Solana Subscription Smart Contract—Ship in Days

Allowance vs. Escrow: Why This Matters Solana subscription systems live on a spectrum. Full escrow requires users to deposit tokens upfront into your contract's vault, safe, but forces capital lockup and creates smart contract risk concentration. Allowance-based subscriptions flip this: users approve you to pull a fixed amount periodically, you charge only when renewing, and their tokens stay in their wallet until withdrawal. We chose allowance because it mirrors Ethereum's ERC20 approve pattern that developers already understand, reduces TVL risk, and cuts integration friction. Users see smaller permissions windows instead of handing you custody of their entire subscription balance. The tradeoff: you need reliable renewal logic. If your renewal service lapses, subscriptions lapse. Solution in this boilerplate: deterministic grace periods and re-authorization checks that prevent silent failures.