I’m struggling with data inconsistencies in my trading setup and need some guidance.
I purchased forex market data from a third-party provider and integrated it into my backtesting platform. When I validate this data against charts from popular trading platforms, I notice some concerning patterns.
For longer timeframes like 4-hour candles, the data matches pretty well across different sources. However, when I drill down to shorter intervals like 5-minute or 15-minute bars, I see major discrepancies. The candle wicks show different highs and lows, and sometimes a green candle on one platform appears red on another.
def compare_market_data(source_a, source_b, timeframe):
differences = []
for i in range(len(source_a)):
bar_a = source_a[i]
bar_b = source_b[i]
high_diff = abs(bar_a.high_price - bar_b.high_price)
low_diff = abs(bar_a.low_price - bar_b.low_price)
if high_diff > 0.0005 or low_diff > 0.0005:
differences.append({
'timestamp': bar_a.time,
'high_variance': high_diff,
'low_variance': low_diff
})
return differences
This makes me worried about developing strategies based on candlestick patterns since they might only work with one specific broker’s feed.
My main concerns are:
- How do professional traders handle these data variations?
- Does this mean I’m stuck using only one broker’s data for both testing and live trading?
- Are third-party data services not reliable for serious trading development?
Third party data works for learning but it’s useless for actual strategies. Always match your backtest data with what your live broker provides.
Data differences between brokers are normal because forex is decentralized. Each broker gets quotes from different sources, leading to variations, especially in shorter timeframes. For backtesting, always use your broker’s data. Most brokers provide historical data through MT4/MT5 or APIs. This allows you to test on the same feed you will trade on, avoiding surprises when you go live. Third-party data can work for longer timeframes or general analysis, but for precise entry and exit strategies, stick to the data your real trades will use.
Use your broker for five minute data.
Pip differences on short timeframes happen because brokers pull quotes from different liquidity providers at different times.
Found this out the hard way. Backtests looked perfect but live trading was a mess. Now I just grab historical data straight from my broker instead of using outside feeds.
Most platforms let you export data easily. This saves you from getting burned when you go live.
Same reason I ditched third-party feeds years ago. It’s not just the pip differences - it’s the timing that kills you. News events hit brokers at different moments, so your backtests show fake signals. Try this: pull data from NFP or central bank announcements and compare. Third-party feeds smooth out the chaos that actually happens in live markets. Just download historical data straight from your broker’s platform. Most have export functions or APIs. Your backtests will actually match the slippage and spread widening you’ll see when trading live.
Your code’s tracking the right stuff. Those 0.5 pip differences are massive for short-term strategies.
Hit this exact problem 3 years back building a 5-minute breakout system. Third-party data showed 80% win rate in backtests. Live trading with OANDA? Total disaster.
Gets worse during news and market opens. Different liquidity providers go crazy with spreads for a few seconds, and third-party feeds miss those spikes completely.
Now I pull everything straight from my broker’s MT4 history center. Takes longer to set up but my backtests actually match reality.
One trick - if you’re testing multiple brokers, grab small live data samples from each during different market conditions. You’ll see which feeds are cleanest before risking real money.
Stick with one broker for shorter timeframes.