Myth vs rule on MEXC: selling to hedge in One-Way Mode just offsets your long

The position-mode rule

On MEXC futures, Position Mode sits in Preferences. Web and App both route through Futures preferences to pick Hedge Mode or One-Way Mode. If any order or position is open, the switch is locked until you cancel and flat.

Ticket checklist before the first fill

1. Open Futures preferences and read the current Position Mode line.
2. Choose One-Way Mode for a single net direction, or Hedge Mode when you need both sides.
3. Flat the book and cancel resting orders before you flip the mode.
4. Set margin mode (isolated or cross) and leverage L on the ticket after the mode is set.
5. In Hedge Mode, use the open-long / open-short / close controls as separate actions. An opposite order in One-Way Mode offsets or flips instead.
6. When you mention fees on the same ticket, remember MEXC futures fees vary by region. The SOL_USDT contract detail API returned maker 0 and taker 0.0002 (0.02%) as the default special rate at fetch time; selected regions can differ, so read your own fee panel.

Worked steps

1. Flat account: set Position Mode to Hedge Mode.
2. On SOL_USDT, note contractSize 0.1 from the contract detail endpoint (qty is in contracts; notional scales with contract size x mark).
3. Open long with size qty contracts at leverage L.
4. Open short separately on the same pair. Both rows should remain visible under Hedge Mode.
5. Close only the long with the close-long path. The short should remain.
6. Repeat the mental test in One-Way Mode on a tiny size: an opposite order reduces or flips the single net position.

Formula

one_way_net = signed_size on pair hedge_book = {long: size_long, short: size_short} fee_leg = notional x account_fee_rate (region-specific on MEXC)

What changes it

• Hedge Mode needs margin for both sides, so capital use rises when both legs are open.
• Leverage mode (simple vs advanced) can keep long/short leverage and margin mode aligned or separate. That is a preferences sibling of Position Mode.
• Price Protection and other ticket guards are separate toggles. This piece is Position Mode only.
• Regional fee rows can change the cost of the same ticket path without changing the mode rule.

Common mistakes

1. Hedging from One-Way Mode and wondering where the long went.
2. Trying to switch modes with a trigger order still armed.
3. Opening both sides in Hedge Mode without checking shared or isolated margin headroom.
4. Reading a friend's fee screenshot as your rate. MEXC fees vary by region.
5. Mixing contract count with coin size on SOL_USDT when contractSize is 0.1.

FAQ

Which mode should a first futures order use? Beginners usually start on One-Way Mode for simpler direction management.

Does Hedge Mode cost more in fees? Not by itself. Fees follow maker/taker and your regional schedule. Hedge costs more margin when both sides are live.

Can I change modes mid-trade? Not while positions or orders exist. Flat first.

Where do I see contract size? Contract detail for the symbol lists contractSize. For SOL_USDT it read 0.1 at the fetch used here.

Next time you size a trade

Set Position Mode before size on MEXC: One-Way nets, Hedge keeps both sides, and the fee line on that same ticket still needs your regional panel.

Keep the fee panel and the Position Mode line in the same glance before you send. Mode mistakes close size; regional fee mistakes only change the bill, but both start on the same ticket.

Contract size is easy to misread when you are used to coin-denominated tickets, so convert qty to notional before you set L.