Building On-Chain API Key Management with Solana and Anchor

Building On-Chain API Key Management with Solana and Anchor When I started designing a decentralized API key management system on Solana, my first instinct was to reach for the usual off-chain tools — a Postgres table with hashed keys, role columns, a revocation flag. It works. Every SaaS company runs something like this. But the moment you need to let other programs verify access permissions without trusting a centralized server, the off-chain model falls apart. There is no composable way to prove, on-chain, that a given API consumer is authorized to call your service. So I built it on Solana with Anchor. What followed was an education in PDA design, account sizing discipline, and the surprising elegance of putting access control directly in the ledger state. The Problem: Why On-Chain Keys? Off-chain API keys have a single point of failure: your database. Compromise the database, rotate every key, notify every customer. The whole lifecycle — issuance, rotation, revocation, permission