The game’s save system is surprisingly transparent. You can export your save, paste it into a decoder/editor, tweak the numbers, re-encode it, and import it back.
Whether you are a purist who clicks every cookie manually or a hacker who sets Game.cookies = Infinity within the first five minutes, Cookie Clicker welcomes you. Now go forth, edit that save, and let the cookies rain from the heavens.
The most obvious edit. Players often give themselves a "Sextillion" cookies or edit their Prestige Level directly. This bypasses the need to ascend repeatedly. You can also edit the "Heavenly Chips" spent vs. unspent to unlock every heavenly upgrade instantly.