Every product sold at Amazon.com has its own page, which has a unique address (or URL). The link can look like this:
A link that looks like the one above is all that is needed to link to a product page on Amazon. The 10-digit number (which may also contain letters) is the ASIN - Amazon Standard Identification Number - which Amazon assigns to every product they sell. For books with a 10-digit ISBN number, the ASIN is the same as the ISBN number (though there may be some exceptions). ASINs for products other than books will contain letters as well as numbers.
I started to notice the above format in Amazon links around 2008. Previously various other formats were used, some or all of which may still work.
This is the earliest format I found -
Later I noticed that the exec/obidos portion of the link could be replaced with the letter o, like this:
Later (2005-2006), I found this format:
And starting around September, 2006, Amazon began to use links that include some words from the title and author, such as:
In September of 2008, I discovered this format:
(note- if you change that "dp" to "gp", it will not work, unless you add "/product", as in the example above).
There are several reasons why you will see much longer links. One is that Amazon tracks every page hit, and one is that Amazon has a referral program. Also, there are different ways to link to the same page, which result in different URLs.
When you follow a link to a page on Amazon, even if it is a simple link like the one above, you will see in the address box on your browser that the URL is much longer. This is just tracking info. Since this is confusing and since Amazon doesn't really explain it, many people assume this long URL is the actual address to the page. So when people capture a link (like to email to someone or to put in a document or to keep as a bookmark), they usually capture the whole long link, which is really just a temporary unique URL for that particular page hit. All you need to include is just up to the 10-digit ASIN. Another confusing thing is that Amazon will sometimes take you to a product page other than the main page for the item, and the link may be structured differently. But all products should have a page with a link like the simple one above.
One of the cool things about Amazon is that they let anyone sign up for a referral program. You can have a virtual bookstore on your website by linking to pages at Amazon. If links from your site result in sales, you get a commission. When a link from a site is part of this program, there will be an identifier at the end of the URL so Amazon knows who to credit for the referral. So this is another thing that results in extra characters at the end of the normal Amazon link. You can tell if a link from a site is part of this program by looking at the link in the source code for the page (or just move your mouse over the hyperlink and see what shows up at the bottom of the screen). Also, participants are supposed to clearly indicate that they are affiliated with Amazon.
Amazon.com is a massive and very technically complex operation. The above info is just stuff I have figured out from observation. There are exceptions and additional stuff that I haven't seen or figured out and anything could change at anytime.
So far, from the time I began to develop my website in 1999, I have not participated in Amazon's referall program. I have many pages on my site which link to Amazon for more info on books, CDs, DVDs, etc. Since I don't want anyone to think my recommendations are skewed by profit motives, I do not earn any commission from Amazon for the many links I make to them. I may someday change my mind about this, but for now that's how it is and that is the main reason I made this page - to explain the technical details sufficiently for anyone to verify that all of my Amazon links are "clean". Another reason I made this page is that I'm always kind of annoyed by massively long links that people post to Amazon pages and I figure some people wouldn't mind learning how to do this correctly.
JAN 2007 - I discovered that the long links for Listmania lists can be cut down to just http://www.amazon.com/lm/xxxxxxxxxxxx/ where xxxxxxxxxxxx is the ID number of the list (I've seen 13 and 14 digits).
See also -
Wikipedia article on Amazon ASIN numbers -
Wikipedia article on ISBN numbers -
Wikipedia article on URL (web addresses) -
Slade's Home Page
Revised 05/04/22, 08/31/08 (originally posted 12/02/00)