Five tools, their own published numbers, and the arithmetic nobody prints: how many days one page actually gets before the allowance runs out.
Most lists of website change detection tools compare the check interval, which is the number that matters least. The one that stops you is the monthly check allowance. Visualping's free plan lets you set a 60-minute interval and includes 150 checks, so a single page runs out in about six days. Every figure on this page came from the tools' own pricing pages, read on 9 September 2026.
Three numbers decide it: how many pages you may watch, how often you may check them, and how many checks you get. The third is usually printed smallest. A 30-day month holds 720 hours, so one page checked hourly costs 720 checks. Set that against what each free plan includes and the picture changes.
| Tool | Pages | Checks a month | Fastest interval | One page at that interval |
|---|---|---|---|---|
| Visualping Free | 5 | 150 | 60 minutes | Runs out in about 6 days |
| PageCrawl Free Forever | 6 | 220 | 60 minutes | Runs out in about 9 days |
| Distill Free | 5 in the cloud, 25 locally | 1,000 in the cloud | 6 hours | Lasts the month |
| changedetection.io self-hosted | Your server decides | No plan, so no quota | Your server decides | Lasts the month |
| StockWatch Free | five monitors free | No quota | 60 seconds | Lasts the month |
Visualping does not hide the consequence. Its pricing page says that if you run out of checks, "monitoring pauses until your monthly allowance resets or you move to a larger plan", and answers the obvious follow-up with "No, checks do not roll-over monthly". Spread 150 checks across the 5 pages the plan allows and each page gets 30 a month, or one look a day.
Distill is the interesting one here, because its free tier fails in the other direction. Five cloud monitors at a six-hour floor use 4 checks a day each, so 600 of the 1,000 checks over a month. The quota is generous. The floor is the problem, and six hours is no use for anything that sells out. Distill also caps free email alerts at 30 a month, which is worth knowing before you point it at something busy. We went through the rest of its limits in our Distill.io alternative write-up.
Work each paid plan out at its own advertised fastest interval and the value gap is large. One page needs 2,880 checks a month at 15 minutes, 4,320 at 10 minutes and 8,640 at 5 minutes. Divide the included allowance by that and you get the number the price list does not print: how many pages the plan can genuinely run flat out.
| Plan | Price a month | Checks included | Fastest interval | Pages it runs all month |
|---|---|---|---|---|
| changedetection.io hosted | $8.99 | No published quota | About 5 minutes | Up to 5,000 URLs |
| PageCrawl Standard | $13.33, billed $160 a year | From 15,000 | 15 minutes | 5 on the entry allowance |
| Visualping Personal 1K | $14 | 1,000 | 15 minutes | Not even one |
| Distill Starter | $15 | 30,000 | 10 minutes | 6 |
| Distill Professional | $35 | 100,000 | 5 minutes | 11 |
| Visualping Personal 5K | $35 | 5,000 | 5 minutes | Not even one |
The two $35 rows are the ones to sit side by side. Both plans cost the same and both advertise 5-minute checks. Distill includes 100,000 cloud checks and Visualping includes 5,000, so one of them holds 11 pages at that speed for a month and the other cannot hold a single one. Visualping sells Personal 5K with 20 pages on it. The pages are real and the frequency is real, and you cannot have both at once.
None of this makes Visualping a bad product. It does several things the others do not: screenshot comparison with the changed text picked out, an AI judgement on whether a change matters, SMS alerts, a Google Sheets integration, and monitoring of pages that need a sign-in. If you check a policy document twice a day, the quota never bites and those extras earn their money. We put it against us properly on the Visualping alternative page.
If you are comfortable with Docker, probably yes. The project is Apache-2.0 and starts with one command, `docker compose up -d`. It tracks text in PDFs, and their filesize and checksums, filters with XPath and JSONPath, and sends alerts through Apprise, which covers Discord, Slack, Teams, email and a long tail of others. Nobody meters you, because there is no plan to meter.
The hosted version is $8.99 a month for up to 5,000 URLs, with re-checks "from 5~ minutes (per runner - with the ability to easily add more Chrome Browsers)". Per URL that is the cheapest thing on this page by a wide margin. What you take on instead is the upkeep: a box to keep patched, a browser to keep updated, and your own IP address doing the fetching, which matters more than people expect on retail sites.
Two reasons, and neither is about price. The first is speed. Nothing in that list checks faster than every 2 minutes, and Visualping sells that speed from $70 a month. A popular restock is over well inside two minutes. The second is noise. A shop page redraws itself all day for reasons that have nothing to do with stock, so a tool comparing today against yesterday has to be taught which parts to ignore before it is any use.
The choice is between two different jobs. A general differ points at any page on the internet and tells you it changed. A platform-aware monitor reads the shop's own product data and tells you a size came back. We built the second kind, which is why we cannot watch any page on earth the way Visualping can. Our guide to monitoring a website for changes covers where each one fits, and why restock alerts arrive too late sets out the limit that applies to every tool here, ours included.
Work out your check budget first
Pages multiplied by checks a day multiplied by 30. Two pages every 15 minutes is 5,760 checks a month. Compare that with the allowance before you compare anything else, because it is the number that pauses you.
Decide whether you need a picture of the change
If somebody has to see what moved on the page, Visualping's screenshot diff is the reason to pay for it. If you only need to know that a value flipped, you are paying for rendering you will never look at.
Check whether the page needs a login
Most of these watch public pages only. Visualping's Actions feature is the exception on this list. Anything behind your account, like a delivery slot picker, is out of reach for a tool that is not signing in as you.
Ask what happens when the site fights back
A page behind a bot check does not fail loudly. It answers with a challenge page, which a differ will happily watch forever while reporting nothing. We wrote up what that wall is in our guide to why a website says verify you are human.
Match the interval to the thing, not to the plan
A council planning page can be checked daily. A competitor's pricing page, hourly. A product that sells out in 90 seconds needs seconds, and only one product on this page offers that.
| Price | Pages or monitors | Fastest interval | Monthly check quota | |
|---|---|---|---|---|
| Visualping Free | $0 | 5 pages | 60 minutes | 150 |
| Distill Free | $0 | 5 cloud monitors | 6 hours | 1,000 |
| PageCrawl Free Forever | $0 | 6 pages | 60 minutes | 220 |
| changedetection.io hosted | $8.99/mo | 5,000 URLs | About 5 minutes | None published |
| StockWatch Free | £0 | 5 monitors | 60 seconds | None |
| StockWatch Standard | £4 a month | 50 monitors | 15 seconds | None |
Our free tier has a limit too, and it is not a check count. Free monitors run through your own browser or your own proxies rather than ours, because giving away cloud requests to shops that rate-limit hard would cost more than the plan earns. Free also gets Discord alerts and 30 emails a month rather than unlimited email, which happens to be the same email allowance Distill gives away. £4 a month drops the floor to 15 seconds and puts three monitors on our proxies. £20 a month takes it to 5 seconds.
It depends which limit you hit first. PageCrawl's free tier includes the most checks of the metered ones at 220 a month over 6 pages. Distill's free tier includes 1,000 cloud checks but nothing faster than every 6 hours. Visualping gives 150 checks over 5 pages at 60 minutes. Self-hosting changedetection.io removes the quota entirely if you are happy running a server. Figures checked 9 September 2026.
On checks per dollar, Distill, and it is not close. Both charge $35 a month for their mid plan. Distill Professional includes 100,000 cloud checks and Visualping Personal 5K includes 5,000. Visualping earns its price on features instead: screenshot comparison, SMS, and monitoring pages that need a login.
In the cloud, the published floors are 6 hours on Distill Free, 60 minutes on Visualping Free and PageCrawl Free, 15 minutes on the entry paid plans, 5 minutes in the middle, and 2 minutes at the top of Visualping's list. Nothing on any of these price lists goes below 2 minutes.
Not at Visualping, which states plainly that checks do not roll over monthly and that monitoring pauses when the allowance is gone. Treat every allowance as use-it-or-lose-it unless the tool says otherwise.
Visualping offers it through its Actions feature. The others on this list are built for public pages, and so are we. If the thing you want to watch sits behind your own account, no third-party tool is going to reach it without your credentials.
Watch a page for the moment it changes Five pages free, checked every 60 seconds, no monthly check quota. Alerts to Discord, email or Telegram.