Trustline onboarding protocol and SDK for Stellar. Bundles trustline creation and authorization into a single on-chain transaction (CAP-73 + Soroban), enabling wallets and exchanges to onboard users to any Stellar asset — including regulated AUTH_REQUIRED tokens — with one wallet signature. Ships a TypeScript SDK (@theaha/authline), Soroban router + authorizer contracts, a self-hostable relayer, and a multi-asset activation dApp at authline.io.