Elmatador Reli@Elmatador

PayStream is a pay-per-word AI chat application that demonstrates the Agentic Economy thesis: machines paying machines in real time, with sub-cent transactions no traditional payment rail can support. Instead of a flat $20/month ChatGPT subscription, users pay $0.0001 USDC for each word the AI writes. Every word triggers a real Circle Nanopayment on Arc Testnet via an EIP-3009 authorization signed by a Circle Developer-Controlled Wallet. The settlement flow is continuous: as tokens stream from the LLM, value flows on-chain. Stop the response mid-stream and the payments stop with it. A single chat response typically produces 100+ on-chain authorizations, batched by Circle Gateway into multiple settlements visible on the Arc Block Explorer. Key technical contribution: a custom W3S to BatchEvmScheme adapter that bridges Circle's secure-key-custody API with the x402 batching SDK that expects raw private keys. This lets per-user Circle wallets sign EIP-3009 authorizations without ever exposing the key. Built end-to-end during the hackathon: Next.js 14 frontend, Anthropic Claude Haiku for the AI, Circle Nanopayments + Developer-Controlled Wallets for payments, Arc Testnet for settlement.

In this hybrid hackathon powered by Arc and Circle, developers will build the next generation of Agentic economic applications using Circle’s Nanopayments infrastructure with settlement on Arc in USDC. For the first time, high-frequency, usage-based transactions between users, APIs, and AI agents can operate without gas overhead eroding margin. Arc provides stablecoin-native settlement with predictable, dollar-denominated USDC fees and deterministic, sub-second finality — enabling real-time coordination and economically viable per-action pricing at scale. 📅 April 20 – 26, 2026 • Apr 20 – 25 (Online): Submit projects by Apr 25. • Apr 25 (On-site Build – SF, CA): Teams refine projects. • Apr 26 (On-site Demos & Awards – SF, CA): Live pitches & winners announced. Get guidance from Arc and Circle experts through on-site support. 📍 On-site Venue (April 25-26): MindsDB SF AI Collective 3154 17th St, San Francisco, California, USA 🤝 Go solo or team up, it's your flow. 🏆 Compete for a $15,000+ Prize Pool. 📍 Please note: If approved for the on-site experience, you’ll also have the opportunity to showcase your project live. Travel and accommodation will not be covered. 🧑🏻‍💻 Secure your spot now – sign up before the Kick-Off Stream!