short orders

[NINJA0423]

Hi, I’m building a simple TradingView → Flask → Lighter bot using SignerClient, and I’m confused about how to correctly send short orders and long closes via create_market_order.

Right now:

• Open long works 100% of the time.

• Close short works when there is an actual short position.

• However:

  • When I try to open a short, the order appears in the UI but is always Canceled with filled = 0.
  • When I send a “close short” while I have no short position, it opens a new long instead of doing nothing.
  • In my tests, the other 2 patterns (open short / close long) end up canceled.

On the backend I’m always using create_market_order (I don’t use limit orders).
My TV → bot signal looks like this:

{
  "account_id": "default",
  "symbol": "BTCUSDT",
  "side": "sell",              // or "buy"
  "size_usd": 100.0,
  "price": 87413.54,           // TradingView price, NOT sent to Lighter
  "order_type": "open",        // "open" or "close"
  "is_new_entry": true,
  "is_close": false,
  "raw": { ... original webhook ... }
}

Then I convert it to Lighter params like this:

symbol = "BTC"  # from "BTCUSDT"
mconf = MARKET_CONFIG[symbol]   # {"market_index": 1, "size_decimals": 5}
market_index = mconf["market_index"]
size_decimals = mconf["size_decimals"]

# USD size → base_amount_int
base_amount_human = size_usd / price
base_amount_int = round(base_amount_human * 10**size_decimals)

is_ask = (side == "sell")              # buy = bid, sell = ask
reduce_only = bool(is_close)           # close -> True, open -> False

client_order_index = int(time.time() * 1000)

result = await client.transactions.create_market_order(
    market_index=market_index,
    base_amount=base_amount_int,
    client_order_index=client_order_index,
    is_ask=is_ask,
    reduce_only=reduce_only,
)

So my mapping is:

• Open long: side="buy", is_ask=False, reduce_only=False
• Close long: side="sell", is_ask=True, reduce_only=True
• Open short: side="sell", is_ask=True, reduce_only=False
• Close short: side="buy", is_ask=False, reduce_only=True

From the Python side the API call returns code=200 and looks OK, but on the UI the open short and close long orders show as Canceled with filled = 0.

Could you please confirm:

1. Is this is_ask / reduce_only mapping correct for:

   • open long
   • close long
   • open short
   • close short

2. Is there any extra parameter or flag required for short market orders or long close with reduce_only?

3. Under what conditions would create_market_order return success but the order be immediately canceled with filled = 0 on the UI?

I’ve attached screenshots and log snippets showing one successful long open & close, and a canceled short open with the corresponding debug fields if that helps.

[NINJA0423]

I’m running a small Python trading bot on Lighter mainnet using the official lighter Python client.

Market: BTC

Side: LONG open / LONG close / SHORT open / SHORT close

Order type: market only (no limit orders, no TWAP, no grouped orders)

Symptom

LONG opens always fill 100% from my bot.

All of the following orders are “accepted” by the API (I get code=200 and a tx hash), but do not change my position on BTC:

SHORT opens (sell to open)

LONG closes (sell to close – reduce-only)

SHORT closes (buy to close – reduce-only)

There are no open orders left after the transaction.
On the UI, most of these orders show up as canceled.

If I close the position manually in the UI with the same size, it fills immediately.

Logs from my bot

Example LONG open (this one works):

lighter_params: {
'market_index': 1, # BTC
'base_amount': 115,
'avg_execution_price': 8704961,
'is_ask': False,
'reduce_only': False
}

Example LONG close (does not work, position remains open):

lighter_params: {
'market_index': 1,
'base_amount': 115,
'avg_execution_price': 8707025,
'is_ask': True,
'reduce_only': True
}

The tx is accepted:

RespSendTx(code=200, message='{"ratelimit": "didn't use volume quota"}', tx_hash='...')

but the BTC position size doesn’t change at all.

The same pattern happens for:

SHORT open (is_ask=True, reduce_only=False)

SHORT close (is_ask=False, reduce_only=True)

What I already checked

base_amount exactly matches the position size (e.g. 0.00115 BTC → base_amount_int=115).

market_index is correct for BTC (1).

Slippage guard: when my Python wrapper detects “excessive slippage”, it falls back to a plain create_market_order() without any guard. Even then, the BTC close orders still don’t affect the position.

On ETH, the same logic appears to work as expected.

Questions

On mainnet BTC, are there any known issues or restrictions with:

reduce-only market orders, or

closing positions via create_market_order / create_market_order_if_slippage from the Python client?

In the TypeScript SDK, I see that close_position.ts uses:

const [tx, txHash, closeErr] = await client.createMarketOrder({
marketIndex,
clientOrderIndex,
baseAmount,
avgExecutionPrice,
isAsk: isLong, // sell to close long, buy to close short
reduceOnly: true, // close-only
})

What is the exact equivalent of this pattern in the Python SignerClient?

Is there any BTC-specific behavior on mainnet that would cause:

LONG opens to fill normally, but

all SHORT / reduce-only market orders to be silently canceled on the matching engine?

I can provide full Python snippets and more logs if needed.
For now I just want to know if I’m hitting a known limitation/bug on BTC, or if I should change how I construct close orders in Python.

[NINJA0423]

Thanks a lot for your help earlier with debugging the orders.
I applied the price * 0.99 adjustment on sell orders, and now long/short opens and closes are all going through fine.
The problem was my side (price too aggressive against your checks), not Lighter itself.
I really appreciate you taking the time to explain how it works and sticking with me through the tests 🙏