Interactive Brokers API in Python: paper to first call

Steps

1. Log in to paper, not live

   Start TWS or IB Gateway and log in with your paper trading username. It is separate from your live one and sits in Client Portal settings. IBKR's older setup guide gives the default TWS socket ports as 7497 for a paper session and 7496 for a live one, and says they can be changed. This site also holds 4002 paper and 4001 live for IB Gateway: those two were not found on the IBKR pages read on 12 October 2026, so check the socket port shown in your own API settings. Get the port wrong and you are either not connected or connected to real money.

   interactivebrokers.github.iochecked 25 Sep 2026

2. Switch the API on

   In TWS open Global Configuration, then API, then Settings. Tick Enable ActiveX and Socket Clients and check the socket port. Read-Only API hides order information from the API. Leave it on for this quickstart and connect with readonly=True; IBKR's guide says to disable it for API use, so untick it when you are ready to send orders.

   interactivebrokers.comchecked 25 Sep 2026

3. Install ib_async

   ib_async is the community successor to ib_insync and needs Python 3.10 or later. IBKR's own ibapi client needs 3.11. For the JavaScript and curl tabs, run the Java based Client Portal Gateway instead and log in at https://localhost:5000.

   Python

   # Python 3.10 or later
   pip install ib_async
   

   JavaScript

   // Nothing to install: Node 18 or later has fetch built in.
   // Start the Client Portal Gateway (needs a Java runtime), then log in at https://localhost:5000
   //   macOS or Linux: bin/run.sh root/conf.yaml
   //   Windows:        bin\run.bat root\conf.yaml
   

   curl

   # Client Portal Gateway (needs a Java runtime), from its folder:
   bin/run.sh root/conf.yaml
   # Windows: bin\run.bat root\conf.yaml
   # Then open https://localhost:5000 in a browser and log in with your paper username.
   

   pypi.orgchecked 25 Sep 2026

4. Connect and check the clock

   Connect to 127.0.0.1 on the paper port with a clientId unique to this script. reqCurrentTime proves the socket works. On the Web API, POST /iserver/auth/status should come back with authenticated true. It is a POST, not a GET.

   Python

   from ib_async import IB
   
   ib = IB()
   # TWS paper 7497, IB Gateway paper 4002
   ib.connect('127.0.0.1', 7497, clientId=1, readonly=True)
   print("Server time:", ib.reqCurrentTime())
   print("Accounts:", ib.managedAccounts())
   ib.disconnect()
   

   JavaScript

   // This tab uses the Client Portal Web API with fetch, not the TWS socket API.
   // The gateway runs on your own machine with a self-signed certificate.
   // For localhost only, run with: NODE_TLS_REJECT_UNAUTHORIZED=0 node step.mjs
   const BASE_URL = "https://localhost:5000/v1/api";
   
   const res = await fetch(`${BASE_URL}/iserver/auth/status`, { method: "POST" });
   if (!res.ok) throw new Error(`HTTP ${res.status}`);
   const status = await res.json();
   console.log("authenticated:", status.authenticated, "connected:", status.connected);
   

   curl

   # -k accepts the gateway's self-signed certificate. Use it against localhost only.
   curl -k -s -X POST "https://localhost:5000/v1/api/iserver/auth/status"
   

   ibkrcampus.comchecked 25 Sep 2026

5. First real call: your account

   accountSummary returns balances as AccountValue rows. If you see NetLiquidation, you are in. On the Web API, call GET /portfolio/accounts first: IBKR requires it before any other /portfolio endpoint.

   Python

   from ib_async import IB
   
   ib = IB()
   ib.connect('127.0.0.1', 7497, clientId=1, readonly=True)
   for v in ib.accountSummary():
       if v.tag in ('NetLiquidation', 'AvailableFunds'):
           print(v.account, v.tag, v.value, v.currency)
   ib.disconnect()
   

   JavaScript

   // This tab uses the Client Portal Web API with fetch, not the TWS socket API.
   // The gateway runs on your own machine with a self-signed certificate.
   // For localhost only, run with: NODE_TLS_REJECT_UNAUTHORIZED=0 node step.mjs
   const BASE_URL = "https://localhost:5000/v1/api";
   
   const res = await fetch(`${BASE_URL}/portfolio/accounts`);
   if (!res.ok) throw new Error(`HTTP ${res.status}`);
   const accounts = await res.json();
   console.log(accounts.map(a => a.id));
   

   curl

   # Set IBKR_ACCOUNT_ID as an environment variable first (an id from the call above).
   # Must be called before other /portfolio endpoints
   curl -k -s "https://localhost:5000/v1/api/portfolio/accounts"
   
   # Then, for example:
   curl -k -s "https://localhost:5000/v1/api/portfolio/$IBKR_ACCOUNT_ID/summary"
   

   interactivebrokers.comchecked 25 Sep 2026

6. Prices without paying for data

   Call reqMarketDataType(3) to accept delayed data when you have no live subscription. Forex needs no extra market data subscription, so EURUSD midpoint bars are the safest first request. Live data needs 500 USD in the account, the subscription cost on top and the Market Data API Acknowledgement.

   Python

   from ib_async import IB, Forex
   
   ib = IB()
   ib.connect('127.0.0.1', 7497, clientId=1, readonly=True)
   ib.reqMarketDataType(3)  # 1 live, 2 frozen, 3 delayed, 4 delayed frozen
   
   contract = Forex('EURUSD')
   ib.qualifyContracts(contract)  # fills in conId and exchange; skip it and the request can come back empty
   
   bars = ib.reqHistoricalData(
       contract,
       endDateTime='',
       durationStr='1 D',
       barSizeSetting='1 hour',
       whatToShow='MIDPOINT',
       useRTH=False,  # forex has no regular trading hours, so useRTH=True often returns an empty list
   )
   if not bars:
       raise SystemExit('No bars returned. Check the symbol, the duration and that the gateway is connected.')
   for b in bars[-3:]:
       print(b.date, b.open, b.high, b.low, b.close)
   ib.disconnect()
   

   JavaScript

   // This tab uses the Client Portal Web API with fetch, not the TWS socket API.
   // The gateway runs on your own machine with a self-signed certificate.
   // For localhost only, run with: NODE_TLS_REJECT_UNAUTHORIZED=0 node step.mjs
   // Snapshot pre-flight and field 31 are not confirmed on a page we opened.
   // The first call starts the stream; repeat it to get values.
   const BASE_URL = "https://localhost:5000/v1/api";
   const CONID = process.env.IBKR_CONID; // the contract id, set as an environment variable
   const url = `${BASE_URL}/iserver/marketdata/snapshot?conids=${CONID}&fields=31`;
   
   await fetch(url); // pre-flight
   await new Promise(r => setTimeout(r, 1000));
   const res = await fetch(url);
   console.log(await res.json());
   

   curl

   # Snapshot pre-flight and field 31 (last price) are not confirmed on a page we opened.
   # Set IBKR_CONID (the contract id) as an environment variable, call once, wait, call again.
   curl -k -s "https://localhost:5000/v1/api/iserver/marketdata/snapshot?conids=$IBKR_CONID&fields=31"
   sleep 1
   curl -k -s "https://localhost:5000/v1/api/iserver/marketdata/snapshot?conids=$IBKR_CONID&fields=31"
   

   interactivebrokers.comchecked 25 Sep 2026

Interactive Brokers limits to pace against

Sources

• IBKR TWS API documentation, TWS configuration for API usechecked 12 Oct 2026
• IBKR Campus: market data subscriptionschecked 25 Sep 2026
• IBKR Web API documentation, using a paper accountchecked 12 Oct 2026
• IBKR Campus: Web API documentationchecked 12 Oct 2026
• IBKR Campus: launching and authenticating the gatewaychecked 25 Sep 2026
• ib_async documentationchecked 25 Sep 2026
• PyPI: ib_asyncchecked 25 Sep 2026
• ib_async source: ib.pychecked 25 Sep 2026
• TWS API guide: initial setup (legacy docs)checked 12 Oct 2026