# Scalpel vs TWS: what changes when you add Scalpel to TWS > Scalpel vs TWS: Scalpel runs on top of TWS, so you keep your IBKR account, routing and data. What changes, what TWS still does better, who should stay. Source: https://scalpeltrade.com/compare/tws By Scalpel Team. Published 2026-09-13, last changed 2026-10-15. 8 min read. **In short:** Scalpel is not a replacement for TWS: it runs on top of TWS or IB Gateway, through the API, on the same computer. You keep your Interactive Brokers account, SMART routing, fills, market data and commissions. What changes is the screen you trade from: one keyboard-first desk per stock, buys sized by risk, stops you drag on the chart that can exit in the pre-market, a momentum scanner with borrow and dilution reads, a SIM mode on the live book, and voice callouts. Everything outside long US stocks (shorting, options, futures, forex, bracket orders at the broker, mobile) stays in TWS. Traders searching for a TWS alternative for day trading usually like Interactive Brokers and dislike Trader Workstation: the window juggling, the hotkey setup, sizing in shares by hand, stops that do nothing before 09:30 ET. This page compares TWS alone with TWS plus Scalpel, says plainly what Scalpel does not do, and lists who should stay on TWS alone. Scalpel is independent and not affiliated with or endorsed by Interactive Brokers. ## Scalpel vs TWS: it is TWS plus Scalpel Scalpel has no route into your account of its own. Interactive Brokers only lets outside programs in through the API that TWS and IB Gateway serve, so one of the two must be running and logged in on the same machine, with the API switched on. IB Gateway is TWS without the trading screens: it uses far less memory and serves the same API ([IB Gateway vs TWS for day trading](https://scalpeltrade.com/blog/ib-gateway-vs-tws)). IBKR allows one trading-platform session per username, so there are three ways to run: | Setup | What runs | Cost | | --- | --- | --- | | Scalpel instead of the TWS screens | IB Gateway plus Scalpel | Nothing extra; the lightest setup | | Scalpel alongside TWS | TWS with the API on, plus Scalpel | Nothing extra; you keep every TWS window | | Both fully open at once | TWS on one username, IB Gateway for Scalpel on a second | Market data is billed per username, so the second login needs its own subscriptions | ![A stack diagram: Scalpel on top adds the desks, risk sizing, pre-market stops, scanner, SIM and voice; it talks to TWS or IB Gateway over the API on the same computer; Interactive Brokers below keeps the account, routing, fills, commissions, market data and positions](https://scalpeltrade.com/images/compare/tws/stack.webp) *Scalpel and TWS or IB Gateway run on the same computer, linked by the API. Your account, routing, fills, commissions, data and positions stay with IBKR, and everything outside long US stocks stays in TWS.* ## What you keep - **Your account and your money.** Scalpel never holds funds. LIVE orders go to your IBKR account and show in TWS like any other order. - **Routing and fills.** Every order goes to IBKR with SMART routing, which looks for the best price across venues. There is no route setting in Scalpel. - **Commissions.** IBKR charges its usual rates. In LIVE, Scalpel books the commission IBKR reports for each fill in its FEE column, so your P&L is net of real fees. - **Market data.** Scalpel uses the subscriptions already on your IBKR username: live US stock data for quotes, the tape and charts, and a depth feed such as NASDAQ TotalView-OpenView for Level 2. No extra feed, no charting subscription ([which data you need](https://scalpeltrade.com/guides/ibkr-market-data-for-day-trading)). - **Your positions.** LIVE positions reconcile from IBKR when Scalpel connects. A position closed in TWS closes in Scalpel too, and the header can show either the whole account or only Scalpel's trades. ## What changes ### One keyboard-first desk per stock TWS gives you separate windows (Level 2, time and sales, chart, order entry) that you link by color group and arrange yourself ([a TWS day trading layout](https://scalpeltrade.com/blog/tws-day-trading-layout) shows how). Scalpel gives you up to six desks side by side, each a complete station for one symbol: a DAS-style Level 2 montage with the tape beside it, a candlestick chart, an order bar, and orders and positions. One desk is focused at a time and takes your keys. *Screenshot: The cockpit in SIM: the header, four trader desks each with Level 2, the tape, a chart, an order bar and orders and positions, the + rail for more desks, and the status bar. Demo data.* The hotkeys work out of the box: `Shift+1` to `Shift+4` buy with your four presets, `Ctrl+Z` sells the whole position at the bid, `Ctrl+X` sells half, `B` moves the stop to breakeven, and `Esc` flattens everything. Every key is rebindable, and trading keys never fire while you type in a field. ### Sizing by risk TWS hotkeys send a share size from the order preset. Scalpel's buy presets can be shares, dollars or risk. With a risk preset, the share count is worked out when you press, from the live price and the stop distance: a $500 Risk (Cents) preset with a 30 cent stop buys 1,666 shares of ABCD, so a stop-out costs about $500 plus slippage and fees ([sizing presets](https://scalpeltrade.com/guides/sizing-presets)). ### Stops that work in the pre-market Before 09:30 ET and after 16:00 ET, US exchanges take [limit orders](https://scalpeltrade.com/guides/glossary#limit-order) only. A plain stop at IBKR becomes a market order when it triggers, so it cannot protect a pre-market trade, and a stop-limit can be jumped when price gaps through its limit. Scalpel arms a working stop, a wider catastrophe net and a take-profit on every entry, drawn on the chart, where you drag them. They are watched by the app, not resting at IBKR. When price trades through the stop, Scalpel sends a sell limit 5 cents under the last trade, flagged for extended hours, and re-prices it if the market runs away ([how stops work](https://scalpeltrade.com/guides/how-stops-work)). *Screenshot: 400 ABCD at 5.50: the stop at 5.38 reads -48.00 (-1.0R), the target at 5.74 reads +96.00 (+2.0R), and the entry line +80.00 (+1.7R) at a 5.70 last. Demo data.* **This can cost you money.** App-monitored stops only work while Scalpel is running with a live feed. If your computer sleeps, crashes or loses its connection, nothing protects the position. No fill is guaranteed: in a fast drop price can run past any limit. ### Scanner and intel TWS has a powerful Advanced Market Scanner you set up yourself. Scalpel runs five of IBKR's own scans over the API (top gainers, volume spikes, halts, hot by volume, gappers; pre-market included), merges them into one list ranked live, and adds high-of-day, running-up and setup scans on top. Next to each name it shows borrow, dilution and catalyst reads from free sources: IBKR's borrow file and news, SEC EDGAR filings, FINRA short interest and Nasdaq's Reg SHO list. ### Practice, guards and sound - **SIM against the live book.** IBKR's paper account is a separate login with simulated fills. Scalpel's SIM fills against the live book you are watching, with IBKR-style commissions, and switches to LIVE without a restart. - **Risk guards.** A daily loss limit that blocks new entries, a fat-finger cap and a position cap in front of every order. - **Voice and tape sound.** Spoken callouts for fills, exits and stops, and an optional tape sound that plays the prints so you can hear the flow while you watch the book. ## TWS alone vs TWS plus Scalpel | | TWS alone | TWS plus Scalpel | | --- | --- | --- | | Cost | Free with the account | $299 once, lifetime license | | Account, routing, commissions | IBKR, SMART or a chosen exchange | IBKR, SMART only | | Market data | Your IBKR subscriptions | The same subscriptions, nothing extra | | Layout | Linked windows you arrange | Up to six desks, one symbol each | | Hotkeys | Tied to order presets you configure | Defaults that work out of the box, rebindable | | Size per press | Shares from the preset | Shares, dollars or risk at the instant you press | | Stops | Orders resting at IBKR | App-monitored, dragged on the chart | | Stops with the computer off | Yes, held by IBKR | No: Scalpel must be running | | Pre-market stop exit | Stop-limit that can be jumped | Limit 5 cents under the last trade, re-priced | | Practice | IBKR paper account | SIM on the live book, no restart | | Audio | Alert sounds | Voice callouts and tape sound | | Shorting | Yes | No: long only | | Options, futures, forex, bonds | Yes | No: US stocks only | | Platforms | Windows, Mac, Linux, mobile | Windows 10 and 11, and Macs with Apple silicon | ## What TWS does that Scalpel does not Scalpel is specialized on purpose. Everything below stays in TWS: - **Shorting.** Scalpel is long only: every sell is capped to the shares you hold ([long only](https://scalpeltrade.com/guides/long-only)). - **Options, futures, forex, bonds and crypto.** Scalpel trades US stocks only, and none of these are planned. - **Orders held at the broker.** Brackets, OCA groups, conditional orders and IBKR's algos rest on IBKR's side and keep working with your computer off. - **Route choice.** TWS lets you pick an exchange as the destination; Scalpel always uses SMART. - **Portfolio and account tools.** Risk analysis, reports, funding and everything else in TWS and Client Portal. - **Mobile and other platforms.** IBKR's mobile app, and TWS on Linux and Intel Macs. Scalpel runs on Windows and on Macs with Apple silicon only. - **Automation.** Scalpel has no auto trader and never trades for you. ## Requirements **Before you start:** - An Interactive Brokers account with live US stock data, plus a depth subscription for Level 2. - TWS or IB Gateway running and logged in on the same computer as Scalpel. - The API switched on: in TWS, **Configure > API > Settings > Enable ActiveX and Socket Clients**; in IB Gateway, **Configure > Settings > API**. - The socket port in TWS or IB Gateway matching **Settings > Connection > Port** in Scalpel (7497 for TWS by default, 4001 for IB Gateway). - Windows 10 or 11. Both TWS and IB Gateway force a daily re-login unless you set auto-restart, and both ask for two-factor approval at login. The step-by-step is in [connect Interactive Brokers](https://scalpeltrade.com/guides/connect-interactive-brokers), and the wider account setup in [day trading on Interactive Brokers](https://scalpeltrade.com/blog/day-trading-interactive-brokers). ## Who should stay on TWS alone - **Short sellers**, and anyone whose playbook includes shorts. - **Options, futures and forex traders.** - **Swing traders and investors** who want stops resting at the broker while the computer is off. - **Traders who need Linux, an Intel Mac or mobile** as their main screen today. - **Traders who want direct routing** to a chosen exchange. - **Anyone who is happy with their TWS setup.** If your hotkeys, layout and stops already work for you, there is nothing to fix. TWS plus Scalpel is for one kind of trader: long-only, scalping US stocks, often small caps in the pre-market, who wants a keyboard-first desk, sizing by risk and pre-market stop exits on the IBKR account they already have. It is $299 once with a 7-day refund ([pricing](https://scalpeltrade.com/pricing)). Start in SIM and stay there until your results are consistent: this style of trading is hard, and most people who try it lose money. *Trading carries a significant risk of loss. Nothing here is financial advice.* ## Questions **Does Scalpel replace TWS?** No. Scalpel connects to your Interactive Brokers account through the API that TWS or IB Gateway serves, so one of them must be running and logged in on the same computer. With IB Gateway you can skip the TWS screens entirely. **What is a good TWS alternative for day trading?** It depends on what you trade. For long-only scalping of US stocks, a front end such as Scalpel runs on top of your IBKR account. For shorting, options or direct routing, TWS itself or a platform such as DAS Trader Pro fits better. **Do I need to pay for market data again to use Scalpel?** No. Scalpel uses the IBKR market data subscriptions already on your username. If you run TWS and IB Gateway at once on two usernames, the second username needs its own subscriptions. **Can I still use TWS while Scalpel is running?** Yes. Run TWS with the API on and Scalpel connects to it, so you keep every TWS window. Trades you place in TWS show up in your account as usual. **Are Scalpel's stops held at Interactive Brokers?** No. They are watched by Scalpel and fire a real exit order when price trades through, so they only work while Scalpel is running with a live feed. In return they can exit in the pre-market, where a plain stop at the broker cannot. **Can I short or trade options through Scalpel?** No. Scalpel is long only and trades US stocks only. Use TWS for shorts, options, futures and forex.