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Website change detection that catches the change the minute it happens

Point MonitoringDaddy at any public web page, tell it which text matters, and get a web page change alert the moment that text appears or disappears — while your competitor's price drop, a silent policy edit or a defaced page is still news.

Free for your first page — no credit card. You pick exactly what to watch in the next step.

  1. 1Paste the page
  2. 2Click the part that matters
  3. 3Get emailed when it changes

Free plan forever · No credit card · First monitor live in under a minute

What is website change detection?

Website change detection is the automated monitoring of a web page for changes to its content. A change monitor re-fetches the page on a fixed interval, compares what it finds against a condition you define, and sends a notification when the page no longer matches. MonitoringDaddy offers two ways to do it. Keyword conditions alert when a phrase you name appears or disappears. Full content change detection captures the whole page on every check and alerts you when anything meaningful changes — showing exactly which words were added or removed, with a version history you can scroll back through.

Manually reloading a page to see whether anything moved does not scale past one page and one person. A website change monitor removes the human polling loop entirely: the check runs on a schedule from external infrastructure, so it sees exactly what a real visitor sees, and the notification arrives wherever your team already works. Used this way, a website change checker is less a research tool than a standing alarm — you set it once and forget it until it has something to tell you.

Webpage change detection and website change detection describe the same job, and people search for both — the only real distinction is scope. A single URL is what a monitor watches; "site-wide" coverage just means pointing one monitor at each page that matters to you.

Because checks run from outside your network, the same monitor that performs change detection also confirms the page is reachable at all. Pair it with website uptime monitoring for the complete picture: is the page up, and is it still saying the right thing?

How it works

Two conditions cover almost every page change worth knowing about

Rather than diffing an entire page and drowning you in cosmetic noise, MonitoringDaddy asks you to declare the signal. That single decision is what makes web page change monitoring quiet enough to actually leave switched on.

Alert when text disappears

Choose "URL response does not contain text" and name a phrase that should always be present. You are notified the moment it is gone — a product going out of stock, a price changing, a trust badge vanishing, a page being replaced or defaced.

Condition: URL response does not contain text Text: In Stock Fires when: the phrase is no longer on the page Result: alerted the second the product stops showing "In Stock"

Alert when text appears

Choose "URL response contains text" to be told when something new shows up on a page that did not have it before — a back-in-stock button, a new job posting, a status banner, a competitor's launch announcement.

Condition: URL response contains text Text: Add to Cart Fires when: the phrase appears on the page Result: alerted the second a sold-out product becomes purchasable

Check intervals from 60 seconds to hourly

Every monitor has its own interval, so a competitor's blog index can be checked hourly while a limited-release product page is checked every minute. Faster intervals detect a web page change sooner, at the cost of more requests against the target page — pick the slowest interval that still gets you the answer in time.

Alerts land where your team already is

A single monitor can carry several alert channels at once, so one webpage change notification reaches an inbox, a chat channel and an internal webhook simultaneously.

ChannelTypical use
EmailThe default. Available on every plan, including free.
SlackRoute change alerts into the channel that owns the page.
Microsoft TeamsSame, for Teams-based organisations.
DiscordPopular for community, restock and deal-watching alerts.
TelegramFast personal notifications on mobile.
FlockIncoming-webhook delivery for Flock workspaces.
WebhookPOST the event into your own system — ticketing, scraping pipeline, internal bot.
SMSAvailable when SMS delivery is enabled on the installation.
Setup

How to set up a web page change alert in four steps

About two minutes, start to finish. No script to write, nothing to install.

1

Add the page

Create a monitor and paste the full URL of the page you want to detect changes on. Give it a name you will recognise in an alert at 3 a.m.

2

Pick the condition

Choose "URL response contains text" to catch an appearance, or "URL response does not contain text" to catch a disappearance.

3

Set text and interval

Enter the exact phrase to watch, then choose how often the page is fetched — from every 60 seconds up to hourly.

4

Add alert channels

Attach email, Slack, Teams, Discord, Telegram or a webhook and save. Checking starts immediately and runs until you pause it.

Choosing the right text is the whole game. Pick something short, distinctive and stable — the phrase a human would look for to answer "did the thing I care about change?". A full paragraph, a timestamp, a view counter or a rotating banner will alert on every check. For a longer walkthrough see the keyword monitoring setup guide.

Use cases

What people actually monitor website changes for

Every one of these is the same two conditions pointed at a different page — whether you want to track webpage changes on a supplier's catalogue or simply detect a web page change on your own checkout before a customer does. The skill is in choosing the phrase.

Use caseWhat to watchCondition to use
Back-in-stock alerts Product, ticket or release pages Alert when Add to Cart appears
Price change tracking Competitor and supplier product pages Alert when the current price string disappears — see price monitoring
Competitor content monitoring Homepages, blog indexes, press-release archives, changelogs Alert when a new headline or version string appears
Policy and terms changes Supplier terms, regulator notices, licence pages Alert when the current effective-date string disappears
Defacement and tamper detection Your own homepage, checkout and landing pages Alert when your brand or trust phrase disappears
Deployment verification Any page that renders a build or version number Alert when the new version string appears
Job posting watches Careers pages at target companies Alert when a role title appears
Broken-integration detection Pages whose content depends on a third-party feed or widget Alert when expected feed content disappears
SEO regression watch Money pages after a CMS or theme update Alert when a key H1 or product name disappears
Grant, tender and admission notices Government and university notice boards Alert when a keyword such as Applications open appears
60s
Fastest check interval
8
Alert channels
24/7
Unattended checking
$0
To start, permanently
Plans

What website change monitoring costs

Free website change detection is a real, permanent tier here, not a 14-day trial that turns into an invoice. Change-detection monitors share the same allowance as uptime, SSL and domain monitors — mix them however you need inside your plan.

PlanMonitorsFastest intervalAlert channelsAPIPrice
Free1Every 30 minutesEmail$0
Basic10Every 10 minutesEmail + webhook & chatYes$8/mo
Growth50Every 5 minutesEmail + webhook & chatYes$19/mo
Pro100Every 60 secondsEmail + webhook & chatYes$34/mo

Annual billing is cheaper on every paid tier. Plan contents can change — the pricing page is the authoritative list.

Honest limits

What this change detector will not do

Worth knowing before you set up ten monitors and wonder why two of them are silent.

MonitoringDaddy fetches the raw HTML response of a URL and matches text against it. That makes it fast, cheap to run at short intervals, and precise — but it also means the following cases are out of scope.

  • JavaScript-rendered content. If the text is injected client-side after load, it is not in the response and cannot be matched. Monitoring the underlying API endpoint usually works instead.
  • Visual and layout diffs. There is no screenshot comparison. A page can be visually redesigned without any monitored phrase changing.
  • Interactive logins. HTTP basic auth and static request headers are supported; session-based, CSRF-protected or MFA logins are not.
  • Aggressive bot protection. Sites fronted by strict challenge pages may block automated checks entirely, or serve the challenge page instead of the real content.
  • Unlimited version history. Versions are retained per monitor up to a rolling limit, not forever. Older captures are pruned as new ones arrive.

If any of those are hard requirements, a rendering-based visual diff tool is the right choice and we would rather say so here than after you have signed up. For everything else — and that is most store pages, news pages, docs, notice boards and server-rendered marketing sites — text-condition change detection is both more precise and far quieter.

Best practice

Five habits that keep change alerts trustworthy

1. Watch the smallest phrase that carries the meaning

Add to Cart beats an entire product description. Short strings survive unrelated copy edits; long ones break constantly and train your team to ignore the alerts.

2. Never match on anything that changes by itself

Timestamps, cart counts, CSRF tokens, "12 people are viewing this", rotating testimonials and randomised ad slots all change on every request. Matching them guarantees a permanent alert storm.

3. Match the interval to the consequence

A limited-drop product page justifies 60-second checks. A supplier's terms page does not — hourly is plenty, and it is politer to the site you are checking.

4. Run change detection alongside uptime, SSL and domain checks

A page that returns HTTP 200 with the wrong content, an expired SSL certificate, or a lapsed domain are three different failures with three different fixes. Cover all of them or you will find out about the gap the hard way.

5. Send the alert where someone will actually see it

A change alert in an unread inbox is not monitoring. Route it into the chat channel that owns the page, and put customer-visible incidents on a hosted status page so people stop asking.

For developers

Website change detection API

Change-detection monitors are ordinary monitors, so everything on this page is scriptable through the REST API on plans that include API access. Create a monitor per URL from a list, sync conditions from your own database, or tear monitors down when a campaign ends — without touching the dashboard.

Full request and response detail lives in the monitors API reference. If you want to monitor an API endpoint rather than manage monitors through one, the REST API monitoring guide covers that case, and the SSL monitoring API covers certificate checks.

Guides

What people actually watch

The technique is the same every time; the judgement about what to select and how often to check is not. Each guide covers one job, including the cases where this approach will not work.

SSL certificate expired

Reissue the certificate, deploy it to every server that terminates TLS, restart or reload the web server, and then verify from outside your own networ...

Domain expired

Almost certainly, if you act quickly.

How often to check uptime

Five minutes is right for most sites and is what we default to.

Why alerts get ignored

Make every alert mean something.

Best domain expiry monitoring tools

For most people the right answer is whatever already monitors the site, because domain expiry should not need its own subscription.

Best hosted status page tools

It depends on whether the page should update itself.

Best SSL monitoring tools

It depends on what you are protecting against.

Best uptime monitoring tools

For a personal project, UptimeRobot's free plan with 50 monitors is unbeatable — provided the site is genuinely non-commercial, which its licence now...

Best website monitoring tools

There is no single answer, because the tools are built around different failure modes.

Competitor price monitoring

Point a change detector at the competitor's pricing page, select the region that holds the price rather than the whole page, and choose how often to c...

RFP and tender monitoring

Point a change detector at the portal's search-results or listing page — the one showing current opportunities filtered to your categories — and selec...

Regulatory change monitoring

Point a change detector at the regulator's guidance or rule page and select the body text.

Competitor website monitoring

Pick the handful of pages that carry signal — pricing, product, careers, customers, changelog — and watch each one for text changes.

Terms and policy monitoring

Watch the supplier's published terms, privacy policy, DPA and subprocessor list for text changes.

Website defacement monitoring

Watch your own pages the way you would watch a competitor's.

SEO change monitoring

Watch your money pages and your critical files for text changes.

Job posting monitoring

Watch the company's own careers page rather than a job board.

For journalists

Watch the specific pages that matter — a department's guidance, a company's statement, a candidate's policy page — and get alerted the same day the wo...

For ecommerce

Three things.

For finance

To shorten the gap between a company publishing something and you knowing about it.

For SaaS

Four things, and most small teams only cover the first.

For agencies

One monitor per client site for outages, certificate and domain expiry warnings attached to each, and a content watch on any client who edits their ow...

Price drop monitoring

Point a change detector at the product page, select the region containing the price, and choose how often to check.

Back-in-stock alerts

Watch the product page and select the region that shows availability — the "out of stock" label, the add-to-basket button, or the size selector.

Ticket availability

Watch the event page and select whatever indicates availability — a "sold out" label, the ticket type list, or the checkout button.

Appointment availability

Watch the booking page and select the calendar or slot list.

MAP monitoring

Watch each reseller's listing page for your products and select the price region.

See it

What an alert actually looks like

Every recorded change is compared word by word and kept with a before-and-after image. This is the real output, shown with worked example data.

competitor.com/pricing Watching: Pricing table
Pro plan — $49 per month
+ Pro plan — $39 per month
+ Save 20% with annual billing

Price fell from $49 to $39, and an annual discount was added.

2 words added · 1 removed · 4.1% of the watched region

retailer.com/product/… Watching: Availability
Out of stock
+ In stock — ships tomorrow
+ Add to basket

The item is available again and the basket button returned.

6 words added · 3 removed · 12.5% of the watched region

supplier.com/subprocessors Watching: Subprocessor list
~ Data is processed in the EUthe EU and the United States
+ Added: Northwind Analytics Inc. (United States)

A new subprocessor was added in another jurisdiction.

9 words added · 2 removed · 1.8% of the watched region

Worked example — not live data. Start monitoring free
Alerts

Where we can reach you

The free plan sends to one email address. Every paid plan adds the chat and webhook channels below, with 2 to 10 destinations depending on the plan. However many alerts you receive, the price does not change — nothing here is metered or charged per alert.

Email Before and after images inline
Browser push On a phone or desktop lock screen
RSS feed Every recorded change, as a feed
SlackPaid Through an incoming webhook
Microsoft TeamsPaid Through an incoming webhook
DiscordPaid Through an incoming webhook
TelegramPaid Straight to a chat or channel
FlockPaid Through an incoming webhook
WebhooksPaid Post to anything you run yourself

There are no voice calls and no SMS. If a phone call at 3am is a hard requirement, say so before you subscribe — we would rather tell you now than refund you later.

FAQ

Website change detection questions, answered

What is website change detection?

Website change detection is an automated process that re-fetches a web page on a schedule and notifies you when its content no longer matches what you expect. Instead of manually reloading a page to see if something changed, a website change monitor does the checking for you and sends a web page change alert the moment the condition you defined is met.

How do I get an alert when a web page changes?

Add the URL as a monitor, choose the alert condition ("URL response contains text" or "URL response does not contain text"), enter the text to watch for, pick a check interval, and add one or more alert channels. From then on MonitoringDaddy will notify you when a web page changes in the way you described — no manual checking required.

Can I monitor a website for changes for free?

Yes. The free plan includes 1 monitor with 30-minute checks and email alerts, with no credit card required and no trial expiry. Unlike tools that meter you by the check, those 30-minute checks are unlimited — that is roughly 4,300 checks a month, where a metered competitor's free tier gives you about 150. Paid plans start at $5/month.

How often does MonitoringDaddy check for webpage changes?

Check intervals range from every 60 seconds to every hour, depending on your plan. The free plan checks every 30 minutes; Founding Member and Growth check every 5 minutes, Basic every 10 minutes, and Pro every 60 seconds. Faster intervals mean you find out about a change sooner, but also generate more requests against the page you are watching.

Where do change notifications get delivered?

Change alerts can be sent to email, Slack, Microsoft Teams, Discord, Telegram, Flock, and generic webhooks — and to SMS when SMS is enabled on the installation. You can attach several channels to a single monitor, so a webpage change notification can reach both an inbox and a team chat at the same time.

Does website change detection work on JavaScript-rendered pages?

Not reliably. MonitoringDaddy fetches the raw HTML response of the URL, so it detects changes in server-rendered markup. If the text you want to watch is injected by client-side JavaScript after page load, it will not appear in the response and cannot be matched. Many single-page applications expose the same data through an API endpoint — monitoring that URL instead usually works well.

Can I track price changes on a competitor product page?

Yes, within the limits of text matching. Watch for the exact price string (for example $49.00) using the "does not contain text" condition — you get a web page change notification as soon as that price is no longer on the page, which is exactly the moment it changed. See the price monitoring guide for the full walkthrough.

Can I use it for back-in-stock alerts?

Yes, and it is one of the most popular uses. Set the condition to "URL response contains text" and watch for a phrase that only appears when the item is purchasable, such as "Add to Cart". You are notified the moment the sold-out product becomes available again.

Is there a website change detection API?

Yes. Monitors — including change-detection monitors — can be created, read, updated and deleted through the REST API on plans that include API access. See the monitors API reference to script bulk creation of change monitors, or the REST API monitoring guide to monitor an API endpoint itself.

How is change detection different from uptime monitoring?

Uptime monitoring answers "is the page up?" — it alerts when a URL becomes unavailable or returns an error. Change detection answers "is the page still saying what it should?" — the page can return a perfect HTTP 200 while its content is wrong, defaced, or silently updated. Most teams run both conditions on their critical pages. See the uptime monitoring guide.

Can I monitor pages behind a login?

Only when the page is reachable with HTTP basic authentication or a static request header, both of which a monitor can send. Pages that require an interactive session, a CSRF token or multi-factor login cannot be checked, and pages behind aggressive bot protection may block automated requests.

How do I avoid false alerts from dynamic content?

Pick a keyword that is stable when nothing meaningful has changed. Avoid timestamps, view counters, session IDs, rotating banners and CSRF tokens — they change on every request and will alert constantly. A short, distinctive phrase from the part of the page you actually care about produces far cleaner alerting than a long block of text.

How many web pages can I monitor for changes?

One on the free plan, 25 on Founding Member, 10 on Basic, 50 on Growth and 100 on Pro. Change-detection monitors draw from the same monitor allowance as uptime, SSL and domain monitors, so you can mix monitor types however you like within your plan limit.

How does this compare to visual change detection tools?

Tools in the visual-diff category — Visualping, Wachete, changedetection.io, Follow That Page and similar — render the page in a browser and highlight what moved on screen, which is useful for design and layout review. MonitoringDaddy diffs the page content rather than its pixels: it captures the readable text on every check, shows you word-by-word what was added and removed, and keeps a version history — with CSS selectors and ignore rules to strip out banners, adverts and counters. If you need a screenshot comparison or the page only renders its content in JavaScript, a visual tool is the better fit. If you want precise, low-noise change alerts in the same dashboard as your uptime and SSL monitoring, this is.

Can I get an SMS or Slack alert when a page changes?

Slack, Teams, Discord, Telegram and Flock alerts are available on any plan that includes webhook alert channels. SMS alerts are only available when the installation has SMS delivery configured — check the pricing page for what your plan includes.

AG
Written by

Amit Gupta

Amit Gupta is the founder of MonitoringDaddy | Uptime, SSL, Domain, API & Cron Monitoring, a website and infrastructure monitoring platform built by TotosLocal One Private Limited. He writes about uptime, change detection, SSL and domain monitoring, and helps teams keep their websites fast, secure and online.

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