Build your Amazon backend search terms from the real searches in your niche: the most searched words your listing does not have yet, packed into 249 bytes, with your current search terms checked against Amazon's rules.
Backend keywords are the words in the Search terms field of an Amazon listing, the field Seller Central calls the Generic keyword field. Shoppers never see them, but Amazon search reads them, so your listing can be found for words that would crowd the title or read badly in a bullet: other names for the product, other spellings, the Spanish words many US buyers type, the people it is for. This Amazon backend keywords generator fills that field from real Amazon search data. Type your niche, add your title and bullets if you have them, and it writes the words buyers search that your listing does not have yet, most searched first.
Amazon caps the field in bytes, not characters. It must stay under 250 bytes, and Seller Central stops taking words at the limit. Spaces and punctuation are not counted, so separate the words with spaces and leave out the commas. Plain letters and digits take one byte each; a letter with an accent, such as the ñ in "niña", takes two, which adds up when you use Spanish words. The tool counts the same way, keeps the field at 249 bytes or less, and its byte meter moves as you add or take out words.
Amazon's help page warns that breaking these rules may get your ASIN suppressed. The tool leaves all of these out, and when you paste your current search terms it checks them and names the words to remove.
Every word comes from the search terms Amazon tracks for your niche in Opportunity Explorer. Each word is ranked by the searches of the terms that contain it, so a word that shows up in many busy searches comes first. Amazon search does not match parts of words: a shopper who types "lockable jewelry chest" finds only listings that have all three words somewhere. That is why a word like "lockable" earns its place even with modest volume. Untick any word that does not describe your product and the field fills the room with the next word that fits.
Platinum keywords were an old, separate keyword field that only sellers in Amazon's Platinum program could fill. A regular listing does not have it, so the field to work on is the Generic keyword field, which is the one this tool writes.
To see every search term in a niche with its searches, sales and conversion, open it in the Amazon keyword research tool. To check your title, item highlights and bullets against Amazon's rules as well, run the whole listing through the Amazon listing optimization tool.
Type your niche the way a shopper searches, such as "jewelry boxes for women", or pick one of Amazon's niches from the list as you type. If you have a listing, open Your listing and paste its title, item highlights and bullets, plus your current search terms. The tool then shows:
The words come from Amazon Opportunity Explorer, refreshed weekly for Amazon.com. Each word is kept in one form, singular or plural. Words your listing already has in either form, small words such as "for" and "with", repeats and subjective or temporary words are left out before the packing starts. You can still tick one of them back in; a subjective word then gets a short note.
Each run uses one of your daily lookups, which every research tool on the site shares: 3 a day without an account, 10 with a free account and more on paid plans. The tool has no AI part, so it never uses credits. Running the same niche with the same listing again within 6 hours opens from memory and costs nothing.