HOURLY
Competitor pricing pages
Price, promo badge, shipping threshold, stock. The value of the alert decays fast: knowing on Friday that a rival cut prices on Monday is trivia. Knowing within the hour is a decision.
Website Change Monitoring Down to a Single Field
Website change monitoring means re-reading a page on a schedule and telling you when something you care about is different. WebRobot watches fields, not pixels: you name the price, the stock status, the job title or the clause, and the robot alerts Slack, email or a webhook the moment that value moves. A rotating hero banner will not wake anyone up. A competitor cutting a price by 20 percent will.
Last updated July 2026
Robot console · WR-01
Standing by Running · s Complete · rows
1 · Pick a target
3 · Fields to extract
Agent log
Crawl graph
Extracted data · rows
Want this data fresh every morning, without lifting a finger?
01 / DETECTION
FIG. 1 · WHAT COUNTS AS A CHANGE
Three ways to detect a webpage change, and what each one costs you
Every monitoring tool answers the same question differently: what is a change? The answer decides how
many useless alerts you get on a Tuesday afternoon.
| Method | What it compares | Fires on | Fails when |
|---|---|---|---|
| Visual diff | Screenshots, pixel regions | Any visible movement in the region | Carousels, ads, cookie banners, A/B tests |
| Text or HTML diff | The raw page source or the text blob | Any character difference | Timestamps, session IDs, view counters |
| Field-level | Named values: price, stock, title, date, clause | Only the value you asked about | Rarely: intent survives redesigns |
Visual and text diff tools are genuinely useful, cheap and often free, and if you are watching one public page for "did anything at all happen", they are the right pick. They fall apart at scale. Watch 40 competitor product pages with a pixel diff and you will get several hundred alerts a week, almost all of them a rotating promo image. The team stops reading them by Thursday, which means the one alert that mattered gets ignored too.
Field-level monitoring inverts that. The robot extracts the same structured row every run ("SKU, price, promo flag, stock"), diffs the row against the last one, and only fires when a named field is different. The alert carries the old value and the new one, so it is readable without opening the page.
02 / SETUP
FIG. 2 · FIVE STEPS
How to monitor a website for changes in five steps
Worked example: a pricing analyst who needs to know within the hour when any of four competitors changes
a price on their top 200 SKUs.
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01
Give the robot the pages
Paste a list of URLs, or point the robot at a category page and let it paginate to find the products itself. One robot can hold the whole watch list. If the pages sit behind a partner login, store the credentials once and the agent signs in on every check.
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02
Name the fields that count as a change
"Price, promo badge, stock status." Everything else on the page is explicitly not a change: the reviews counter can tick, the banner can rotate, the "12 people are viewing this" widget can do whatever it likes. Nothing fires.
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03
Set the check frequency
Daily on Launch, hourly with change alerts on Scale, real-time monitors on Autopilot. Frequency should track how fast the value moves and how much a late answer costs you. Hourly is the right default for competitor pricing.
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04
Add a threshold so the alert is worth reading
Alert on any stock flip, but only on price moves above two percent. Ignore currency rounding. Batch low-priority changes into one digest and send the urgent ones on their own. This is the step that decides whether the channel survives its first month.
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05
Route it to where the decision gets made
Slack for the analyst who reprices, a webhook into the pricing engine for automatic response, Google Sheets for the running history, the REST API for the warehouse. Alerts that land in an inbox nobody owns are the same as no alerts.
The full walkthrough for the pricing case is in how to monitor competitor prices, and the dedicated price monitoring tool page covers repricing workflows in more depth.
03 / TARGETS
FIG. 3 · PAGES WORTH WATCHING
What to track changes on, and how fast
Not every page deserves a monitor. These five do, and the cadence is different for each.
HOURLY
Job boards and careers pages
New postings are a hiring signal and a sales signal. Watch title, team, location and posted date. A company opening six infrastructure roles is telling you something about its roadmap.
REAL TIME
Inventory and restock
Stock flags, allocation windows, ticket availability. This is the one case where minutes matter and a daily check is worthless. Real-time monitors are on the Autopilot plan.
DAILY
Legal, policy and terms pages
A supplier quietly editing a liability clause or a platform changing its API terms. Watch the clause text and keep the previous version, so legal can see exactly which sentence moved.
DAILY
Regulatory and public filings
Agency notice boards, tender lists, license registers. Mostly quiet, occasionally decisive, and almost never equipped with an RSS feed or an API.
DAILY
Competitor product and pricing copy
Plan names, feature lists, tier limits. Positioning changes show up here weeks before anyone announces them. Pair it with a data extraction tool run to keep the full history.
04 / ALERTS
FIG. 4 · ALERT ROUTING
What a useful website change alert contains
An alert that says "this page changed" makes a human open the page and hunt. An alert that says what
changed makes a decision possible from a phone.
| Channel | Carries | Best for | Plan |
|---|---|---|---|
| Slack message | Field name, old value, new value, URL, timestamp | Analysts and buyers who act same day | Scale and up |
| Email digest | Batched list of changed rows | Legal and policy watching | All plans |
| Webhook | JSON payload with the diff | Automatic repricing or ticket creation | Scale and up |
| Zapier | Trigger with the changed row | Routing into Asana, Jira, HubSpot | Scale and up |
| Google Sheets row | Append-only change history | Trend charts and audit trail | All plans |
| REST API | Latest dataset and per-run diffs | Feeding a warehouse or dashboard | All plans |
Change alerts and hourly checks begin on Scale at $249 per month ($199 billed yearly), which also includes agent actions, so monitored pages can sit behind a login. Launch at $79 covers daily checks on 5 robots and 10,000 records. Autopilot at $699 adds real-time monitors and 1,000,000 records. See pricing for the full breakdown, and security for how stored credentials are handled.
05 / RELIABILITY
FIG. 5 · SILENT FAILURE
The failure mode nobody notices: the monitor that stopped watching
A broken scraper is loud. A broken monitor is silent, because "no change detected" and "I can no longer
find the field" look identical from the outside.
The redesign
A selector-based monitor points at a CSS path. The site renames the class, the path resolves to nothing, and the monitor reports calm forever. WebRobot stores the intent ("the price next to the buy button") and re-locates the field after a layout change, then notes the repair in the run log.
The alert nobody reads
Noise is the other silent failure. If the channel fires 200 times a week, it is functionally off. Thresholds, field scoping and digests are not conveniences, they are what keeps the signal credible.
The page that stopped loading
A login expiring, a region block, a page moved to a new URL. Runs record status and row counts, so a run that returns zero rows where it returned 200 yesterday is reported as a failure, not as "no changes". More on run mechanics in how it works.
06 / FAQ
FIG. 6 · FIELD QUESTIONS
Website change monitoring questions people actually ask
Point a monitor at the page, name the fields that matter (price, stock, posting date, clause text),
pick a check frequency, and choose where alerts land. WebRobot re-reads the page on that schedule,
compares each field to the last run, and notifies you only when a named field moves.
Route alerts to Slack, email, a webhook or Zapier. WebRobot sends the old value, the new value, the
field name, the page URL and a timestamp, so the alert is actionable on its own. Hourly checks and
change alerts start on the Scale plan at $249 per month.
The best tool depends on what you are watching. Visual diff tools are fine for "did anything move on
this page". If you need to know that one competitor SKU dropped from $249 to $199 while the rest of
the page churned, you need field-level monitoring, which is what WebRobot does.
Yes. Browser extensions and open source projects such as self-hosted change detectors monitor pages
at no cost, and they work well for a handful of simple public URLs. WebRobot has no free tier. It
starts at $79 per month and is built for many pages, logins and structured fields.
Watch fields, not pixels. A visual diff fires on every rotating banner and cookie notice.
Field-level monitoring only fires when the value you named changes, and you can set thresholds, for
example alert only when a price moves more than two percent.
Yes. The agent signs in with credentials you store, navigates to the page and reads the fields, so
supplier portals, seller dashboards and partner price lists can be monitored like public pages.
Logins and multi-step agent actions are included on Scale and Autopilot.
Match the check to how fast the value moves. Legal and policy pages are fine daily. Competitor
pricing and job boards usually warrant hourly. Inventory, ticket and restock pages need real-time
monitors, which are on the Autopilot plan at $699 per month.
Yes. One robot can watch a whole list of URLs, and each URL is compared field by field against its
own previous run. Plans allow 5 robots on Launch, 25 on Scale and 100 on Autopilot, with 10,000 to
1,000,000 records per month. The web
scraping tool overview explains how a single robot covers a list of pages.
FINAL ASSEMBLY
Know the minute the number changes
Name the field, set the cadence, pick the channel. The robot watches the page and only speaks when it matters.