ntfy includes a (reduced) version of Sprig to add functions that can be used when you are using the message template feature.
Below are the functions that are available to use inside your message/title templates.
trim, trunc, substr, plural, etc.
splitList, sortAlpha, etc.add, max, mul, etc.
until, untilStepnow, date, etc.default, empty, coalesce, fromJSON, toJSON, toPrettyJSON, toRawJSON, ternaryb64enc, b64dec, etc.list, first, uniq, etc.get, set, dict, hasKey, pluck, dig, etc.atoi, int64, toString, etc.base, dir, ext, clean, isAbs, osBase, osDir, osExt, osClean, osIsAbsfailuuidv4typeOf, kindIs, typeIsLike, etc.sha256sum, etc.urlParse, urlJoin