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Samuel EF. Tinnerholm
Samuel EF. Tinnerholm

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DomeAPI Alternative: How to Migrate Your Bots to pmxt

#opensource #tutorial #web3 #typescript

Migrating from DomeAPI to pmxt

This guide helps you migrate your Polymarket integration from DomeAPI to pmxt.

Why migrate?

DomeAPI is shutting down March 31, 2025. Polymarket acquired DomeAPI and is discontinuing the service. If you rely on DomeAPI for market data or trading, you need to migrate before that date.

DomeAPI pmxt
Authentication API key (paid tiers) No API key for market data
Exchanges Polymarket, Kalshi Polymarket, Kalshi, Limitless, Probable, Baozi, Myriad
Trading Order router (linked wallet) Native (your private key, direct on-chain)
License Proprietary service Open source (MIT)
Rate limits Tiered (10-300 QPS) Exchange-native

Installation

Before (DomeAPI):

# TypeScript
npm install @dome-api/sdk

# Python
pip install dome-api-sdk
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After (pmxt):

# TypeScript
npm install pmxtjs

# Python
pip install pmxt
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Client initialization

Before (DomeAPI):

// TypeScript
import { DomeClient } from '@dome-api/sdk';
const dome = new DomeClient({ apiKey: 'your-api-key-here' });
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# Python
from dome_api_sdk import DomeClient
dome = DomeClient({"api_key": "your-api-key-here"})
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After (pmxt):

// TypeScript
import pmxt from 'pmxtjs';
const poly = new pmxt.Polymarket();
const kalshi = new pmxt.Kalshi();
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# Python
import pmxt
poly = pmxt.Polymarket()
kalshi = pmxt.Kalshi()
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No API key required for market data. The pmxt server starts automatically on first use.

Method mapping

Market price

Before (DomeAPI):

const price = await dome.polymarket.markets.getMarketPrice({ token_id: '...' });
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price = dome.polymarket.markets.get_market_price({"token_id": "..."})
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After (pmxt):

const markets = await poly.fetchMarkets({ query: 'Trump' });
const price = markets[0].yes?.price; // 0.0 to 1.0
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markets = poly.fetch_markets(query='Trump')
price = markets[0].yes.price  # 0.0 to 1.0
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Note: DomeAPI returns price as a raw value. pmxt prices are always 0.0-1.0 (probability). Multiply by 100 for percentage.

Markets search

Before (DomeAPI REST):

GET https://api.domeapi.io/v1/polymarket/markets
  ?search=Trump
  &status=open
  &min_volume=10000
  &limit=20
  &pagination_key=<cursor>
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After (pmxt):

const markets = await poly.fetchMarkets({
  query: 'Trump',
  status: 'active',
  limit: 20,
  offset: 0,   // offset-based, not cursor-based
});
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markets = poly.fetch_markets(
    query='Trump',
    status='active',
    limit=20,
    offset=0,
)
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Pagination change: DomeAPI uses cursor-based pagination (pagination_key). pmxt uses offset-based pagination (offset).

Filter by slug/condition_id:

// DomeAPI: filter by market_slug or condition_id query params
// pmxt: use the slug param
const markets = await poly.fetchMarkets({ slug: 'will-trump-win-the-2024-election' });
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Events

Before (DomeAPI):

GET https://api.domeapi.io/v1/polymarket/events
  ?search=Fed+Chair
  &status=open
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After (pmxt):

const events = await poly.fetchEvents({ query: 'Fed Chair' });
const market = events[0].markets.match('Kevin Warsh');
console.log(market.yes?.price);
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events = poly.fetch_events(query='Fed Chair')
market = events[0].markets.match('Kevin Warsh')
print(market.yes.price)
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Candlesticks (OHLCV)

Before (DomeAPI):

GET https://api.domeapi.io/v1/polymarket/candlestick
  ?condition_id=<condition_id>
  &interval=1h
  &start_ts=<unix_seconds>
  &end_ts=<unix_seconds>
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After (pmxt):

The key difference: pmxt takes an outcome_id, not a condition_id. Use outcome.outcomeId (TypeScript) or outcome.outcome_id (Python).

const markets = await poly.fetchMarkets({ query: 'Trump' });
const outcomeId = markets[0].outcomes[0].outcomeId; // NOT market.marketId

const candles = await poly.fetchOHLCV(outcomeId, {
  resolution: '1h',                  // '1m' | '5m' | '15m' | '1h' | '6h' | '1d'
  start: new Date('2025-01-01'),     // Date object (not unix seconds)
  end: new Date('2025-02-01'),
  limit: 100,
});

// candle.timestamp is Unix milliseconds (DomeAPI may differ)
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markets = poly.fetch_markets(query='Trump')
outcome_id = markets[0].outcomes[0].outcome_id  # NOT market.market_id

candles = poly.fetch_ohlcv(
    outcome_id,
    resolution='1h',
    start='2025-01-01',
    end='2025-02-01',
    limit=100,
)
# candle.timestamp is Unix milliseconds
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Interval name changes:

DomeAPI pmxt
1m 1m
5m 5m
15m 15m
1h 1h
6h 6h
1d 1d

Order book

Before (DomeAPI):

GET https://api.domeapi.io/v1/polymarket/orderbook-history
  ?token_id=<token_id>
  &start_ts=...
  &end_ts=...
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DomeAPI provides historical orderbook snapshots. pmxt provides the current live order book.

After (pmxt):

const markets = await poly.fetchMarkets({ query: 'Trump' });
const outcomeId = markets[0].outcomes[0].outcomeId;

const book = await poly.fetchOrderBook(outcomeId);
console.log('Best bid:', book.bids[0].price);
console.log('Best ask:', book.asks[0].price);
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markets = poly.fetch_markets(query='Trump')
outcome_id = markets[0].outcomes[0].outcome_id

book = poly.fetch_order_book(outcome_id)
print('Best bid:', book.bids[0].price)
print('Best ask:', book.asks[0].price)
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Calculate execution price (new in pmxt, not in DomeAPI):

const price = poly.getExecutionPrice(book, 'buy', 100); // avg price for 100 shares
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price = poly.get_execution_price(book, 'buy', 100)
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Trade history

Before (DomeAPI):

GET https://api.domeapi.io/v1/polymarket/trade-history
  ?token_id=<token_id>
  &start_ts=<unix_seconds>
  &end_ts=<unix_seconds>
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After (pmxt):

const trades = await poly.fetchTrades(outcomeId, {
  start: new Date('2025-01-01'),
  end: new Date('2025-02-01'),
  limit: 100,
});
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trades = poly.fetch_trades(
    outcome_id,
    start='2025-01-01',
    end='2025-02-01',
    limit=100,
)
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Time format change: DomeAPI uses Unix seconds. pmxt uses Date objects (TypeScript) or ISO strings (Python). Returned timestamps are Unix milliseconds in both.

Positions

Before (DomeAPI):

GET https://api.domeapi.io/v1/polymarket/positions
  ?wallet=<address>
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DomeAPI fetches positions for any wallet address publicly.

After (pmxt):

// Requires authentication - fetches YOUR positions
const positions = await poly.fetchPositions();
positions.forEach(pos => {
  console.log(`${pos.outcomeLabel}: ${pos.size} @ $${pos.entryPrice}`);
  console.log(`Unrealized P&L: $${pos.unrealizedPnL}`);
});
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positions = poly.fetch_positions()
for pos in positions:
    print(f"{pos.outcome_label}: {pos.size} @ ${pos.entry_price}")
    print(f"Unrealized P&L: ${pos.unrealized_pnl:.2f}")
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pmxt does not support looking up arbitrary wallet positions by address. It only returns your own positions via authenticated requests.

Wallet P&L

DomeAPI provides wallet/pnl for realized P&L by wallet address. pmxt does not have a direct equivalent - use fetchPositions() which includes unrealized_pnl and realized_pnl fields for your own account.

Real-time data (WebSocket)

Before (DomeAPI):

// DomeAPI WebSocket for Polymarket order data
const ws = dome.polymarket.websocket.subscribe({ token_id: '...' });
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After (pmxt):

const outcomeId = markets[0].outcomes[0].outcomeId;

// Stream order book updates
for await (const book of poly.watchOrderBook(outcomeId)) {
  console.log('Best bid:', book.bids[0].price);
}

// Stream trades
for await (const trade of poly.watchTrades(outcomeId)) {
  console.log('Trade:', trade.price, trade.amount);
}
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# Python (async generator)
async for book in poly.watch_order_book(outcome_id):
    print('Best bid:', book.bids[0].price)
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Trading (new in pmxt)

DomeAPI has an "Order Router" that requires linking your wallet. pmxt trades directly using your private key.

Setup (Polymarket) 

const exchange = new pmxt.Polymarket({
  privateKey: process.env.POLYMARKET_PRIVATE_KEY,
  funderAddress: process.env.POLYMARKET_PROXY_ADDRESS, // optional
});
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import os
exchange = pmxt.Polymarket(
    private_key=os.getenv('POLYMARKET_PRIVATE_KEY'),
    proxy_address=os.getenv('POLYMARKET_PROXY_ADDRESS'),  # optional
)
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Place an order 

const markets = await exchange.fetchMarkets({ query: 'Trump' });
const order = await exchange.createOrder({
  marketId: markets[0].marketId,
  outcomeId: markets[0].yes?.outcomeId,
  side: 'buy',
  type: 'limit',
  amount: 10,   // contracts
  price: 0.55,  // 0.0-1.0
});
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markets = exchange.fetch_markets(query='Trump')
order = exchange.create_order(
    outcome=markets[0].yes,  # shorthand
    side='buy',
    type='limit',
    amount=10,
    price=0.55,
)
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Data model changes

Market ID and Outcome ID

DomeAPI pmxt
condition_id market.marketId / market.market_id
token_id outcome.outcomeId / outcome.outcome_id
market_slug market.url (full URL)

Outcome structure

Before (DomeAPI):

{
  "side_a": { "id": "...", "label": "Yes" },
  "side_b": { "id": "...", "label": "No" }
}
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After (pmxt):

market.outcomes        // all outcomes as array
market.yes             // shorthand for binary Yes outcome
market.no              // shorthand for binary No outcome
market.outcomes[0].outcomeId
market.outcomes[0].label
market.outcomes[0].price  // 0.0 to 1.0
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Price scale

DomeAPI pmxt
Varies (check docs) Always 0.0 to 1.0 (multiply by 100 for %)

Timestamp format

DomeAPI pmxt
Unix seconds (some endpoints) Unix milliseconds (all endpoints) 
# Convert pmxt timestamp to datetime
from datetime import datetime
dt = datetime.fromtimestamp(candle.timestamp / 1000)
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Pagination

DomeAPI pmxt
Cursor-based (pagination_key) Offset-based (limit + offset)

Feature gaps

Some DomeAPI features have no direct pmxt equivalent:

DomeAPI feature pmxt alternative
Wallet positions by address fetch_positions() (own account only)
Wallet P&L by address fetch_positions() unrealized/realized P&L
Sports cross-platform matching Not available
Binance / Chainlink price feeds Not available
Activity feed by wallet Not available
Historical orderbook snapshots watch_order_book() for live data

Multi-exchange support (new in pmxt)

pmxt gives you the same API across all supported exchanges:

const poly = new pmxt.Polymarket();
const kalshi = new pmxt.Kalshi();
const limitless = new pmxt.Limitless();

// Same methods on all exchanges
const polyMarkets = await poly.fetchMarkets({ query: 'Fed Chair' });
const kalshiMarkets = await kalshi.fetchMarkets({ query: 'Fed Chair' });
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Quick reference

Task DomeAPI pmxt (TypeScript) pmxt (Python)
Get market price getMarketPrice({ token_id }) fetchMarkets({ query }) then .yes.price fetch_markets(query=...) then .yes.price
Search markets GET /polymarket/markets?search= fetchMarkets({ query }) fetch_markets(query=...)
Get OHLCV GET /polymarket/candlestick?condition_id= fetchOHLCV(outcomeId, { resolution }) fetch_ohlcv(outcome_id, resolution=...)
Get order book GET /polymarket/orderbook-history?token_id= fetchOrderBook(outcomeId) fetch_order_book(outcome_id)
Get trades GET /polymarket/trade-history?token_id= fetchTrades(outcomeId, params) fetch_trades(outcome_id, ...)
Real-time book WebSocket subscribe watchOrderBook(outcomeId) watch_order_book(outcome_id)
Place order Order Router API createOrder(params) create_order(...)
Get positions GET /polymarket/positions?wallet= fetchPositions() fetch_positions()
Get balance N/A fetchBalance() fetch_balance()

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