How TradingView Simulates Order Fills: Broker Emulator and Bar Magnifier

A strategy marker records a simulated Broker Emulator fill

A TradingView strategy creates order commands, then the Broker Emulator simulates a fill on the next available tick or when a price condition becomes eligible. The condition bar, order-creation time and visible fill marker need not be identical. Reconcile order type and creation bar with the List of Trades instead of reading the marker alone.

This is a repeatable historical simulation, not automatic recovery of the broker’s queue, spread, latency, rejection, partial fills or price improvement. A Tester fill at 104 is not proof that a live account would have received 104 at that time.

An OHLC history requires an assumed intrabar path

OHLC identifies four points reached during a bar but not every tick between them. The Broker Emulator applies documented rules to infer an open-high-low-close or open-low-high-close path. When both entry and exit levels sit inside one range, this ordering can change whether an exit was reachable after entry.

A touched price does not prove sufficient liquidity for the entire order in a real market.

Separate four failure boundaries. A price touched before the order existed is not fill evidence. A gap between the prior close and next open does not prove that every intermediate level traded. A bar containing both entry and exit prices still needs an after-entry path. A limit order also requires its current verification rule and active lifetime, not merely a visible touch.

Separate market, limit, stop and stop-limit behavior

A market order asks for execution at the next available opportunity without a target price. A limit constrains the acceptable price. A stop activates after its trigger and then behaves as its defined order type. A stop-limit adds a limit condition after activation. A chart touching a line therefore means different things for each order.

Confirm current behavior in TradingView’s official Strategies and Broker Emulator documentation.

A close-confirmed strategy that creates a market order can display its fill around the next bar’s open under standard behavior. Explain this as condition confirmation, creation, then next available tick—not merely as a “late signal.”

Use lower-timeframe detail, then measure its actual coverage

Bar Magnifier lets the emulator consult available lower-timeframe data instead of relying only on the chart bar’s default path. If lower-timeframe bars show an entry followed by an exit level inside one chart bar, a same-bar exit can appear where the default path did not allow one.

Lower-timeframe requests have a historical limit, so early portions of a long chart can lack coverage. Plan, symbol, chart interval and available lower intervals matter too. Record not just that Magnifier was enabled, but which audited trades were actually inside its covered region.

Coverage proves the granularity behind a simulated fill, not the fill that a live venue would have delivered.

Make the order type and Magnifier premise visible in source

The Pine v6 sample creates a fictional buy stop after a confirmed cross and, after a position exists, places stop and limit exits. `use_bar_magnifier = true` records the intended premise, but feature availability and historical coverage still require an environment check. The EMA and tick distances are teaching values, not recommended orders.

//@version=6
strategy(
    "Intrabar fill audit demo",
    overlay = true,
    use_bar_magnifier = true,
    calc_on_order_fills = false,
    process_orders_on_close = false
)

float basis = ta.ema(close, 20)
bool setup = ta.crossover(close, basis) and barstate.isconfirmed

if setup
    float entryStop = high + syminfo.mintick
    strategy.entry("L", strategy.long, stop = entryStop)

if strategy.position_size > 0
    float protectiveStop = strategy.position_avg_price - 10 * syminfo.mintick
    float target = strategy.position_avg_price + 20 * syminfo.mintick
    strategy.exit("L-X", "L", stop = protectiveStop, limit = target)

plot(basis, "EMA", color.orange)

Source alone still cannot explain every fill. Reconcile the List of Trades entry/exit bar and price with chart OHLC, coverage and order-creation evidence. If `calc_on_order_fills` or `process_orders_on_close` changes, pair the comparison with TV15’s execution audit.

Try to falsify the surprising fills one trade at a time

Keep an unexplained field visible instead of inventing a tick path.

Start with assumption-sensitive trades: same-bar entry/exit, gaps, a limit touched once and the early history of a long dataset. Preserve versions whose performance deteriorates; they reveal which results depended on optimistic fill assumptions.

Freeze a window containing the target trades, run the default-path version, then rerun with Bar Magnifier under the same source hash and Properties. Export the same trade-list format from both and reconcile from the first diverging ID. Reopen the same chart context on another date and confirm that coverage start, creation time and fill price still support the same explanation. Use unresolved and uncovered counts as the release gate rather than selecting the more profitable run.

Audit fills before sending result data to the Lab

Once every challenged fill has an explanation and the Bar Magnifier coverage is recorded, open the Backtest & Robustness Lab with the matching fill-audit export in CSV or XLSX format. Compare equity paths, drawdowns and trade distributions across Magnifier-off, Magnifier-on and conservative-fill fingerprints. Paid saved analysis becomes useful when those like-for-like fill versions must remain available for repeated comparison.

Free indicators can support signal observation, but an indicator does not automatically generate strategy orders or Tester trade data. Define the order rules in a strategy and finish the fill audit first. Bar Replay, Paper Trading and the Broker Emulator expose different limitations rather than replacing one another.