Show HN: Price changes alerts for any store

I worked on a product like this for a long while, so I can appreciate how hard the problem is you are trying to solve. Some things I realized along the way:

* Price capture needs to happen in a headless browser (e.g. PhantomJS), rather than just capturing the HTML with a GET. Too many sites use JavaScript to make raw HTML analysis feasible.

* You can get > 50% of the pricing information with fairly simple matching on the class/id value in the HTML tag. But you need a headless browser to make sure the tag is visible. And since most product pages contain multiple prices, you need some heuristic to determine the relevant price. Oh, and watch of out for "reduced from" prices too (e.g. "Old Price: $50, New Price: $35".

* It doesn't hurt to be able to override the general heuristic on a domain-by-domain basis, saved me a lot of headaches.

* You need to be honest with yourself about how reliable the price capture algorithm is, and built up a regression database of known good pages, so when you change the algorithm, nothing else breaks. Also, you need to keep ahead of site redesigns!

* Product URLs tend to look messy, but tend not to change very often, if at all. I was worried about retailers e.g. changing product identifiers, but changing URLs hurts their SEO, so they don't do it. You will find "zombie" products, though - things which appear to be still on sale, but aren't linked anywhere on the site. Deciding when a product is sold out is tricky.

* The best user experience presents the items the user is watching as a "shopping basket". (I took design cues from Pinterest.) For a really slick experience, you should pick out the product name and image (Facebook meta-data helps here) and include them in you "pinned" products.

* Cutting-and-pasting URLs is a hassle. Consider writing a browser extension or a bookmarklet - users don't like to have the browsing flow interrupted by having to click across tabs. Having the price capture done inline on the page really impresses people.

Best of luck with this! I'm yet to see someone solve this problem well, and I eventually moved on other things after losing a lot of my hair. :-)

adibalcan18• 10 years ago

Really interesting feedback. Thanks!

mikeash• 10 years ago

I'd suggest a more descriptive title here. From the title, I thought/hoped it would give me price info for local stores, not just online. One of my constant annoyances is the fact that it's difficult if not impossible to find the lowest price for grocery items without physically visiting the stores you want to survey.

adibalcan18• 10 years ago

You are right. Thanks for feedback.

Egidius• 10 years ago

Alternative: https://pricep.in/

adibalcan18• 10 years ago

This is based on an unique technology which detect price on product pages on various stores

ajmurmann• 10 years ago

What makes it unique? Since this is HN a few more details would be appreciated.

adibalcan18• 10 years ago

It's an heuristic algorithm which detects price element (as CSS selector) without any specific configuration

throwaway2016a2• 10 years ago

I too am curious, price detection is a very well trodden area.

I've seen page structure analysis, manually Xpath/CSS selector writing, machine learning, pattern matching, micro-formats, large central databases, etc.

I understand that no company wants to unveil their secrets but this is Hacker News. If you're going to promote your product here at least give us something tech to munch on.

forvelin• 10 years ago

How it is different than pricep.in ?

throwaway2016a2• 10 years ago

Or a half dozen or more other sites that have done this.

I think using heuristics as mentioned in one of their previous answers might be somewhat novel. But yeah... I worked on a product that did auto-detection of which element was the price on a page at least five years ago. I'd love to learn the differentiators.

speg2• 10 years ago

Well, the first page[1] I tested it on worked fine, whereas pricep.in seemed to fail. Also, I didn't need to create an account or install an extension.

[1] https://www.lowes.ca/routers/dewalt-dwp611pk-125-hp-variable...

pravda• 10 years ago

Internal Server Error

The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.

adibalcan18• 10 years ago

the server is overloaded. We will fix soon

adibalcan18• 10 years ago

now works :)

adibalcan18• 10 years ago

We have to many visitors from HN

6DM4• 10 years ago

Just curious, what kind of traffic levels are you seeing from HN. Just in case any of us want to do a load test to validate our own sites can handle it.

jastr• 10 years ago

Top 5 on HN for ~3 hrs peaked around 1,500 views per hour

denzil_correa• 10 years ago

Is this market specific? I tried this product [0] and it tells me the product has a price of 32 rather tahn 13,999/-.

[0] http://www.amazon.in/dp/B01DDP7GZK/ref=br_imp?pf_rd_m=A1VBAL...

adibalcan18• 10 years ago

It's heuristic

tmaly• 10 years ago

You might want to update your version of Nginx and add some caching I am getting a 504

nginx/1.4.6 (Ubuntu)

adibalcan18• 10 years ago

Thanks for feedback, we will fix this

prawn• 10 years ago

Provide a link or two as examples so people can quickly try it out. Make it clickable rather than something they have to copy and paste. Maybe have a grid of popular products for this. This allows people to try your service and also gives them ideas of the types of products they might track.

I could see something like this being a really quick way to get alerts when a competitor changes their price. Not sure if there would be legal issues in promoting this though.

In the text here ("Enter your email in the field above for future price notifications"), the field is below, not above. At least, it is in my browser.

adibalcan18• 10 years ago

Good idea! We will change as soon as possible.

adibalcan18• 10 years ago

Done

kkotak• 10 years ago

These can be shutdown very easily by the sites if they want to.

JustSomeNobody• 10 years ago

Why yes they can. But, is it in their best interest to devote much resources to the endeavor?

the_unknown• 10 years ago

Could be. If they don't want to compete solely based on price. Or don't believe that price is their strong point.

There are many reasons to compete on price but just as many reasons to not compete on price including service, support, delivery charges, home delivery options, shopping local. Or simply not wanting to support a race-to-the-bottom Walmart world.

Yes, forcing retailers to be part of your system is great for your business model but that doesn't equate to necessarily be good for theirs. And since they may never know that you even exist (if a customer doesn't visit because of your site how will they know?) they may be losing traffic without even knowing why.

zlagen• 10 years ago

Here's an alternative for heuristic extraction which appears to handle more complex data: https://www.diffbot.com/

dtsn• 10 years ago

Alternative for the UK http://pricehare.com

vjandrea• 10 years ago

Why the currency isn't specified? I'm looking for an item on Amazon France and the price should be dispayed in euros, not in USD.

adibalcan18• 10 years ago

We get the correct price but we strip currency (for numerical comparison)

rgx102• 10 years ago

Gives internal server error when clicked go without a link

adibalcan18• 10 years ago

Try now ;)

rgx102• 10 years ago

Gives a server error when clicking go and no link is entered

mtgx• 10 years ago

Couldn't this work as a browser extension instead?

blawson• 10 years ago

Another one I wrote for my friends and I a while back:

https://salesniper.com

coldshower• 10 years ago

That's a great domain name. Did you register it or have to buy it from someone?

adibalcan18• 10 years ago

we have registered it

swalsh• 10 years ago

This is a really great way to mine data. Seriously as an eCommerce store i'd pay for access to this data.

Let me send you a product feed, and let me know any time a customer requests something from it (on my site or someone elses) I'll send them a deal email.

adibalcan18• 10 years ago

Please use this form to contact us: https://thewebminer.com/contact

irrational• 10 years ago

So, it's like camelcamelcamel, but for more sites?

Show HN: Price changes alerts for any store

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