API reference, Builder codes

Builder

One builder code: totals and rank, day by day, per market, order outcomes and fee rates.

GET https://api.femtos.xyz/v1/hypercore/builders/{builder}

Parameters

Param	In	Example or values	Meaning
`builder`	path	`0xb84168cf3be63c6b8dad05ff5d755e97432ff80b`	Builder address (0x), as orders name it in `builder.b`
`window`	query	`(empty)`, `24h`, `7d`, `30d`, `90d`, `all`	Window, whole hours ending with the current one: 24h, 7d, 30d, 90d, or all (since 2025-07-19)

curl -H "Authorization: Bearer $FEMTOS_KEY" "https://api.femtos.xyz/v1/hypercore/builders/0xb84168cf3be63c6b8dad05ff5d755e97432ff80b?window=30d"

Key: Authorization: Bearer $FEMTOS_KEY. Get a free key, or with no browser through agent onboarding.

Field	Type	Meaning
`total`	object	Over the window: {fees, feesByToken, volume, fills, takerFills, users, feeRate, feeShare, orders}
`rank`	int \| null	Rank by fees among every builder in the window; null with no fill in it
`daily[]`	object	UTC days of the window with a fill, oldest first: {day, fees, volume, fills, users}
`markets[]`	object	Its markets, most fees first (100 at most): {coin, quote, fees, volume, feeRate, fills, users}
`orders`	object \| null	Its order statuses in the window; null for a window ending before order coverage: {orders, byStatus, feeRates}
`orders.byStatus[]`	object	Most first: {status, events, orders}
`orders.feeRates[]`	object	Most orders first: {feeTenthsBp, orders}

Builder leaderboard GET /v1/hypercore/builders HyperCore
Every builder code ranked by fees, volume, users or orders, over 24 h to all time.
Builder orders GET /v1/hypercore/builders/{builder}/orders HyperCore
Every status of the orders sent with one builder code, rejections and their reasons included.
Builder orders stream WS hc.builder.orders HyperCore
Every status of the orders sent with one builder code as it happens, rejections and their reasons included. One frame per block with all its matching events.
Builder fills GET /v1/hypercore/builders/{builder}/fills HyperCore
Every fill of one builder code, with its builder fee, oid, tid and hash.
Builder fills stream WS hc.builder.fills HyperCore
Every fill of one builder code as it happens, with its builder fee: the rows of the builder fills route, pushed per block. One frame per block with all its matching events.