@realmint/sdk

TypeScript SDK for the Realmint API — list, buy, sell, and withdraw tokenized real-world assets. Non-custodial: you inject the signer, the SDK never holds keys. Gas is sponsored in USDC (no native gas needed), and funding is over x402.

npm install @realmint/sdk

You bring your own EVM signer (viem account or an EIP-1193 provider). For Solana sells you also bring a Solana signer. Node 18+ (native fetch).

Quick start

import { RealmintClient, signerFromViemAccount } from "@realmint/sdk";
import { privateKeyToAccount } from "viem/accounts";

const client = new RealmintClient({ apiKey: process.env.REALMINT_API_KEY! });

// The user's EVM account (the partner manages this key, not Realmint).
const account = privateKeyToAccount(userPrivateKey);
const sign = signerFromViemAccount(account);

List

const assets = await client.listAssets({ roots: true });
const paxg = await client.getAsset("paxg");
const score = await client.getScore("paxg");
const venues = await client.getRouteSupport("paxg");
const holdings = await client.getPortfolio(account.address);

Buy

buy() runs the whole lifecycle: create → prepare → sign the UserOp → submit to the bundler → execute → poll to completion. The user's smart account must already hold USDC (fund it with fundWithX402 first).

const intent = await client.buy(
  {
    asset_id: "paxg",
    source_token: "USDC",
    amount_in: 100,            // 100 USDC
    agent_wallet: account.address,
  },
  sign,
);
console.log(intent.status); // "completed"

Sell

EVM-deployed assets sell with zero signatures (the protocol executes the swap via a session key):

const sold = await client.sellEvm({
  asset_id: "paxg",
  source_token: "USDC",
  amount_in: 0.05,            // asset quantity to sell
  agent_wallet: account.address,
});

Solana-deployed assets take one Solana signature on the prepared wire:

import { SignSolanaWire } from "@realmint/sdk";

const signWire: SignSolanaWire = async (wireBase64) => {
  // co-sign the base64 V0 transaction with the user's Solana key, return base64
};
const sold = await client.sellSolana(
  { asset_id: "tslax", source_token: "USDC", amount_in: 1, agent_wallet: account.address },
  signWire,
);

Withdraw / send

Move funds out of your smart account to any address — gasless (paymaster-sponsored), one UserOp signature (same signer as buy). Works for both the keyless agent identity and Privy human identity.

const res = await client.withdraw(
  {
    chain_id: 1776,                       // Injective
    owner_eoa: account.address,
    token_address: "0xa00C59fF5a080D2b954d0c75e46E22a0c371235a", // native USDC
    recipient: "0x…",
    amount_raw: "4800000",                // 4.8 USDC (6 decimals)
  },
  signUserOpHash,
);
// res.mode === "bundler", res.user_op_hash set

Fund with x402

import { fundWithX402 } from "@realmint/sdk";

await fundWithX402(
  client,
  { owner_eoa: account.address, amount_usdc: 100 },
  async (paymentRequirements) => {
    // settle the requirements with your x402 client (e.g. the Coinbase x402 SDK
    // with a viem account on Base) and return the encoded X-PAYMENT header value
  },
);
// USDC is bridged to the user's Injective smart account, ready for buy().

Keyless agent auth

An autonomous agent holding only its own EVM key can authenticate without an API key: agentLogin exchanges an EOA signature for a bearer and returns a ready client.

import { agentLogin, fundWithX402, signerFromViemAccount } from "@realmint/sdk";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.AGENT_PRIVATE_KEY!);
const { client } = await agentLogin({
  ownerEoa: account.address,
  signMessage: (m) => account.signMessage({ message: m }),
});

await fundWithX402(client, { owner_eoa: account.address, amount_usdc: 5, asset_id: "tslax" }, payX402);
await client.buy(
  { asset_id: "tslax", source_token: "USDC", amount_in: 5, agent_wallet: account.address },
  signerFromViemAccount(account),
);

The bearer only authorizes quoting/creating intents for the EOA's own smart accounts; moving funds still requires the EOA's UserOp signature. See the reference agent.

Signing model

buy() signs an ERC-4337 UserOp v0.7 digest as an EIP-191 personal_sign over the 32-byte hash — that's what signerFromViemAccount / signerFromEip1193 produce. Don't use an EIP-712 typed sign or a raw ECDSA sign; the smart account validates the personal_sign form.

Lower-level methods (accountStatus, createIntent, prepareIntent, executeIntent, getIntent, reconcileIntent, waitForSettlement, submitUserOp) are exposed if you need to drive the lifecycle yourself.

See the full API reference at https://api.realmint.io/docs.