Amazon backend keywords: how to fill search terms

Every Amazon listing has visible text, such as the title, bullet points and description, and hidden fields that only Amazon reads. The most important hidden field for search is Search Terms, labelled Generic Keyword on the Product Details tab when you edit a listing in Seller Central, and generic_keywords in a flat file. Amazon's own seller blog calls it a spillover for keywords that do not fit naturally on the page.

Shoppers never see these words, so they are the place for terms that would make your title clumsy: synonyms, abbreviations, alternate names and spelling variations. They are not a place for anything Amazon prohibits elsewhere, and they do not replace a clear title and bullets. The words a shopper reads still have to describe the product.

Amazon staff in the Seller Forums put the limit at 250 bytes and stress that bytes are different from characters. Plain letters a to z and digits 0 to 9 count one byte each, so for English text without accents the two numbers match. Accented letters and some symbols take two or three bytes, so a German or French line fills up sooner than its character count suggests.

Going over matters. An Amazon staff post says a Search Terms value over the limit is completely ignored by Amazon Search, and Amazon's help text, as quoted by sellers, says the whole entry is rejected. Either way you lose every word in the field, not just the last few. The help pages render only after login, so the figures below for other marketplaces and byte weights come from that help text as quoted in the Seller Forums. Check the help page for your own marketplace before you rely on them.

Amazon's announcement on optimizing search terms lists what belongs in the field and what is prohibited, and warns that prohibited keywords may lead to ASIN suppression and action against your account. Amazon staff tips add the formatting rules: separate words with spaces, skip punctuation and stop words, and do not repeat information already in the title or brand.

Good backend keywords are the words real shoppers type that your visible listing does not already contain. Amazon's seller blog points to a few free sources; start with them before you pay for a keyword tool.

Work from your research list to one line. The order of the words matters less than which words make it in, so spend the bytes on terms that are relevant and not yet anywhere on the listing.

Most problems with search terms come from treating the field as a dump for every keyword you found. These are the mistakes worth checking for first.

Before you paste the line into Seller Central or a flat file, run three checks. First the length: count characters, then add one for each accented letter and two for each euro sign, or paste the line into any UTF-8 byte counter. Stay a little under the limit rather than exactly on it. Second, compare the line with the title, bullets and brand and remove overlaps. Third, read it once for anything on the prohibited list.

For a catalog, do this in a spreadsheet with one row per product and marketplace, so you can sort by length and see which listings share the same line. Your bullet points carry keywords too, in visible form; the Amazon bullet points guide covers how to write them without stuffing.

Backend keywords are product data like any other field: they belong to one product, they differ per language and they go stale when the title changes. Keeping them next to the title and bullets makes the overlap check easier and stops the line from living only in Seller Central.