Amazon Backend Keyword Limits and Rules

Policy Details

Amazon's backend keyword field (Search Terms in the Keywords tab of Edit Listing) has a limit of 250 bytes. Note that this is bytes, not characters — some special characters and non-ASCII letters count as 2-4 bytes each. Using only standard English letters and numbers, 250 bytes equals 250 characters. Format rules: separate each keyword term with a space (not a comma, semicolon, or other punctuation). Amazon indexes individual words from the space-separated list. Using commas adds comma characters that count against your byte budget without adding indexing value. Do not put quotation marks around phrases — Amazon automatically indexes phrase combinations from your word list. One instance of each word is sufficient — Amazon will not rank you higher for a word that appears twice in your backend keywords. Since the title, bullets, and description are also indexed, you should focus your 250-byte backend keyword budget exclusively on terms that do not appear anywhere in your visible listing content: synonyms ("couch" if your title says "sofa"), alternate spellings ("color" and "colour"), related search terms, and use-case keywords that are relevant but too long for visible copy. Check your search term report in Seller Central Business Reports quarterly to find new terms that should be added to your backend keywords.