Keyword field (App Store)

• The field accepts up to 100 bytes. The App Store Connect reference counts bytes, not characters, so Latin letters cost one byte each and many non-Latin characters cost more.
• Separate terms with commas and no spaces. Spaces are allowed inside a multi-word phrase.
• Each keyword must be longer than two characters.
• Keywords are required and can be localized.
• Do not repeat the app name or company name, and do not use names of other apps or companies.
• Apple advises not to repeat words from the name, subtitle or category.
• To save space, avoid plurals of words already included, generic terms such as "app" or "game", and filler words such as "the" and "to".

For a hypothetical habit tracker, this list is 54 bytes: routine,goals,daily,planner,reminder,checklist,morning. The same app in Japanese might use 習慣化,タスク管理,目標設定, which is 14 characters but 38 bytes, because each Japanese character takes three bytes in UTF-8. A Japanese list therefore holds far fewer terms than an English one.

• Adding spaces after commas. Every space is a wasted byte.
• Repeating words that already sit in the name, which uses space for no extra effect.
• Using the field as a place for branded keywords of competitors, which Apple prohibits.

Run your list through the keyword field checker or let the keyword field packer arrange it. The full method is in the keyword field guide.

The field is one part of ASO; the primary category is also indexed, so you do not need its words here.

Filler is explained under generic keywords, and counting under byte limit.