TL;DR
Mint authority is the wallet or program that has permission to create (mint) new tokens, increasing the total supply. If not revoked, the authority holder can inflate supply at any time.
When an SPL token is created, the creator is assigned as the mint authority by default. This gives them the power to mint additional tokens at any time, effectively diluting all existing holders. For a 1 billion supply token, a creator with mint authority could mint another billion tokens and dump them on the market, halving everyone’s value instantly.
Revoking mint authority permanently removes the ability to create new tokens. It’s a one-way action — once revoked, no one can ever mint more. Most legitimate memecoins revoke mint authority shortly after launch. Pump.fun automatically revokes mint authority when a token graduates, which is one reason graduated tokens are considered safer.
Token Scanner and block explorers like Solscan show whether mint authority is active or revoked. An active mint authority is one of the most critical red flags for any token. Never invest significant amounts in a token with active mint authority unless it’s a well-known protocol that needs it for legitimate purposes (like staking reward distribution).