Building an automated strategy that monitors both currencies and digital assets usually runs into an immediate infrastructure hurdle: data providers segment asset classes into separate, costly subscriptions. You will have a single working Python client by the end of this guide that streams live candle updates for both BTCUSD and EURUSD through one socket connection.

TL;DR: Developers looking for cheap websocket market data often find that providers like Twelve Data and Polygon.io charge high monthly base rates or require separate add-on packages to stream forex and crypto together. The RealMarketAPI multi-asset platform provides WebSocket streaming beginning on the Plus plan at $14.99 per month for 10 concurrent connections, routing both markets over wss://api.realmarketapi.com.

The Multi-Asset Cost Floor at Polygon.io and Twelve Data

When evaluating polygon io websocket pricing, you quickly encounter asset silos. Polygon segregates stocks, options, forex, and crypto into distinct subscription lines. If your model trades BTCUSD against fiat swings or monitors EURUSD correlations alongside crypto pairs, running concurrent streaming feeds requires paying for separate plans. The baseline price escalates before you even execute your first test trade.

Twelve Data presents a similar constraint. Finding a functional twelve data websocket alternative becomes necessary once you calculate the tier upgrades needed for real-time streaming intervals across disparate exchanges. On many market data platforms, WebSocket access is locked behind enterprise tiers priced in the hundreds of dollars per month, even when an independent engineer only needs a single socket to ingest price updates.

Paying separate bills for forex and crypto feeds adds integration complexity. You end up maintaining multiple client libraries, handling mismatched heartbeat formats, and managing duplicate failover routines across independent vendor platforms.

WebSocket Allowances on RealMarketAPI Plus and Pro Plans

To budget properly, you need clear facts about how WebSocket access is provisioned. The Free plan ($0 per month, 5,000 requests) and Starter plan ($4.99 per month, 20,000 requests) are restricted to REST queries only. If you try to open a socket handshake on a Free or Starter API key, the server rejects the connection.

Streaming begins on the Plus tier:

  • Plus Plan ($14.99/mo): 75,000 REST requests, 3 months of history, and 10 concurrent WebSocket connections.
  • Pro Plan ($34.99/mo): 200,000 REST requests, 1 year of history, 100 concurrent WebSocket connections, and access to the MCP server and Intelligence endpoints.
  • Business Plan ($74.99/mo): 1,000,000 REST requests, up to 10 years of history, and 300 concurrent WebSocket connections.

Yearly billing reduces these plan costs by up to 15 percent across all paid tiers. If you run multiple daemon worker processes or distributed microservices across cloud instances, the 10-connection limit on Plus gives each service its own dedicated socket without hitting handshake rejections.

Cheap WebSocket Market Data: Connecting with an API Key

The socket authentication mechanism does not require complex challenge-response handshakes or secondary JSON login payloads. You pass the API key directly as a query parameter during the opening HTTP handshake to wss://api.realmarketapi.com.

Here is how to verify network connectivity from the command line using websocat or curl:

# Test REST connectivity first to confirm your key is valid curl "https://api.realmarketapi.com/api/v1/price?apiKey=YOUR_API_KEY&symbolCode=BTCUSD&timeFrame=M1" # Open a raw WebSocket connection with your key passed as a query param websocat "wss://api.realmarketapi.com?apiKey=YOUR_API_KEY"

The REST test confirms key validity by returning the latest candle payload with fields: SymbolCode, OpenPrice, ClosePrice, HighPrice, LowPrice, Bid, Ask, Volume, and OpenTime.

Subscribing to BTCUSD and EURUSD in a Single Session

Once the connection opens, you can listen for updates across forex and crypto pairs without opening distinct sockets for each market. Upstream liquidity flows from sources like Binance, OKX, and Coinbase for crypto, and Exness, IG Group, OANDA, and Vantage for foreign exchange.

The following Python script uses the websockets library to establish a persistent session, subscribe to both BTCUSD and EURUSD, and parse incoming bar ticks.

import asyncio import json import websockets API_KEY = "YOUR_API_KEY" WS_URL = f"wss://api.realmarketapi.com?apiKey={API_KEY}" async def market_listener(): async with websockets.connect(WS_URL) as ws: subscriptions = [ {"action": "subscribe", "symbolCode": "BTCUSD", "timeFrame": "M1"}, {"action": "subscribe", "symbolCode": "EURUSD", "timeFrame": "M1"} ] for sub in subscriptions: await ws.send(json.dumps(sub)) print(f"Subscribed to {sub['symbolCode']}") while True: raw_msg = await ws.recv() data = json.loads(raw_msg) # Field names match candle responses (values illustrative)  symbol = data.get("SymbolCode") close_price = data.get("ClosePrice") bid = data.get("Bid") ask = data.get("Ask") open_time = data.get("OpenTime") print(f"[{open_time}] {symbol} Close: {close_price} | Bid: {bid} | Ask: {ask}") if __name__ == "__main__": asyncio.run(market_listener())

If you prefer to integrate market feeds into language models instead of writing raw socket loops, you can also build an AI trading agent with a market data MCP server using the 33 pre-built tools available on the Pro tier.

Managing Connection Limits and Reconnect Logic

When writing automated trading logic, relying on raw script execution without disconnect handling causes unhandled exceptions during upstream network glitches. The standard 99.99% uptime SLA covers the infrastructure, but public internet routes between your server and the edge gateway will drop frames occasionally.

When implementing real time stock crypto websocket clients, wrap your connection call in an exponential backoff loop. Also keep your total socket count strictly below your plan threshold (10 for Plus, 100 for Pro). If your workers spin up in containers, a crash-looping service can rapidly exhaust available connection slots.

import asyncio import logging import websockets logging.basicConfig(level=logging.INFO) WS_URL = "wss://api.realmarketapi.com?apiKey=YOUR_API_KEY" async def connect_with_retry(): backoff = 1 max_backoff = 30 while True: try: logging.info("Attempting WebSocket connection...") async with websockets.connect(WS_URL) as ws: logging.info("Connected. Resetting backoff.") backoff = 1 async for message in ws: # Process message data  pass except (websockets.ConnectionClosedError, OSError) as err: logging.warning("Connection lost: %s. Retrying in %ds...", err, backoff) await asyncio.sleep(backoff) backoff = min(backoff * 2, max_backoff) if __name__ == "__main__": asyncio.run(connect_with_retry())

For systems that execute risk-managed orders based on technical triggers, you can pair this streaming loop with automated risk guards. Review how to build a trading bot MCP server setup with Python risk loops for patterns on handling position safeguards.

Check the plan details at https://realmarketapi.com/?utm_source=devto&utm_medium=blog&utm_campaign=real-time-websocket-cost-comparison, obtain an API key on the Plus tier, and run the Python listener script against BTCUSD and EURUSD to verify streaming data in your development environment.