written in Python. Its source is publicly available at https://github.com/dgtlmoon/changedetection.io, and it has 34,295 GitHub stars.