Basemarket API Reference

Full API reference for Basemarket market data, trade operations, signing flow, and dashboard data.

All monetary values are micro-USDC strings (6 decimals). Public market and health endpoints are open; wallet-scoped trade endpoints enforce wallet and access checks.

Base API URL: https://api.basemarket.fun

Authentication & Signing

Buy orders use USDC EIP-3009 signatures. Sell orders use claim-transfer typed signatures against the orderbook contract.

TypeScript: build buy authorization

TypeScript (ethers v6)

import { ethers } from "ethers";

const domain = {
  name: "USD Coin",
  version: "2",
  chainId: 8453,
  verifyingContract: USDC_ADDRESS,
};

const types = {
  TransferWithAuthorization: [
    { name: "from", type: "address" },
    { name: "to", type: "address" },
    { name: "value", type: "uint256" },
    { name: "validAfter", type: "uint256" },
    { name: "validBefore", type: "uint256" },
    { name: "nonce", type: "bytes32" },
  ],
};

const message = {
  from: maker,
  to: ORDERBOOK_ADDRESS,
  value: usdcAmountMicro,
  validAfter: 0,
  validBefore: Math.floor(Date.now() / 1000) + 300,
  nonce: ethers.hexlify(ethers.randomBytes(32)),
};

const signature = await signer.signTypedData(domain, types, message);

Python: build buy authorization

Python (eth-account)

from eth_account import Account
from eth_account.messages import encode_typed_data
import secrets, time

typed_data = {
  "types": {
    "EIP712Domain": [
      {"name":"name","type":"string"},
      {"name":"version","type":"string"},
      {"name":"chainId","type":"uint256"},
      {"name":"verifyingContract","type":"address"},
    ],
    "TransferWithAuthorization": [
      {"name":"from","type":"address"},
      {"name":"to","type":"address"},
      {"name":"value","type":"uint256"},
      {"name":"validAfter","type":"uint256"},
      {"name":"validBefore","type":"uint256"},
      {"name":"nonce","type":"bytes32"},
    ],
  },
  "primaryType": "TransferWithAuthorization",
  "domain": {
    "name": "USD Coin",
    "version": "2",
    "chainId": 8453,
    "verifyingContract": USDC_ADDRESS,
  },
  "message": {
    "from": MAKER,
    "to": ORDERBOOK_ADDRESS,
    "value": int(USDC_AMOUNT_MICRO),
    "validAfter": 0,
    "validBefore": int(time.time()) + 300,
    "nonce": "0x" + secrets.token_hex(32),
  },
}

msg = encode_typed_data(full_message=typed_data)
sig = Account.sign_message(msg, PRIVATE_KEY).signature.hex()

Market API

GET/api/market/snapshot

Returns current event/market context, orderbooks, and live BTC metadata.

Request

curl https://api.basemarket.fun/api/market/snapshot

Live Response (sample)

{
  "current": {
    "event": { "id": "event-389", "ticker": "BTC5M-389", "active": true },
    "market": { "id": "round-389", "question": "Will BTC close up in this 5 minute window?" },
    "tokenIds": ["YES", "NO"],
    "orderbook": { "up": { "asset_id": "YES" }, "down": { "asset_id": "NO" } }
  },
  "events": [],
  "btcPrice": "…",
  "priceToBeat": "…"
}

Click "Try it" to fetch live JSON.

GET/api/market/orderbook?outcome=YES

Request

curl "https://api.basemarket.fun/api/market/orderbook?outcome=YES"

Live Response

{
  "market": "basemarket",
  "asset_id": "YES",
  "timestamp": "2026-02-28T17:35:55.296Z",
  "bids": [],
  "asks": [{ "price": "0.500000", "size": "5000000" }],
  "min_order_size": "1",
  "tick_size": "0.0001"
}

Click "Try it" to fetch live JSON.

GET/api/market/events

Request

curl https://api.basemarket.fun/api/market/events

Live Response (sample)

{
  "events": [
    {
      "type": "SELL_PLACED",
      "orderId": 790,
      "outcome": "NO",
      "amountMicro": "5000000",
      "priceMicro": "500000",
      "roundId": 389
    }
  ],
  "rounds": [389, 388],
  "hasMore": true,
  "nextCursorRoundId": 388
}

Click "Try it" to fetch live JSON.

Trade API

POST/api/trade/buy

Places a buy using USDC transfer authorization (EIP-3009 typed signature).

Request Body (example)

{
  "maker": "0xYourWallet",
  "outcome": "YES",
  "isMarket": false,
  "limitPrice": "500000",
  "usdcAmount": "5000000",
  "auth": {
    "validAfter": "0",
    "validBefore": "1772301000",
    "nonce": "0x...",
    "signature": "0x..."
  }
}

POST/api/trade/sell

Places a sell using claim transfer authorization (BasemarketClaims typed signature).

Claim typed data fields

ClaimTransferWithAuthorization: [
  { name: "from", type: "address" },
  { name: "to", type: "address" },
  { name: "outcome", type: "uint8" },  // YES=0, NO=1
  { name: "roundId", type: "uint64" },
  { name: "value", type: "uint256" },
  { name: "validAfter", type: "uint256" },
  { name: "validBefore", type: "uint256" },
  { name: "nonce", type: "bytes32" }
]

GET/api/trade/access-status?address=...

Request

curl "https://api.basemarket.fun/api/trade/access-status?address=0x926947ffddae36992c2365c03394c6373d4f5529"

Live Response

{
  "connected": false,
  "eligible": false,
  "message": "Connect your wallet to use this platform"
}

GET/api/trade/current-round

Request

curl https://api.basemarket.fun/api/trade/current-round

Live Response

{ "currentRound": "389" }

Click "Try it" to fetch live JSON.

Dashboard API

GET/api/dashboard/state?user=...

Returns composed dashboard data (market + trade + lp + generatedAt). Requires user context.

Sample keys from live payload

{
  "market": { "...": "..." },
  "trade": { "...": "..." },
  "lp": { "...": "..." },
  "generatedAt": "2026-02-28T17:39:14.718Z"
}

GET/api/dashboard/all-trade-history?limitRounds=2

Live summary

{
  "rounds": [389, 388],
  "events_count": 4,
  "hasMore": true,
  "nextCursorRoundId": 388
}

Click "Try it" to fetch live JSON.

Health

GET/api/health

Request

curl https://api.basemarket.fun/api/health

Live Response

{
  "status": "ok",
  "service": "basemarket-api",
  "timestamp": "2026-02-28T17:35:53.958Z"
}

Click "Try it" to fetch live JSON.