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The Truth About Backend Keyword Search Indexing on Amazon

By Anthony Lee

Is there really a hard limit on Amazon listing "backend" search terms? Anthony Lee has the definitive answer on limits and a lot more.

The Truth About Backend Keyword Search Indexing on Amazon

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Keith OBrien

Anthony this is solid. It confirms most of what we have found and reported on with one exception.

We have found almost exclusively that new listings all fall around the 250 character limit…so I think saying it’s a myth is a bit misleading.

Older listings are a whole different ballgame and agree it seems unique to a listing/category.

Anthony Lee

Replying to Keith OBrien

Keith, I totally understand what you are saying.

I wasn’t trying to be misleading, but the concept if it being a myth involves more than just character count. Its the hysteria that surrounded the “change,” and the fact that so many people were sure that their listings had changed and they were losing impressions and sales because of it. Then, bad advice on how to handle it was coming from both seller central AND experts.

Regarding your statement, while I did mention in the article that this may not be the case for new listings, I am still skeptical until proof is provided.


Replying to Anthony Lee

I totally agree, Anthony. The first article I saw that came out was really poorly done, which is why I responded with my own after we did a bunch of testing.

Not sure if you read it, but our findings were pretty similar and our feedback to sellers was pretty similar.

We’re going to keep testing on this as some of our data on duplication and such is a little different.

Anthony Lee

Replying to Keith

I think one of the issues we are running into is that people don’t know how to test properly or interpret the data properly.

In my humble opinion, the best way to test moving forward…if you have a NEW listing, fill out the front end with ONLY your big key terms but leave it as bare bones as possible with NO search terms in the back end. Then check indexing on those key terms. THEN add less than 250 characters to the back end, all of which are NOT in the listing. Then check to see if they index.

Then add more than 300 characters to back end and test again. Then flesh out the entire listing as much as possible and check again. This will test for character limits in the back end AND in the listing as a whole.


Replying to Keith OBrien

I think Keith has a point. Experiments that we’ve contacted on our own account last week and on friends accounts that we pushed to do the same tests show inconsistencies.

Seems like new listings (new being somewhere around March/April) are only ranked for 250 characters (Beauty category). Exceeding 250 with a few characters invalidates all back end search terms, so you will not rank for any of those, except where the word is also in Title, Bullets or Description.
We’ve noticed some correlation between answered questions content and ranking.
Older listings and accounts, were RANKED for keywords that appear only on the search terms, and not in the visible listings. Even with 2000+ characters. Those are again, old accounts and listings made prior to 2017. So there’s inconsistency and it may be that Amazon is rolling out a limit or what not.
One more thing we figured out – if you put completely irrelevant words in the search terms, and limit to 250 characters (in a new listing) it ranks. Why would it do that I have no idea, no one is looking for skin oil in conjunction with “Skittles” or “Salad”… but it does rank (makes you think, doesn’t it?)
Another thing – it works with your competitor’s name too – but AFAIK it’s not supposed to rank on competitors names.

Anthony Lee

Replying to Eran

“if you put completely irrelevant words in the search terms, and limit to 250 characters (in a new listing) it ranks.”

Umm. This is definitely something I’d like to see more evidence on. Because if that is the case, it completely flies in the face of why the change was made in the first place (to ensure relevancy).


Replying to Anthony Lee

Hi Anthony,

Here’s what we did, step by step, without revealing too much information about our listings:

1) Tested 2 new listings and 2 old listings in 1 account that exists since January 2017.
Then – I tested 2 old listings in an account that opened before 2017, with 2 of their oldest listings.
2) I’ve separated in all ads words that appear in the ad and in the search terms and words that are not (exclusive for Search Terms).
3) I manually tested (it took a few hours, yes), a large (too large) sample of words from each group in several accounts.

So far the discrepancy was great – old accounts showed ranking for more than 2000 characters, while new accounts showed no rank (I checked all words that do not appear in Title Bullets Description).

So I left the old accounts alone for now, then performed the following on the 2 new listings in the newer account:

1) Backed up all search terms
2) Deleted all search terms
3) Saved
4) Went into edit again, and added only 20 keywords (came to be close to 200 characters with the spaces, no comas or special characters).
5) The 20 keywords that I’ve re-added were split into groups: Competitors brand names, Irrelevant keywords and relevant keywords.
6) Saved than waited about 15 minutes
7) Rechecked in both listings, manually and all keywords in search terms rank, including Skittles (for oil, I mean give me a break), Trump and Salad. The competitors ranked as well. (now let’s discuss this as an ethical issue?)

It’s interesting, because if under the new algorithm Amazon ranks back end keywords (all of them) if you limit to 250 characters – you can actually choose what will rank and what will not rank.

3 notes, if you read thus far, it may be interesting:
1) Specific keywords that didn’t rank when there was more than 250 characters in the new account, now ranked when it was under 250. (That would support the claim that over 250 keywords invalidates the entire back end search terms… – again I’m not claiming it is, but surely in some cases it does, possibly new accounts.
2) This should be repeated over time probably. It may be that when making changes in the Search Terms Amazon does give you a ranking, and after a while, after the algorithm recognizes that Skittles and Oil have no correlation and nothing to do with each other – maybe it will stop being ranked… We’ve only conducted this experiment last week, not enough time has passed.
3) Different categories – We have only tested Beauty. Have no idea (and also less interest at the moment) in how other categories behave… Got to keep a focus, right?

I have to say one more thing – your article, is BY FAR the most comprehensive that I’ve seen about this specific topic, specifically relating to all the buzz lately around the limitation (or lack of) of back end search terms.
I’ll be happy to pick up more gems in the future, I see you’re working on a book and that could be interesting and I encourage all Amazon sellers out there, small or big to take action and expand their knowledge in every occasion they have.

Anthony Lee

Replying to Eran

Wow. That is some great info. Thank you.
This completely turns a theory I’ve been working on onto its head, but it is good information.
I’ll add another dimension to my tests when I launch my new products in the next month. I would really like to see if we continue to have control over indexing and ranking for irrelevant (or otherwise whatever we choose) terms.

Ivelin Demirov

Replying to Eran

Completely irrelevant keywords will rank initially and then will be deindexed in a week or so.


So, if keyword entered in Search term section indexed only if it exist also in visible part of listing, it looks like search terms have no any sence to fill out.

Anthony Lee

Replying to Alex

It almost seems that way, but the jury is still out as to whether or not this is the case with NEW listings.
If you have an old listing, just reduce your back end search terms to single keywords found within the listing text. That way, at least they will index individually as well as in phrase format.
If you have a NEW listing, you should test to see if back end search terms that are NOT found in the listing itself index. If this is the case, you get more room for keywords you don’t have to weave into the text of your listing. However, so far no one has provided proof of this, so you won’t know unless you test.


the 250 character limit is active at least on and on

FR: If you want to list a product in FR and you have more than 250 characters you get an error and the product is only listed if you go under 250.

DE: As soon as you have more than 250, no keyword is indexed anymore. We had that problem with more than 100 ASINs. After removing keywords and go under 250 characters, the listings were findable after a few minutes.

Category was Kitchen & Baby

Anthony Lee

Replying to bernd

Thank you for sharing this information. I encourage anyone who is uploading NEW listings to test and find out how your individual category on your marketplace is reacting.

Marco Tassiano

Great and solid article Anthony. Thank you.

I think all people working as Amazon SEO should be grateful.
On our side, we tested a lot, with a similar “scientific approach”, and can confirm a progressive reduction of “accepted” search terms, most probably due to the fact that A9 is evolving towards more complexity. Therefore AMZ prefers to index higher and higher a relatively lower number of sellers i.e. the once that are able to discover and spread on their listing the extremely high relevant KW and search terms only. After all, they like much more to manage only 1 seller that develops 100,000 USD/YEAR of turnover (as he knows how to optimize) rather than 25 sellers that, all together develop the same amount of sales..

Karen Holmes

Thank you so much for this detailed article. You have confirmed everything Lisa Suttora has tested and taught in her group, and whilst I trust her knowledge you are the only other person I have read about that has had the same observations. I like how you presented it. It was very informative and easy to understand. Thanks.

Matt K

There’s one important piece you’re missing here. There seems to be a cut-off date somewhere between March-May where Amazon made a change. Keywords added BEFORE that date are continuing to index. Keywords added AFTER that date are not, beyond the 250-character limit. We tested and verified this for a large number of products.

Matt K

Replying to Matt K

“We’ve established pretty clearly that keywords in the search term area only index IF they are also somewhere in the visible listing.”

This is also inaccurate. I’ve tested with gibberish character strings only in search terms, not in the listing ,and had our listing show up.

Anthony Lee

Replying to Matt K

I am not saying you are wrong, but this was our finding across multiple categories, as was illustrated.

If you have contrary evidence, please, by all means present it.

Matt K

Replying to Anthony Lee

I can’t share client data, but we added multiple keywords to the effect of ‘thisistestkeywordnumberone’ to ONLY back end search terms and had listings show up for those searches within 60 minutes.

Anthony Lee

Replying to Matt K

I think the article mentioned that we haven’t been able to test this on NEW listings. Another issue I see people running into is not properly testing in each category.
As in, people are making bold claims that bullets are no longer indexed, largely because of the wonkiness where Amazon chooses to index only phrases and not individual words, then they test for individual words.
The best way to test this is by creating a listing from scratch and testing at every level.
And, the other important thing to note here is, if new listings do have a hard limit, yet all keywords in the listing still index, what benefit is there to having back end keywords at all?

Keith O'Brien

This is a super juicy topic. This is part of the reason many of us on this thread as consultants and service providers have busy businesses…this stuff is difficult.

Thanks for everyone continuing to contribute to this thread.

Amazon is a wonderful, ever-changing platform that as Bezos says, “is always in Beta.” It’s never stagnant and we can’t be as well.

I’m always reminded that just because we see something one way…it doesn’t mean there aren’t many other profitable, sound ways to get the same result.


Here’s the feedback from our SVS rep – August 2, 2017

Following up, below are the recommendations on generic keywords as discussed.

* There is a new length limit of 249 characters, including spaces, for Generic Keywords.
* If an ASIN’s generic keywords exceed this limit, none of the generic keywords are indexed.
* Generic keywords can have all lower case letters. There is not restriction on this.
* There is no need for punctuation e.g. ; : ,
* Words do not need to be repeated in the Generic Keywords field. Once is enough.
* No need to repeat words that are mentioned in other indexed fields, such as title and description.
* It is sufficient to include either singular or plural of words. It is advised to use whichever is searched for the most. For example, “headphones” is searched for more than “headphone”. We advise a “test and see” approach as to whether to include singulars and plurals of words or not.
* No need to include the ASIN’s own brand name in its Gen KWs.
* It is not allowed to include other brand names or ASINs in Generic Keywords.
* No need to include adverbs (nearly, really), pronouns (I, she, him), prepositions (after, in, to, on), conjunctions (and, but, for, if, or), determiners (a, an, the), superlatives (best, cheapest, rarest).

Search indexes Generic Keywords to a larger extent than Subject Keywords. For subject keywords, the character limit is 2000 characters and includes delimiters. For subject keywords, same guidelines as above.


Amazon posted now something about that in Sellercentral UK, so it is official:

Amazon launched a feature that limits the length of the generic keywords attribute to less than 200 bytes in the IN marketplace, 500 bytes in JP and 250 bytes in every other marketplace except CN. The limits have been shown to improve the quality of search results. It applies to newly registered and existing ASINs.

Key Guidelines:

Keep content within the prescribed length limit (less than 250, 200 for IN, 500 for JP):
Length limit applies to total content in all generic keyword fields (a max. of 5 attributes).
Whole entry will be rejected upon exceeding limit.
Number of bytes equals number of characters for alphanumeric characters (e.g. a-z, 0-9) while other characters can be 2 bytes or more. Examples include ä (2 bytes), £ (2 bytes), € (3 bytes) or ❤ (3 bytes).
Spaces and punctuation (“;” “,”, “.”) do not contribute to the length limit, but words should be space-separated. Punctuation between words is unnecessary.
Optimising keyword content for search discoverability:
Do not include keywords that are not descriptive of the product.
Do not include brand names (even your own) or other product identifiers.
Do not duplicate content present in other attributes, such as title and bullet points.
No need to repeat keywords; once is enough.
Use keywords that are synonyms, hypernyms or spelling variations of content in visible attributes (e.g. if product title is ‘whiskey’, use ‘whisky’ in generic keywords).

Jose Martin

Hi I am a bit new in all of this and had a few questions hopefully one of you can help me. If I understand correctly in the 250 character limit I should not include any of the words that are already in the title or the description as it already gets indexed for?
2 When indexing for specific words, have you done any tests as to wether words in plural encompass word in singular? For example putting photos would mean I dont need to write photo as those characters are already included in the name?

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