Mint authority and freeze authority

Every token on Solana is defined by a mint account. Two fields in it decide who keeps control after launch:

• Mint authority: the address that can create new tokens with the MintTo instruction, increasing the supply.
• Freeze authority: the address that can freeze any holder's token account. A frozen account can't send, receive or burn that token until the same authority thaws it.

Either field can be empty. An empty mint authority means the supply is fixed; an empty freeze authority means no one can freeze a balance.

Revoking is permanent

An authority is changed with SetAuthority, signed by the current holder. Setting it to nothing is a one-way step: with no authority left, no one can sign to set it again.

Real examples

Token	Mint authority	Freeze authority	What it means
USDC	set	set	The issuer mints and redeems as dollars move in and out, and can freeze balances, as a regulated stablecoin must.
PYTH	revoked	none	The supply can never grow, and no one can freeze a holder.

Neither setup is "safe" or "unsafe" on its own. A stablecoin needs both authorities to work, but for a token that says its supply is fixed, a live mint authority contradicts the claim.

How to check a token

Open any token page here, for example USDC. The Authorities section reads both fields from the chain and names the address that holds each one.