Amazon SEO in 2026: What Amazon Documents and What the Industry Made Up
Amazon search ranking rests on the fields Amazon indexes. Those are the title, Item Highlights, bullets, description and backend search terms. Amazon publishes character limits for them. It publishes no ranking weights, no algorithm name and no pricing formula. Most guides fill that gap with invented detail. This page separates what Amazon documents, with the URL and the date, from what the industry repeats with nothing behind it.
What Amazon SEO means in Amazon’s own words
Amazon makes one plain statement about ranking. A sidebar on its seller blog reads: “Listing quality and your account health can contribute to search rankings”.
That is the whole mechanic on offer. The rest of the page covers titles, images, keywords and price. None of it says how those inputs feed a ranking function.
Read what the sentence avoids. It names no weights and no order of importance. It says “can contribute”, not “determines”. Amazon documents inputs and withholds the maths. Start there and the invented parts of the standard advice become easy to spot.
A9, A10 and COSMO, sorted out
A9 is a company name. A9.com was an Amazon subsidiary founded in 2003 that built search technology. Amazon retired the site in 2019 and the group folded into Amazon Search. No Amazon paper, help page or announcement names A9 as the product ranking algorithm. The industry named it that, and the top results still teach it.
A10 has no Amazon source of any kind. No paper, no help article, no announcement, no patent. It is a community invention that spread because it sounded like a version number.
COSMO is real and well documented. The SIGMOD 2024 paper on Amazon Science describes a commonsense knowledge graph built from shopper behaviour. Large language models generate candidate knowledge. Human annotators score a sample, and a classifier trained on those scores filters the rest. Amazon describes COSMO as deployed in search applications such as search navigation.
The reported gains matter less than people assume. Amazon’s research blog of 10 May 2024 reports macro F1 improvements on the Shopping Queries Data Set from KDD Cup 2022. That is a public benchmark, not live ranking. Anyone saying COSMO replaced A9 is stacking unverified claims.
Claim versus source, side by side
We run this table before any listing project. A claim with an empty source column does not get acted on.
| Claim | Documented | What Amazon actually says | Source and date |
|---|---|---|---|
| A9 is the ranking algorithm | No | Nothing. A9.com was a subsidiary site Amazon retired in 2019. | No Amazon source exists |
| A10 replaced A9 | No | Nothing at all mentions A10 | No Amazon source exists |
| COSMO is the new ranking algorithm | Partly | COSMO runs in search applications such as search navigation. Its gains come from a public benchmark. | amazon.science, SIGMOD 2024 |
| Pricing within 5 to 12 percent triggers a boost | No | Competitive pricing “can improve your product ranking”. No band, no threshold. | Amazon seller blog, 3 September 2025 |
| Descriptions cap at 2,000 characters | No | No reachable Amazon page states this | Not published by Amazon |
| Bullets cap at 255 characters | No | The seller blog gives 100 characters per bullet. | Amazon seller blog, 3 September 2025 |
| You get seven image slots | No | Amazon recommends at least six images and publishes no slot count. | sell.amazon.com/blog/product-photos, 4 December 2024 |
| Amazon penalises keyword stuffing | No | No named penalty. Amazon enforces caps instead | Seller Forums, 21 January 2025 |
The 75 character title rule
The rule is short. Amazon’s Seller Forums announcement of 10 June 2026 says: “Starting July 27, 2026, titles in all categories except for media will need to be 75 characters or less including spaces”.
Amazon then handles the rest for you, which is the part sellers miss. Its wording: “After July 27, any titles still over 75 characters will be updated to the AI recommendation gradually”.
Brand owners get a window first. Amazon states that they “will have 14 days before implementation to review, modify, and approve AI-generated recommendations”. The View enhancements area inside Manage All Inventory is where you act. We cover the 75 character title rule in detail separately, because the edge cases fill a page of their own.
Now the contradiction. Amazon’s marketing blog still tells sellers that titles allow 200 characters, with 60 recommended. Read the seller blog page updated 3 September 2025 beside the forum announcement. Two Amazon properties, two numbers. The announcement is the operative one.
Item Highlights, the field almost nobody covers
The same announcement introduced a field most guides have skipped. Amazon describes it this way: “Item Highlights provides an additional 125 characters for sharing materials or recommended use cases that help customers compare options. This content is searchable and visible with titles in search results and on product detail pages”.
Searchable, and shown next to the title. That makes it the first home for a displaced keyword.
Cutting a title from 190 characters to 75 strips roughly 115 characters of indexed text. Those words have to land somewhere or the coverage goes. Order the move by field, not by preference. Good Amazon keyword research tells you which terms earn the 75 characters and which move down.
| Keyword type | Best field | Why | What to avoid |
|---|---|---|---|
| The head term shoppers type | Title | 75 characters, read first, highest visibility | Padding with synonyms |
| Material, size, fit, use case | Item Highlights | Searchable and shown with the title | Repeating the title word for word |
| Benefit and feature phrasing | Bullets | 100 characters each, and shoppers read them | Warranty and legal text |
| Long tail and question phrasing | Description or A+ Content | Room to answer real buying questions | Dumping a keyword list |
| Spelling variants, abbreviations | Search terms | Hidden from shoppers, still indexed | Words already in the title |
| Articles and prepositions | Nowhere | Amazon’s guidance says to skip them | Spending bytes on “the” and “for” |
Search terms is 250 bytes, not 250 characters
The current top result gets this wrong. Amazon’s announcement text, quoted in the Seller Forums, reads:
“Keep content within the prescribed length limit (less than 250, 200 for India, 500 for Japan): Length limit applies to total content in all generic keyword fields (a max. of 5 attributes). Whole entry will be rejected upon exceeding limit”.
Three details carry weight. The limit is a combined total across up to five generic keyword attributes. Filling five boxes does not buy five allowances. The unit is bytes, so an accented or non-Latin character eats more than one. And Amazon rejects the whole entry on overflow instead of trimming it. One extra character can quietly cost you every backend term.
Amazon’s own guidance is short. Use lowercase, separate words with spaces only, skip articles and prepositions, and skip anything already in the title or bullets. Duplication buys nothing.
Every other limit Amazon publishes
Two title rules survived the cap. The January 2025 announcement bans a set of special characters, listed as “!, $, ?, _, {, }, ^, ¬, and ¦”, unless they belong to the brand name. It also states that “titles may not contain the same word more than twice”, with prepositions, articles and conjunctions excepted.
Two widely repeated limits fail the source test. The 2,000 character description cap and the 255 character bullet cap appear in no Amazon page we can reach. The seller blog gives 100 characters per bullet and no description figure at all.
| Field | Current limit | Unit | Source | Last confirmed |
|---|---|---|---|---|
| Title | 75 | Characters including spaces | Seller Forums announcement | 27 July 2026 |
| Item Highlights | 125 | Characters | Seller Forums announcement | 27 July 2026 |
| Bullet point | 100 | Characters per bullet | Amazon seller blog | 3 September 2025 |
| Description | Not published | Not published | No reachable Amazon page | Not applicable |
| Search terms | 250 | Bytes across five attributes | Seller Forums, quoting Amazon | Announcement text |
| Image alt text | Not published | One sentence with one or two keywords | Amazon seller blog | 3 September 2025 |
Images, sourced properly
Amazon’s product photo guide of 4 December 2024 gives the accepted range as “500 to 10,000 pixels on their longest side”. It adds: “We prefer images larger than 1,000 pixels on each side to allow for zoom”. The framing rule is firm: “Have the product fill 85% or more of the frame”. JPEG is the preferred format.
The 1,600 pixel figure sits on Seller Central’s image standards page, which blocks crawlers. Sellers quoting it in the forums give the wording as “Images should be 1,600 pixels or larger on the longest side”.
On quantity, Amazon recommends at least six images plus a video. It publishes no number of image slots, so we do not quote one. The seven slot figure that circulates has no Amazon source.
| Dimension | What it enables | Source |
|---|---|---|
| 500 pixels, longest side | The floor for display on the site | Amazon product photo guide, 4 December 2024 |
| 1,000 pixels, each side | Turns zoom on | Amazon product photo guide, 4 December 2024 |
| 1,600 pixels, longest side | The recommended working standard | Seller Central image standards, quoted in the forums. |
| 10,000 pixels, longest side | The ceiling Amazon accepts | Amazon product photo guide, 4 December 2024 |
Price and ranking, honestly
Amazon makes one link between the two. The seller blog says: “Adjusting your list price to stay competitive can improve your product ranking and increase sales”. That gives a direction. It gives no threshold and no formula.
Now the claim that runs through this industry. Pricing within 5 to 12 percent of the market average supposedly triggers a ranking boost. That number has no Amazon source. Not a help page, not a blog post, not an announcement. We have chased it, and it traces back to blogs quoting other blogs.
Price the product to sell. Watch conversion and the featured offer. Do not tune a listing to a percentage band that Amazon never wrote down.
Amazon caps keyword stuffing instead of penalising it
Amazon publishes no named stuffing penalty. No demotion, no suppression flag, no scoring rule for repeated words. Guides that describe one are describing something they cannot cite.
What Amazon does publish is three hard caps.
- A title may not repeat the same word more than twice, with prepositions, articles and conjunctions excepted.
- Titles stop at 75 characters, so there is little room to repeat anything.
- Search term entries over the byte limit get rejected outright rather than trimmed.
That framing beats an invented penalty. You are not risking a mystery downgrade. You are running out of space, and Amazon enforces it.
Alexa for Shopping, formerly Rufus
The assistant changed name this year. Amazon merged Rufus into Alexa on 13 May 2026 and the shopping assistant became Alexa for Shopping. Nearly every optimisation guide on the web still calls it Rufus, which tells you how recently those pages were checked.
The only inputs Amazon has ever named sit in the launch post of 1 February 2024. The assistant draws on “Amazon’s extensive product catalog, customer reviews, community Q&As, and information from across the web”, retrieved at answer time.
Amazon publishes no seller optimisation guidance for it. None. So reason from the four named inputs and label the rest as inference, which is what it is.
Inference one: clean attribute data in your catalogue gives retrieval something accurate to quote. Inference two: the questions in your community answers section shape what the assistant can say. Inference three: pages about your product elsewhere on the web sit inside the retrieval set. Test those ideas. Do not sell them as documented.
What to do this week
- Export the catalogue and sort titles by character count. Anything over 75 sits on Amazon’s rewrite list.
- Write Item Highlights for the top sellers first, inside 125 characters, using terms the shorter title dropped.
- Rebuild search terms as one entry under 250 bytes, lowercase, with no repeats of title words.
- Check that every main image runs at 1,600 pixels or more and fills 85 percent of the frame.
- With Brand Registry, open Search Query Performance and compare impression share against your keyword list.
Titles come first because Amazon will change them for you if you wait.
Frequently asked questions
Is A9 still Amazon’s ranking algorithm?
A9 was never documented as the ranking algorithm. A9.com was an Amazon subsidiary founded in 2003 that built search technology, and Amazon retired the site in 2019. The team became Amazon Search. No Amazon paper, help page or announcement has used A9 as the name of the product ranking system.
What is the A10 algorithm?
A10 has no Amazon source of any kind. No paper, no patent, no help article, no forum announcement mentions it. The term appeared in seller communities and spread because it sounded like a natural successor to A9. Treat any guide built on A10 mechanics as confident fiction.
What is Amazon COSMO?
COSMO is a commonsense knowledge graph system described in an Amazon Science paper at SIGMOD 2024. Large language models generate the knowledge, and classifiers trained on human scoring filter it. Amazon describes it as deployed in search applications such as search navigation. The reported gains come from the KDD Cup 2022 benchmark, not from live ranking.
How many characters can an Amazon title be in 2026?
Seventy five characters including spaces, in every category except media, effective 27 July 2026. Amazon’s Seller Forums announcement of 10 June 2026 states it directly. Titles still over the limit after that date get replaced with Amazon’s own recommendation, gradually. Amazon’s marketing blog still shows the older 200 character figure.
What is the Item Highlights field?
Item Highlights is a 125 character field introduced alongside the 75 character title cap. Amazon states that the content is searchable and appears with titles in search results and on product detail pages. It is the first place to move material, size and use case keywords that no longer fit inside a shortened title.
Do backend keywords still work on Amazon?
Yes. Amazon’s seller blog says keywords added to catalogue data stay invisible to customers but can still help a product rank for specific searches. The field is small, so spend it on spelling variants, abbreviations and terms that appear nowhere else on the listing. Repeating title words wastes the space.
Is the search terms limit 250 characters or 250 bytes?
Bytes. Amazon’s announcement text says the limit applies to total content across all generic keyword fields, a maximum of five attributes. The whole entry gets rejected on overflow. India runs 200 bytes and Japan 500. Accented and non-Latin characters consume more than one byte each, so plain lowercase text fits more terms.
Does lowering my price improve my Amazon ranking?
Amazon says only that adjusting your list price to stay competitive can improve product ranking and increase sales. That is directional and nothing more. The repeated claim that pricing within 5 to 12 percent of the market average triggers a boost has no Amazon source. No threshold has ever been published.
Does A+ Content help Amazon SEO?
Amazon describes A+ Content as rich text, images, video and comparison charts for detail pages, free to brands in Brand Registry. Amazon does not state that A+ Content text is indexed for search. Its documented value is conversion and comparison, and stronger conversion feeds the listing quality Amazon links to rankings.
Does Amazon PPC improve organic ranking?
Amazon publishes no statement that advertising lifts organic position. The honest version is indirect. Ads produce sales and reviews, and Amazon links listing quality and account health to search rankings. Anyone quoting a fixed organic lift from a spend level is quoting a blog. Our Amazon PPC guide covers the measurable part.
How do I check whether my listing is indexed for a keyword?
Search the exact phrase plus your ASIN in the Amazon search bar. If the listing returns, Amazon has indexed that phrase. If nothing returns, it has not. Brand Registry sellers get better evidence from Search Query Performance, which reports impressions and clicks against real customer queries.
Will Amazon rewrite my title if I do nothing?
Yes. Amazon states that titles still over 75 characters after 27 July 2026 get updated to its AI recommendation gradually. Brand owners receive 14 days to review, modify and approve those recommendations before they go live. The View enhancements area in Manage All Inventory is where you act first.
How do I optimise for Alexa for Shopping?
Amazon publishes no seller guidance for it. Work from the four inputs Amazon named for Rufus: the product catalogue, customer reviews, community questions and answers, and information from across the web. Clean attribute data and answered customer questions give retrieval something accurate to use. Everything past that is inference, not documentation.
How long does it take to rank on Amazon?
Amazon publishes no timeline, and neither do we. Indexing for a new term often shows within days. Position depends on sales velocity, conversion and category competition. Anyone quoting a fixed number of weeks is guessing. Measure your baseline first, then track query level data weekly.
Where to go next
Treat this page as a reference. Check any advice you read against the source column before you act on it. If you would rather hand the audit, the title rewrites and the backend rebuild to someone else, that is our Amazon SEO and listing optimisation service. We start with a free audit, and every file and login stays yours.
