Sustain

A micropayment mechanism where holding a button streams USDC to creators on Tempo at $0.005/second. Built for the Tempo x Canteen Hackathon (Consumer Payments track).

Demo

sustain.tortoise.studio

How It Works

• Press and hold → a USDC payment stream opens on Tempo, flowing directly to the artist
• Release → the stream closes, payment settles instantly
• Quick tap → sends a $0.005 minimum payment
• Duration = amount → 3 seconds = $0.015

No amount selection, no confirmation screen, no crypto terminology. Privy handles auth with passkeys or social login. The demo plays a real track from Tortoise, an onchain independent music platform.

While built around music, the gesture maps naturally to any medium with a temporal dimension — podcasts, video, livestreams.

Why Tempo

This only works because Tempo provides two things no other chain does simultaneously:

• Sub-cent gas fees — a $0.003 payment makes economic sense
• Stablecoin-denominated gas — users only think in dollars, never crypto

Architecture

• Smart Contract — StreamPayment.sol deployed on Tempo Testnet (Moderato). Manages escrowed USDC, releases per-second based on block timestamps.
• Frontend — Next.js, Privy SDK for wallet auth, real-time payment ticker
• Music Data — Catalog and audio from Tortoise (Farcaster-native music platform)
• Faucet — Auto-funds demo users with AlphaUSD on login via test wallet

Contract Address

0xff3FB2A2d1Fb0eb20EBEE6c4906cCC6A7377a23b (View on Explorer)

Tech Stack

• Next.js / React / TypeScript
• Solidity (StreamPayment.sol)
• Privy (authentication + embedded wallets)
• Tempo Testnet (Moderato) — Chain ID 42431
• AlphaUSD (TIP-20) — 0x20c0000000000000000000000000000000000001

Local Development

git clone <repo-url>
cd sustain
npm install
cp .env.example .env.local
# Add NEXT_PUBLIC_PRIVY_APP_ID, PRIVY_APP_SECRET, FAUCET_PRIVATE_KEY
npm run dev

Built By

Matt Lee — Full-stack developer, founder of Tortoise. React, TypeScript, Solidity.

• mattlee.world
• github.com/mtple