Best paper trading apps for algo/API testing (2026)
We track 5 simulators for algo/API testing. They are ordered by how completely their details are verified from provider pages, not by quality or payment.
Of these, 4 are listed as free (Interactive Brokers Paper Trading, TradeStation Simulator, Alpaca Paper Trading API, Binance Futures Testnet), 3 use real-time or live data at least partly (Interactive Brokers Paper Trading, TradeStation Simulator, Alpaca Paper Trading API), and 1 can be used without a brokerage account (Alpaca Paper Trading API).
The most completely documented options here are Interactive Brokers Paper Trading (price: Free; data: Free trial: delayed 10-15 min (OTC spot FX & metals non-delayed); paper account mirrors live data subscriptions; starting balance: US$1,000,000 (paper account)); TradeStation Simulator (price: Free with account; data: Free real-time data for non-professionals (funded account required); starting balance: Unlimited paper dollars); Alpaca Paper Trading API (price: Free; data: Real-time IEX data (Paper Only accounts get IEX only); starting balance: $100,000 default; balance set when creating a new paper account).
How to choose: decide first whether you need the same market you will trade for real (e.g. NSE F&O vs US stocks), whether delayed quotes are acceptable for your style (they are fine for long-term practice, poor for day trading), and whether the app forces you to open a brokerage account. Each linked listing shows its sources so you can confirm the details.
| Simulator | Assets | Data | Price | Account |
|---|---|---|---|---|
| Interactive Brokers Paper Trading | stocks, ETFs, options, futures, forex, crypto, bonds, metals | Free trial: delayed 10-15 min (OTC spot FX & metals non-delayed); paper account mirrors live data subscriptions | Free | Free trial, or paper account once a live account is approved (funding not required for approval) |
| TradeStation Simulator | stocks, ETFs, mutual funds, options, futures | Free real-time data for non-professionals (funded account required) | Free with account | Funded TradeStation account required |
| Alpaca Paper Trading API | stocks | Real-time IEX data (Paper Only accounts get IEX only) | Free | Paper Only Account needs only an email |
| Binance Futures Testnet | crypto futures | unknown | Free | Binance account (Futures mock trading) |
| TradersPost (paper broker) | stocks, options, futures, crypto | unknown | 7-day free trial; Starter $41.65/mo billed yearly; extra paper accounts $5/mo | unknown |
FAQ
What is the best paper trading app for algo/API testing?
It depends on your market and data needs. The most completely documented options in our dataset are Interactive Brokers Paper Trading, TradeStation Simulator, Alpaca Paper Trading API. Compare data delay, price and account rules in the table above.
Which paper trading apps for algo/API testing are free?
Listed as free: Interactive Brokers Paper Trading, TradeStation Simulator, Alpaca Paper Trading API, Binance Futures Testnet. Some 'free' simulators require a funded or approved brokerage account; see each listing.
Which have real-time data?
Real-time or live data (at least partly): Interactive Brokers Paper Trading, TradeStation Simulator, Alpaca Paper Trading API. Check each listing for delays on specific markets.
Can I paper trade without opening a brokerage account?
Yes, these need no brokerage account: Alpaca Paper Trading API.
Comparisons on this list
Related lists
Information only, not financial advice. Simulated results do not predict real results. Features and availability change and vary by country; check the provider's site. Sponsored or affiliate links, if any, are labelled.