# Online inventory trackers?!  How do they work?

**URL:** <https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052>\
**Category:** Factual Questions\
**Created:** [July 3, 2006, 3:16pm UTC](https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052 "2006-07-03T15:16:47Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![cymbal.rush](https://avatars.discourse-cdn.com/v4/letter/c/ce7236/32.png) [@cymbal.rush](https://boards.straightdope.com/u/cymbal.rush)\
**Post date:** [July 3, 2006, 3:16pm UTC](https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052/1 "2006-07-03T15:16:47Z")

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Remember the XBox 360 shortage fiasco? I do. I waited 18 hours in the freezing cold to score one. Well, online tracker sites, such as [this one](http://xbox.clambert.org/) made it easy for folks to locate where the product was in stock. How does a site like this work? What’s involved? I’d like to create one on my own. Please advise. Thanks!

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**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\
**Post date:** [July 3, 2006, 3:48pm UTC](https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052/2 "2006-07-03T15:48:42Z")

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Probably little more than a bunch of bots to periodically ping vendor sites to see what the stock levels are.

Some sites do reveal stock levels to shoppers - Amazon, for one, will say something like “only four left, order soon!” and at this moment the eBay link yields “227 items found…” Or, they’ll say “Sorry, this item is out of stock.” Either condition should be pretty easy for a bot to determine.

Others might allow (knowingly or otherwise) the bot more direct access to query their underlying database.

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**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\
**Post date:** [July 3, 2006, 3:49pm UTC](https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052/3 "2006-07-03T15:49:31Z")

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As the verbaige on the home page says, they’e written compuer programs to visit each retailers web site every few minutes & check stock. The programs probably “pretend” to be an ordinary human web surfer & they read the catalog pages they get back looking for either a quantitiy in stock or an indication of out of stock/ on back order, etc.

if you are a dedicated computer programmer you could probably do somthing like this investing only 30 or 40 man-hours per different retailer who’s site you want to access.

if you don’t have those skills, well, you’d as easily build your own car from a pile of iron ore & some plastic pellets.

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**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\
**Post date:** [July 3, 2006, 8:59pm UTC](https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052/4 "2006-07-03T20:59:48Z")

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> [@LSLGuy](#):
>
> if you are a dedicated computer programmer you could probably do somthing like this investing only 30 or 40 man-hours per different retailer who’s site you want to access.

More like one or two man-hours. Writing web bots is pretty trivial.

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**Author:** ![cymbal.rush](https://avatars.discourse-cdn.com/v4/letter/c/ce7236/32.png) [@cymbal.rush](https://boards.straightdope.com/u/cymbal.rush)\
**Post date:** [July 3, 2006, 9:10pm UTC](https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052/5 "2006-07-03T21:10:18Z")

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Hi friedo, can you point me to any resources on the web? Thanks!!

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**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\
**Post date:** [July 3, 2006, 9:19pm UTC](https://boards.straightdope.com/t/online-inventory-trackers-how-do-they-work/363052/6 "2006-07-03T21:19:48Z")

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[Here ya go](http://search.cpan.org/~petdance/WWW-Mechanize-1.18/lib/WWW/Mechanize.pm).

Have fun. But don’t do anything that would annoy the owner of the websites in question.