Express Protocol SDK
One open-source SDK to mint, trade, and manage NFTs and real-world assets onchain — without touching Solidity. Built for the AI-agent era, with x402 as a first-class standard so autonomous agents pay and settle on their own.
import { createPandoraExpressSDK } from "pandora-express";
// wire up the SDK with a viem/web3 signer
const sdk = createPandoraExpressSDK({ signer, chainId: 8453 });
// 1 · mint an ERC-721 into the public collection
const { tokenId } = await sdk.erc721.mint({
tokenURI: "ipfs://…/asset.json",
royalty: 5, // % to the creator, forever
});
// 2 · list it for sale on the shared orderbook
await sdk.erc721.order.sellNFT({
tokenId,
price: "25.0", // USDC
});Token & payment standards
Deploy and manage any token type — and settle agent payments — through the same typed SDK. Express abstracts the contract calls so you ship features, not ABIs.
The classic non-fungible standard — one-of-one collectibles, art, and tickets. Mint, batch-mint, sell, buy, auction, and bid, in personal or public collections.
Fungible and non-fungible editions from a single contract — ideal for game items, passes, and semi-fungible drops. Full mint-to-auction lifecycle, same API surface.
The experimental hybrid: an NFT and its ERC-20 fraction move together. Transfer the token, the fungible units follow — native fractional ownership and liquidity.
A first-class payment standard for autonomous agents — settle agent-to-agent purchases over HTTP 402 in USDC. Quote, authorize, and clear on their own, no human checkout.
Everything to trade onchain
Express Protocol wraps a suite of audited smart contracts and libraries in a Software Development Kit — so any Web2 developer can build NFT and RWA applications without diving into the chain.
Mint single assets or thousands at once into a personal or public collection, each with creator royalties baked in.
mint()batchMint()burn()A complete trading lifecycle — fixed-price sales, buys, timed auctions and bids — all settling against a shared orderbook across every app on the protocol.
sellNFT()buy()auction()bid()A single royalty standard for protocol-minted and externally minted NFTs. Creators keep earning on every resale across all protocol applications.
setRoyalties()RoyaltiesSetMint into Pandora's public collection to go live instantly, or spin up your own personal collection contract for a fully branded storefront.
createCollection()publicpersonalPin metadata and media to decentralized storage out of the box — Express ships with Pinata integration and presigned uploads for your assets.
pinata.upload()ipfs://Query rich, multichain data on NFTs and their creators through one unified API — as an open-source storehouse for indexing and analytics.
index()unified APIx402 · payments for AI agents
Express Protocol treats x402 as a first-class standard — built on Coinbase's HTTP 402 stablecoin rail and sitting right alongside ERC-721, ERC-1155, and ERC-404. Point an agent at a listing and it can price, authorize, and settle the purchase autonomously — paying in USDC over the wire, no human checkout, no API keys to babysit.
import { createPandoraExpressSDK } from "pandora-express";
import { x402 } from "pandora-express/x402";
const sdk = createPandoraExpressSDK({
signer: agentWallet,
chainId: 8453, // Base
modules: [x402({ asset: "USDC" })],
});
// the agent buys — payment is handled inline
await sdk.erc721.buy({
tokenId,
paymentMethod: "x402", // HTTP 402 · USDC
});Modernized for 2026
Fully typed SDK with first-class viem support and modern async ergonomics.
Deploy to Base, Arbitrum, and Optimism — low-fee settlement where users are.
ERC-4337 smart accounts and gas sponsorship for frictionless agent flows.
MIT-licensed, community-driven, and audited — inspect every line on GitHub.
Guides
Step-by-step walkthroughs, straight from the Express Protocol docs — each one builds a working product on the SDK.
Stand up a full mint-list-buy marketplace with public collections and the shared orderbook.
Wire up timed auctions, bidding, bid execution, and withdrawals end to end.
Batch-mint a drop, pin assets to IPFS, and open sales with a few lines of SDK code.
Use ERC-1155 editions as event tickets, with royalties and resale baked in.
Start building
npm install to onchain in minutesInstall the package, plug in a signer, and mint your first asset. The docs cover every function across all four standards — ERC-721, ERC-1155, ERC-404, and x402 agent payments.
Open source
Express Protocol is open source end to end — the SDK, its documentation, and the smart contracts underneath. Inspect every line, open an issue, or ship a PR.
Built on Express Protocol
Real platforms that shipped on the Express Protocol SDK — marketplaces, games, and asset apps, all trading against the same shared orderbook.
FAQ
The essentials on Express Protocol, x402 agent payments, and shipping on the SDK.
x402 is a payment standard for autonomous agents, built on the HTTP 402 Payment Required status code. When an agent requests a paid resource, the server answers 402 with a price and terms; the agent signs a stablecoin (USDC) payment, re-sends it as a payment header, and receives a 200 OK with the asset. In Express Protocol, x402 is a first-class standard alongside ERC-721, ERC-1155, and ERC-404 — so agents can quote, pay, and settle onchain without a human at a checkout.
No. Express wraps a suite of audited smart contracts behind a fully typed TypeScript SDK. You plug in a viem/web3 signer and call methods like mint(), sellNFT(), and buy() — the SDK handles the ABIs, encoding, and onchain calls for you.
Four: ERC-721 (unique NFTs), ERC-1155 (multi-token editions), ERC-404 (fractional NFT/ERC-20 hybrids), and x402 (agent-to-agent payments). All four are reached through the same interface, so the API surface stays consistent as you move between them.
Express is rebuilt for today's onchain stack and targets low-fee L2s — Base, Arbitrum, and Optimism — with first-class viem support and ERC-4337 account abstraction for gasless, agent-friendly flows. x402 settlements clear in USDC on Base or Arbitrum.
Yes — end to end and MIT-licensed. The SDK ships as pandora-express on npm, and the SDK, its docs, and the smart contracts underneath are all public on GitHub. Inspect every line, open an issue, or send a PR.
Talk to us
Walk through the SDK, the x402 agent flow, and how to ship a marketplace or agent-commerce app on top of it — with the team that built it.