Two charts of the "same" market rarely match exactly, and the differences are structural rather than errors. Knowing which one applies matters, because some are harmless and one will wreck a backtest.
1. Different data sources
The symbol on your chart comes from a specific exchange, broker or aggregated feed. Your execution platform quotes its own liquidity. In decentralised markets like spot forex and crypto there is no single official price, so two feeds legitimately differ by small amounts all day.
Check the exchange name next to the symbol. Where your broker's feed is available on the platform, selecting it removes most of the discrepancy.
2. Bid vs ask vs last
Charts typically plot the last traded price or the bid. Your platform may quote the ask when you buy. The gap between them is the spread, and it is not an error — it's the cost of crossing.
This alone explains most small differences in forex and crypto.
3. Delayed data
Without a real-time subscription for that exchange, your chart shows delayed data. In fast conditions a delayed chart and a live platform will disagree substantially. The delay status appears near the symbol.
4. Session settings
Extended-hours trading, different session open and close times, and different timezone settings all change what a candle contains. A daily candle built from 24-hour data is a different candle from one built from a regular session, even from the same feed.
Check chart settings → Symbol → session, and confirm the timezone at the bottom right of the chart.
5. Contract rollover in futures
Continuous futures symbols stitch contracts together, and the method used to join them changes historical prices. Your broker showing a specific contract month will not match a continuous chart in the history, even though the current price agrees.
