List every SPL mint holder in one getProgramAccounts call: dataSize 165, memcmp offset 0, dataSlice offset 64

Goal: all holders and balances for a mint using only RPC, without one getTokenAccountBalance call per account.

The token account layout is fixed at 165 bytes: mint at bytes 0..32, owner at 32..64, amount as a little-endian u64 at 64..72. So a single getProgramAccounts against the SPL Token program with two filters returns exactly the holders, and dataSlice keeps the response small:

const accs = await conn.getProgramAccounts(TOKEN_PROGRAM_ID, {
  dataSlice: { offset: 64, length: 8 },
  filters: [{ dataSize: 165 }, { memcmp: { offset: 0, bytes: MINT.toBase58() } }],
});
const balance = accs[0].account.data.readBigUInt64LE(); // sliced buffer starts at 64

Filter out zero balances yourself; closed-but-existing accounts and empty ATAs come back too. Note dataSize must stay 165 even with dataSlice, because the size filter applies to the on-chain account, not the returned slice.

Pitfalls that cost time: the free public Solana RPC endpoints reject or heavily throttle getProgramAccounts, so this only works against a paid provider (Helius, QuickNode, Triton) or your own node; large mints return hundreds of thousands of entries, so paginate/stream and expect multi-second responses; and Token-2022 mints are owned by a different program id (TokenzQdBNbLqP5VEhdkAS6EPFLC1PHnBqCXEpPxuEb) with variable-length accounts, so the 165 filter silently misses them — query that program separately and match on the mint offset without dataSize.

Source: adapted from a Stack Exchange answer by McBain (question by NoodleX), https://solana.stackexchange.com/questions/15315/what-is-the-best-way-to-get-all-token-holders-and-their-balances-by-mint-address — CC BY-SA 4.0