Key takeaways
- Market Replay is a Desktop feature. It runs through NinjaTrader Desktop's Playback connection, which means Windows.
- Most failures are data, not bugs. Missing replay data, an open live connection, the wrong contract month or corrupted files explain most "not working" reports.
- A browser tool trades depth for convenience. No downloads and it works on a Mac, but you get index CFD prices instead of CME futures with depth of market.
Short answer: if you trade order flow on CME futures, stay with NinjaTrader Market Replay and fix the setup. If you want to practise price action on index charts without Windows, downloads or contract months, a browser replay tool gets you there in minutes. Both are legitimate ways to rehearse a strategy on past sessions; they suit different traders.
The NinjaTrader details below come from its own help guide and staff answers on its support forum, read on 18 October 2026.
How NinjaTrader Market Replay works
Market Replay plays back recorded market data so you can trade a past session on a simulation account. NinjaTrader's help guide describes two kinds of data the Playback connection can run on:
- Market Replay data — the most accurate option, holding both level I and level II (market depth) data.
- Historical tick data — the fallback when replay data is missing; less accurate, because there is no level II.
Getting there takes four steps:
- Connect to your live data feed. NinjaTrader staff note that you need that connection to download replay data.
- Download the data. Open Tools > Historical Data, expand "Get Market Replay data", choose the instrument and dates, and wait for the download to finish. You can also record live sessions yourself with the market recorder.
- Disconnect, then connect to Playback. The Playback connection requires every other connection to be closed. Choose it from the Connections menu in the Control Center.
- Replay. The Playback control window shows the date and time of the play head; play, pause and change speed as you trade.
Market Replay not working? Check these first
| Symptom | Likely cause | Fix |
|---|---|---|
| Playback will not connect | Another connection is still open | Disconnect every live and sim connection, then connect to Playback |
| Chart is empty in Playback | No replay data for that instrument and date | Download it in Historical Data, or switch Playback to Historical to use tick data |
| Download never starts | Connected to Playback, or no live data connection | Leave Playback, connect your data feed, download again |
| Data exists but nothing plays | Wrong contract month on the chart | Open the contract month that was front month on that date |
| Replay stutters or stops | Corrupted or partial files | Delete the replay and historical files for those dates and re-download |
If the list does not solve it, NinjaTrader's support forum has long threads on Playback problems; search it for the exact message you see. And if you are on a Mac, Market Replay first needs NinjaTrader Desktop running in Windows — see how to run NinjaTrader on a Mac.
Market Replay vs NinjaTrader backtesting
The two get mixed up. Market Replay is manual: you sit through a past session and make every decision yourself, which is what builds execution skill. Backtesting in NinjaTrader usually means the Strategy Analyzer, which runs a coded NinjaScript strategy over historical data in seconds and reports the results. You need the code before the Strategy Analyzer is useful; you only need a plan before Market Replay is.
Most discretionary traders want the first and end up being sold the second. A sensible order is to replay a setup by hand until you can describe its rules exactly, then automate it.
NinjaTrader Market Replay vs a browser replay tool
| NinjaTrader Market Replay | FxBacktest | |
|---|---|---|
| Runs on | NinjaTrader Desktop (Windows) | Any browser, Mac included |
| Data setup | Download per instrument and date | None, history already loaded |
| Markets | CME futures and more, via your data feed | 105: index CFDs, forex, metals, energy, stocks, ETFs, crypto |
| Depth of market | Level II in replay data | None |
| Contract months and rollover | Real contracts | Continuous cash-index prices |
| Granularity | Tick by tick | 1-minute bars; ticks on Ultra for 20 symbols |
| History | What you download or record | Index daily bars from 2013, ticks from 2016 |
| Results | Performance in your sim account | Session report: win rate, expectancy, profit factor, drawdown |
NinjaTrader on Windows: connect data feed, download replay data, disconnect, connect to Playback. On a Mac add: install Parallels, install Windows, install NinjaTrader. Browser tool: pick a symbol, pick a start date.
Free market replay options
- NinjaTrader's own simulator. If you already have NinjaTrader Desktop and a data connection, Market Replay is the most realistic free-to-try option for futures.
- TradingView Bar Replay. Built into the charts you may already use, but the free plan limits which timeframes you can replay. See TradingView Bar Replay free limits.
- A browser replay simulator. FxBacktest lets you try bar replay without a card, on the same trading simulator used for forex, indices and stocks.
When to stay with NinjaTrader
Stay if you read the DOM or footprint charts, if your edge lives in specific CME contracts and their rollovers, or if your prop firm evaluation runs on NinjaTrader and you want to rehearse on the exact platform. No browser tool using index CFD prices replaces level II replay data.
Where FxBacktest fits
This is our product, so weigh this section accordingly. FxBacktest is a manual bar-replay simulator in the browser. For futures-style practice the relevant charts are the Nasdaq 100, S&P 500 and Dow Jones, plus the Russell 2000, with 13 timeframes from one minute to monthly. You pick a date, the chart hides everything after it, and you trade it forward with stops and targets dragged on the chart. Ultra adds tick replay on the Nasdaq, Dow and S&P 500, so a stop and target inside the same candle fill in the order the ticks printed.
The limits are the ones in the table: no depth of market, no contract months, no exchange volume. It is built for practising price action and trade management, and for traders who want the same tool for US stocks, forex and gold. Pro is €12 a month and Ultra €39; regional pricing can lower both.
Disclosure: FxBacktest is our own product. Its limitations are stated as plainly as everyone else's, and every NinjaTrader claim on this page links to its source.
Bottom line
NinjaTrader Market Replay is excellent when it is set up: real futures data, depth of market, tick by tick. Most "not working" problems come down to data and connections, and the checklist above fixes the common ones. If the downloads, contract months or the Windows requirement are what is in your way, a browser replay tool gets you practising today. For the wider field, see the best backtesting software, compared.
NinjaTrader Market Replay FAQ
How does NinjaTrader Market Replay work?
You download Market Replay data for an instrument and date in NinjaTrader Desktop, then connect to the Playback connection. A playback control window lets you play, pause and change speed, and you trade the replayed session on a simulation account as if it were live.
Why is my NinjaTrader Market Replay not working?
The usual causes are another connection still open (Playback needs every other connection closed), no replay data downloaded for that instrument and date, the wrong contract month, or corrupted data files. NinjaTrader staff also note you must be connected to your live data feed to download replay data, and cannot download it while connected to Playback.
Is NinjaTrader Market Replay free?
Market Replay is part of NinjaTrader Desktop and its simulation tools, but you need a data connection to download the replay data. Check NinjaTrader’s current licensing and your data provider’s terms, because both change.
What is the difference between Market Replay and NinjaTrader backtesting?
Market Replay is manual: you watch a past session unfold and place trades yourself. Backtesting in NinjaTrader usually means the Strategy Analyzer, which runs a coded NinjaScript strategy over historical data automatically.
Is there a Market Replay alternative that works on a Mac?
Yes. Browser-based replay tools such as FxBacktest run in Safari or Chrome with the history already loaded, so there is nothing to download. The trade-off is that they use index CFD prices rather than CME futures data with depth of market.
Sources
- NinjaTrader 8 help guide — Playback Connection — Market Replay vs historical tick data, and closing other connections first.
- NinjaTrader support forum — Market Replay data download — staff answers on the Historical Data window and the live-connection requirement.
- NinjaTrader support forum — Playback connection not working — troubleshooting thread.
- NinjaTrader 8 help guide — Strategy Analyzer — historical analysis of NinjaScript automated strategies.
- NinjaTrader — trading platform overview — "Log in to NinjaTrader Web from any PC or Mac browser", read 18 October 2026.