Short answer: TradingView’s Strategy Tester and an exchange’s native backtesting tool often produce different results for the same strategy because they use different historical data, fee assumptions, and fill models. Comparing both exported trade histories — and auditing each independently — is how you find out which assumptions actually hold before risking capital.
Two backtesters, two sets of assumptions
As more exchanges ship their own in-house backtesting tool, algo traders increasingly have a choice: test a strategy in TradingView’s Strategy Tester, in the exchange’s native tool, or both. The two rarely agree exactly on the same strategy — and that disagreement is informative, not just noise.
TradingView tests against its own aggregated historical data across whichever symbol and exchange feed you’ve selected, using a fee and slippage model you configure yourself. An exchange-native backtester, by contrast, usually tests against that specific venue’s own order book history and applies its own default fee schedule — which may or may not match what you’d actually pay.
Where the two tools typically diverge
Three areas account for most of the gap: historical data source (different providers can have different gaps, different bar timestamps, or different handling of exchange outages), fill model (bar-close approximation vs. tick-level or order-book simulation), and default commission assumptions (a generic 0.1% taker fee in one tool vs. the exchange’s actual tiered fee schedule in the other).
None of these differences make one tool ‘wrong’ — they make the two outputs not directly comparable without checking what each one assumed. A strategy that looks profitable in one and marginal in the other is telling you exactly where to look.
Comparing both exported trade histories side by side
Both TradingView’s ‘List of Trades’ export and most exchange-native testers offer a CSV or similar export of every simulated trade. Lining these up — same strategy, same date range, same symbol — surfaces the assumption gap directly: entry/exit prices, commission per trade, and win rate can all be compared row by row instead of just eyeballing two different equity curves.
This is also where an independent audit earns its keep: rather than trusting whichever tool gave the more flattering number, running both exports through the same auditing process applies one consistent standard to both, instead of two different vendor defaults.
Pick the tool that matches where you’ll actually trade
If you’re trading exclusively on one exchange, that exchange’s native backtester has an edge: it tests against the same order book and fee schedule you’ll face live. If you trade across multiple venues or symbols not covered by a single exchange’s tester, TradingView’s broader data coverage and Pine Script flexibility usually wins.
Either way, the same rule applies: the exported trade history — not the summary equity curve — is what should decide whether a strategy is ready for real capital.