Solana Token-2022 NonTransferable or Sui Closed-Loop Token — minted to wallets, never transferred between them. Identity, attendance, KYC attestation, reputation.
Soulbound tokens are how on-chain identity stays on-chain. Once minted to a wallet, the token can never move — making it useful for credentials, attendance proofs, KYC attestations, and reputation systems where transferability would let users game the assignment. This preset is the simplest possible SBT on either chain: Solana's Token-2022 NonTransferable extension or Sui's Closed-Loop Token with no transfer rule registered on the TokenPolicy.
On Solana, the NonTransferable extension is a single bit on the mint account — the SPL Token-2022 program enforces it at the protocol level, no custom logic to audit. On Sui, `sui::token::Token<T>` is declared with only the `key` ability (no `store`), so `transfer::public_transfer` is rejected at compile time and every move requires a TokenPolicy rule — which we don't register. Bypass is structurally impossible on both chains.
EVM has no protocol-level non-transferable primitive — every implementation overrides the `_update` hook on the ERC-20 base to revert, which works but is not as clean (the revert path is auditable code, not protocol enforcement). Solana and Sui both expose first-class soulbound semantics, so we ship there first. An EVM variant is tracked for when the use case justifies a per-chain implementation.
Yes on both chains. On Solana, the NonTransferable extension blocks transfers between wallets but not burns — the mint authority can revoke a credential via the standard SPL Token Burn instruction. On Sui, the deployer holds the TreasuryCap and can burn via `sui::token::burn` (the Closed-Loop policy applies to user-initiated transfers, not issuer burns).
Identity / SBT is the maximally-restrictive form — no transfers, ever, by anyone. Loyalty (Sui-only) allows transfers but only to addresses on the issuer-managed allowlist (your merchants, partner wallets, operator accounts). Pick Identity for credentials and attendance proofs; pick Loyalty for closed-loop points programmes where holders need to spend balances within the merchant network.