Mint

Describes a token — its authority, total supply, decimals, and optional freeze authority. USDC, USDT, and wrapped SOL all have Mint accounts.

Token Program 82 bytes

Sample: USDC Mint

(cached; refreshes hourly · mainnet only)

Mint Authority Option Mint Authority Supply Decimals Is Initialized Freeze Authority Option Freeze Authority

	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
0000	01	00	00	00	98	fe	86	e8	8d	9b	e2	ea	8b	c1	cc	a4
0010	87	8b	29	88	c2	40	f5	2b	84	24	bf	b4	0e	d1	a2	dd
0020	cb	5e	19	9b	59	d4	55	ff	c6	1c	1e	00	06	01	01	00
0030	00	00	62	70	aa	8a	59	c5	94	05	b4	52	86	c8	67	72
0040	e6	cd	12	6e	9b	8a	5d	3a	38	53	6d	37	f7	b4	14	e8
0050	b6	67

View full hex

What it is

An SPL Mint account defines a fungible token on Solana — its authority, total supply, decimals, and optional freeze authority. USDC, USDT, and wrapped SOL are all defined by Mint accounts.

Why it exists

Solana doesn’t ship a built-in token primitive. The SPL Token program treats every fungible token the same way: each token has exactly one Mint account holding the canonical metadata, and many Token Accounts holding individual balances. This separation is what lets the same token live in millions of wallets without re-storing the metadata each time.

Byte layout

Offset	Length	Field	Type	Notes
0	36	`mint_authority`	`COption<Pubkey>`	4-byte tag (`0` = None, `1` = Some) + 32-byte pubkey. When None, minting is permanently locked.
36	8	`supply`	`u64` LE	Total atomic units in circulation. Divide by `10^decimals` for human-readable amount.
44	1	`decimals`	`u8`	Exponent — e.g., USDC’s `6` means 1 USDC = 10⁶ atomic units.
45	1	`is_initialized`	`bool`	`1` once initialized; uninitialized Mints are unusable.
46	36	`freeze_authority`	`COption<Pubkey>`	4-byte tag + 32-byte pubkey. When Some, can freeze any Token Account holding this mint.

Total: 82 bytes.

Where you see it

You encounter a Mint anytime you read the mint field of a Token Account, call getMint over RPC, or look up an asset on Jupiter, a wallet UI, or an explorer.

Common gotchas

The COption tag is 4 bytes, not 1. SPL Token uses a 4-byte tag in front of each optional pubkey to preserve struct alignment for Pack (36 = 4 + 32). This is different from Borsh’s Option, which uses a 1-byte tag. Token-2022 follows the same SPL convention.
decimals is an exponent, not a digit count. A decimals of 9 means amounts are divided by 10⁹, not “displays 9 digits.”
mint_authority: None is permanent. Once an authority is removed (SetAuthority → None), nothing can re-enable minting. Many tokens lock minting after the initial issuance for trust.

Sources

SPL Token Mint struct (program/src/state.rs)