What is the App Store keyword field?
The keyword field is a private, comma-separated list in App Store Connect that helps Apple match an app to relevant searches. It is not visible on your product page. Choose words that describe real functionality and the audience you serve; a keyword is a candidate for discovery, not a promise that your app will rank.
Apple’s platform version reference specifies a limit of 100 bytes. Its product-page guidance describes 100 characters. ASCII letters and commas use one UTF-8 byte each, but accented letters, emoji, and many other scripts can use more. Check App Store Connect’s validation for the actual localization before submitting.
How to format keywords
Separate entries with commas and avoid spaces after commas. Spaces inside a multiword phrase are allowed: meditation,sleep,breathing exercise is a format example, not a recommendation for every wellness app.
Apple advises against repeating words and variants unnecessarily, including names already represented in your app name or category. Do not insert competing app names, irrelevant terms, or unauthorized trademarks. Review Apple’s guidance when preparing a submission.
Count bytes before publishing
For a local check, paste a draft into a tool that reports UTF-8 bytes, not just visible characters. For example, cafe uses four UTF-8 bytes; café uses five when its accented character is encoded as a single code point. Some visually identical strings use different Unicode representations, so measure the exact text you plan to submit.
Start with the languages and terminology your customers actually use. Leave room when needed instead of squeezing in unrelated words. Test each localization separately, especially when its writing system uses more bytes per character.
Choose words with a reason
List what your app does, the problems it solves, and alternative ways customers describe those problems. Inspect current search results in the relevant country: if a phrase mostly returns apps for a different job, it may be a poor fit even if a research tool estimates high demand.
Keep a separate list of full search phrases to monitor. The field is a publishing input; the list is your research record. Use ASO Engine’s keyword research workspace to compare estimated scores and results, and read the metadata checklist before changing your listing.