For Web
Switch Mode lives in the trading terminal preferences on BitMEX Web. Open the BitMEX trading terminal and select the contract you want to trade. Click the preferences icon in the top-right corner of the trading interface.
Find the Position Mode setting in the Trading section. Select either Hedge Mode and confirm the change.
Open positions carry over into the new mode: a 10 BTC long in One-Way Mode appears as a 10 BTC long leg in Hedge Mode after the switch, ready for an independent short entry against the same contract. The positions panel updates immediately to reflect the new mode. Traders moving from Hedge Mode back to One-Way Mode will see long and short legs consolidate into a single net position on the trading panel.
For Mobile
Switch Mode is available in the BitMEX mobile app under trading settings. Open the BitMEX app and navigate to the trading screen for the contract you want to trade. Tap the settings icon in the top-right corner.
Select Position Mode from the menu. Choose One-Way Mode or Hedge Mode and confirm.
Open positions carry over into the new mode on mobile in the same way as web: the position keeps its entry price, P&L, and margin, and displays under the new mode in the positions tab. Traders can also reach the Position Mode control from Account, then Preferences, then Position Mode. Switch Mode on mobile triggers the same account-level change as the web switch, so a trader who flips on mobile will see the new mode reflected on web and via the API immediately.
For API
Switch Mode is available via the BitMEX API's position mode endpoint. The request takes an account-level mode parameter (hedge or oneway) and applies the switch to open positions without requiring them to be closed first.
For the exact endpoint path, request signature, authentication headers, and example payloads, see the BitMEX API documentation: https://www.bitmex.com/api/explorer/