Superjam

SuperJam is a super-app host for the open web — a place to make and play little apps, with money, that anyone can use. We call them jams.

You describe a jam in a single sentence — "a tip jar with a leaderboard," "a daily trivia game," "a doodle-guessing duel" — and an AI builder agent designs, builds, and deploys it live in under a minute. No code, no terminals, no build logs: you just watch your jam come together, and then it's online.

You discover jams in a TikTok-style vertical feed, but with a twist — tap Play and the jam runs live, right there in the feed. It's a real, working app, not a video.

Everything crypto is invisible. You sign in with email and a wallet appears with it — no seed phrase, no extension. You claim your name and it's yours on-chain forever (you.superjam.eth), and every jam you make hangs under it (tipjar.you.superjam.eth). Jams can hold real money, run real on-chain games, and pay out — but to a player it just feels like a toy that happens to have a coin slot.

Under the hood, an agent economy does the work: real AI builder agents — each with its own wallet, an on-chain ERC-8004 identity, and a USDC reputation stake on the line — build your jam, some backed by a verified human via World ID. Payments settle on Circle's Arc chain, can be made fully private via Unlink, and your own coding agent can even commission a jam for you over MCP.

Architecture. A Bun + Turborepo monorepo. The consumer app (apps/web) is Next.js on Vercel; an API server runs on Railway; smart contracts live in a Foundry package (packages/contracts); and an AI builder agent turns prompts into deployed apps. Shared code — the injected SDK, on-chain helpers, the DB layer, and per-environment service URLs — lives in packages/* (sdk, onchain, db, shared).

Jams are sandboxed mini-apps. Each jam runs in a sandboxed iframe with an SDK injected over postMessage, giving it a uniform surface: wallet, profile, key-value storage, and shared cross-jam data. The host owns every sensitive action — a jam can request a payment, but the wallet and confirmation live in the host, so "jams never touch your wallet." Generated jams ship with our "Toybox" theme so they look host-native out of the box.

The make pipeline. A prompt becomes a plan, the user tweaks it conversationally, then a builder agent generates the code and deploys it — Next-on-Vercel for full apps, standalone Vite bundles for games. Publishing is gated by World ID (humanness) and a small pay-to-publish fee in USDC.

Two chains. Circle's Arc is the money chain (settlement + USDC); Sepolia L1 carries identity (ERC-8004 + ENS v2) and is the CCTP source. One APP_ENV drives per-environment URLs.

Partner tech, and what each bought us:

• Dynamic — email-login embedded EVM wallets (the "wallet appears with you, no seed phrase" magic), plus TSS-MPC server wallets that let builder agents sign autonomously, and delegation that powers agent-hires-agent over MCP.
• World ID — idkit v4 with a managed RP (the RP self-signs rp_context); used both as the anti-Sybil gate to keep publishing and to mark builder agents as human-backed.
• Circle — Arc for settlement, CCTP for cross-chain USDC (e.g. funding a stake from Sepolia), and gasless EIP-3009 transfers relayed by the server for tips and in-game payments.
• Unlink — a shielded private-payment rail so an agent can pay for work without leaking its balance or transaction graph.
• ERC-8004 + ENS v2 — every builder agent (and every user) gets a real, human-readable on-chain identity; a self-contained SuperjamRegistry resolves those names in standard ENS tooling.
• x402 — the pay-to-publish build fee is charged over the private rail; free when the user is World-verified and the builder is AgentBook-registered.
• MCP — a SuperJam MCP server lets a coding agent (e.g. Claude Code) hire a builder as you via a scoped sjat_ PAT + Dynamic delegation, turning "build me an app" into one delegated transaction.

Notably hacky bits:

• The Unlink rail couldn't bootstrap from Dynamic delegation (WaaS key-shares threw No wallet provider found), so we bootstrap the shielded account from a one-time browser signature of a canonical message and replay it server-side — one seam then covers payments, build fees, and tips.
• Nested ENS names (<slug>.<user>.superjam.eth) work via an ENSIP-10 wildcard resolver: our registry is its own IExtendedResolver (it has no setSubregistry), yet still resolves through canonical ENS tooling.
• On-chain game writes are operator-relayed and gasless — the Arc operator must equal the API server wallet or the writes revert.
• The web app is forced to build with webpack, not Turbopack, because the Dynamic React SDK needs it.