Does it convert hiragana to katakana?

No — NFKC does not change kana type (half-width kana does become full-width). Use romaji/furigana for readings.

Full-width / NFKC normalization API

NFKC-based text normalization that absorbs Japanese form-input variants before they pollute your database, with trim / whitespace-collapse options.

Method	Path
`GET`	`/api/v1/normalize`

curl "https://formfit.dev/api/v1/normalize?text=Ａ１２３ｶﾞ" \
  -H "Authorization: Bearer YOUR_API_KEY"

{"normalized":"A123ガ","changed":true}

Does it convert hiragana to katakana?: No — NFKC does not change kana type (half-width kana does become full-width). Use romaji/furigana for readings.