Supported orders
- Market — matched against the top of book, guaranteed execution, price uncapped.
- Limit — resting order at a specified price, GTC by default, IOC and FOK available.
- Stop — triggered on mark price crossing the stop level, then routes as Market or Limit.
- Reduce-only — cannot open or flip a position, only reduce it (safe for TP / SL legs).
- Post-only — rejected if it would cross the book (maker-only entry).
Nonces and deduplication
Every order carries a monotonically increasing nonce scoped to the session key. The matching engine drops any duplicate. On reconnect the client should resume from the last acknowledged nonce, not from zero.