The problem it solves

When you're building or testing a pay-per-request API with MPP TestKit, you're juggling a few moving parts at once:

mppFetch auto-creates a wallet, airdrops SOL, intercepts the 402, pays, and retries

createTestServer auto-generates a recipient keypair

mpp.charge({ amount: "0.001" }) gates a route and charges that amount per verified request