SKILL.md

name	bitmex-fee-optimization
version	1.0.0
description	Minimize trading fees on bitmex-cli: maker vs taker, post-only orders, commission tiers, and fee audit.
metadata	openclaw requires depends category finance bins bitmex bitmex-shared bitmex-order-types

bitmex-fee-optimization

BitMEX charges taker fees and pays maker rebates. The difference is meaningful at scale. Default to limit orders with ParticipateDoNotInitiate for passive entries. For aggressive fills where immediate execution matters more than fee savings, use a limit order at the ask/bid price without this flag — see Avoid Market Orders below.

Fee Structure

Role	Fee Type	Direction
Maker	Rebate	You earn (negative fee)
Taker	Fee	You pay

Check your current fee schedule (returns a map of symbol → fees):

# All symbols
bitmex account commission -o json 2>/dev/null

# Single symbol
bitmex account commission -o json 2>/dev/null | \
  jq '.XBTUSD | {makerFee, takerFee, settlementFee}'

Default: Post-Only Limit Orders

ParticipateDoNotInitiate rejects the order if it would immediately match (become a taker). This guarantees the maker rebate or no fill at all.

# Post-only buy — earns rebate or does not fill
bitmex order buy XBTUSD 100 \
  --price 50000 \
  --order-type Limit \
  --exec-inst ParticipateDoNotInitiate \
  --validate -o json 2>/dev/null

bitmex order buy XBTUSD 100 \
  --price 50000 \
  --order-type Limit \
  --exec-inst ParticipateDoNotInitiate \
  -o json 2>/dev/null

# Post-only sell
bitmex order sell XBTUSD 100 \
  --price 50500 \
  --order-type Limit \
  --exec-inst ParticipateDoNotInitiate \
  -o json 2>/dev/null

Avoid Market Orders

Market orders always pay taker fees. Use limit orders at aggressive prices (inside the spread) instead:

# Instead of market buy, use aggressive limit:
ASK=$(bitmex market orderbook XBTUSD --depth 1 -o json 2>/dev/null | jq '[.[] | select(.side=="Sell") | .price][0]')
bitmex order buy XBTUSD 100 \
  --price "$ASK" \
  --order-type Limit \
  -o json 2>/dev/null
# Note: no ParticipateDoNotInitiate here — we want to take liquidity at ask

ImmediateOrCancel for Partial Maker

Fill at existing prices only, no remainder:

bitmex order buy XBTUSD 100 \
  --price 50000 \
  --order-type Limit \
  --tif ImmediateOrCancel \
  -o json 2>/dev/null

Volume Tier Review

Higher 30-day trading volume unlocks lower fees:

# Check your 30-day volume (returns array; first element has the totals)
bitmex account volume -o json 2>/dev/null | \
  jq '.[0] | {advUsd, advUsdContract, advUsdSpot}'

# Cross-reference with commission tiers (returns map of symbol → fees)
bitmex account commission -o json 2>/dev/null | jq '.XBTUSD'

Fee Audit from Trade History

# Sum fees paid over last 500 executions
bitmex execution trade-history --reverse --count 500 -o json 2>/dev/null | \
  jq '
    {
      total_fee: (map(.commission // 0) | add),
      total_volume: (map(.lastQty // 0) | add),
      trade_count: length,
      avg_fee_per_trade: ((map(.commission // 0) | add) / length | round / 100)
    }
  '

Maker vs Taker Split

bitmex execution trade-history --reverse --count 500 -o json 2>/dev/null | \
  jq '
    {
      maker_count: (map(select(.commission < 0)) | length),
      taker_count: (map(select(.commission > 0)) | length),
      maker_rebate: (map(select(.commission < 0) | .commission) | add // 0),
      taker_paid: (map(select(.commission > 0) | .commission) | add // 0)
    }
  '

Validate Order Role Before Submission

# --validate returns the expected execInst, confirming post-only
bitmex order buy XBTUSD 100 \
  --price 50000 \
  --order-type Limit \
  --exec-inst ParticipateDoNotInitiate \
  --validate -o json 2>/dev/null | \
  jq '{ordType, execInst, price}'

If execInst in the validate response does not include ParticipateDoNotInitiate, do not submit.