Board feed

The board feed sends every maker’s board on each block, the same boards board() returns onchain. When a maker signs a new board, the feed sends it right away, before it lands onchain, so you can price the next block’s book without reading the venue.

Environment	Stream	Snapshot	Chains
Staging	`wss://propamm-staging.biconomy.io/venue-stream`	`GET https://propamm-staging.biconomy.io/v1/venue/boards?chainId=84532`	Base Sepolia (84532)
Production	`wss://propamm.biconomy.io/venue-stream`	`GET https://propamm.biconomy.io/v1/venue/boards?chainId=8453`	Base (8453)

Send your API key in the x-api-key header, on the WebSocket connection request and on REST. Ask us for a key.

How it works

On every new block you get a message with every maker’s boards at that block.
When a maker signs a new board, you get a message at once, with the new board marked committed: false.
Every message is a full snapshot of the venue. There is nothing to merge, and a missed message is repaired by the next one.

Stream

Connect, then subscribe to a chain:

{ "type": "subscribe", "chainId": 8453 }

You send	Reply
`{"type":"subscribe","chainId":8453}`	`{"type":"subscribed","chainId":8453}`, the latest snapshot, then every new one
`{"type":"unsubscribe","chainId":8453}`	`{"type":"unsubscribed","chainId":8453}`
`{"type":"ping"}`	`{"type":"pong"}`

Errors arrive as {"type":"error","code":"...","message":"..."}, with code one of RATE_LIMITED, INVALID_JSON, INVALID_MESSAGE or UNSUPPORTED_CHAIN. The server pings every 15 seconds and closes connections that miss a pong. Ignore message types you do not know; new ones may be added.

Snapshot over REST

GET /v1/venue/boards?chainId=8453 returns the latest message, the same JSON the stream sends, or 503 with Retry-After while the feed starts. The feed runs while someone reads it: after 30 seconds without a subscriber or a request it stops, and the next request starts it within about 5 seconds. Poll every few seconds, or hold a stream subscription, to keep it running.

Message

An example, with one of the boards on Base at block 52847598:

{
  "type": "boards",
  "chainId": 8453,
  "venue": "0x0000009E5F98cDB4dd1E1d2E15B220217c88B3b8",
  "executor": "0x0000006f9bBA066e4efda2e0CAbE4FF8cf9030aC",
  "blockNumber": "52847598",
  "timestamp": "1792484543",
  "nextTimestamp": "1792484545",
  "feeBps": 0,
  "makers": ["0x960f1e3181E928210C02a34EE29bf3d354dD2FF5", "0x72A2df03AeeF2A8343f9Fb86bd65193A3008890C"],
  "boards": [
    {
      "mm": "0x72A2df03AeeF2A8343f9Fb86bd65193A3008890C",
      "tokenIn": "0x4200000000000000000000000000000000000006",
      "tokenOut": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "committed": true,
      "lastCommitBlock": "52847598",
      "mode": "prices",
      "sizes": ["645755065000000", "1291510130000000", "1937265195000000", "2583020261000000"],
      "prices": ["2385958388", "2385719769", "2385481149", "2385242529"],
      "filled": "0",
      "remaining": "645822708000000",
      "expiresAt": "1792484548",
      "depthNonce": "1792484540974",
      "anchorNonce": "0",
      "controlsNonce": "1792483363"
    }
  ],
  "builtAtMs": 1792484543150
}

Here WETH has 18 decimals and USDC 6, so 2385958388 is 2,385.958388 USDC per WETH. remaining is below the board’s depth because the maker’s per-block cap is smaller.

Field	Meaning
`blockNumber`, `timestamp`	the block every committed board was read at, and its timestamp in unix seconds; committed boards are priced for it
`nextTimestamp`	the next block’s timestamp, from the last two blocks’ spacing; pending boards are priced for it, since that is the earliest block they land in
`feeBps`	the venue’s protocol fee: `out - out * feeBps / 10000` on the merged output
`makers`	registered makers in registry order; the venue breaks price ties in this order
`builtAtMs`	when the message was built, unix milliseconds; use it to detect a stale feed

Each entry of boards:

Field	Meaning
`mm`, `tokenIn`, `tokenOut`	maker and direction
`committed`	`true`: the board onchain at `blockNumber`; `false`: signed, not yet onchain
`lastCommitBlock`	block of the board’s last commit; `null` when pending
`mode`	`prices`, `offsets` or `none`
`sizes`	cumulative `tokenIn` amounts, one per level
`prices`	`tokenOut` per `1e18` `tokenIn` at each level, after drift, widening and premium
`filled`	`tokenIn` already filled from this board; fills continue from here
`remaining`	most `tokenIn` the board takes in one block: depth left, per-block cap and maker inventory, whichever is smallest; `0` when dark
`expiresAt`	unix seconds; dark after it
`depthNonce`, `anchorNonce`, `controlsNonce`	versions of the board’s signed parts, for change detection

Integers are decimal strings. A dark board (maker paused, expired, or its inventory contract no longer names the maker) has no levels and remaining 0. A direction a maker has never quoted is not listed.

Price a swap

One board, sweeping from filled, exactly as the venue does:

out = 0; cursor = filled; left = amountIn            // amountIn <= remaining
for each level i:
    if cursor >= sizes[i]: continue
    take = min(sizes[i] - cursor, left)
    out += take * prices[i] / 1e18                     // round down, per level
    cursor += take; left -= take
    if left == 0: break

Across makers, take the best next level first, ties in makers order, and stop each maker at its remaining. Drop an allocation whose output rounds to zero. Then take the protocol fee off the total. quote() onchain runs the same steps, so you can check your implementation against it at blockNumber.

Committed or pending

A pending board lands onchain shortly after the maker signs it. On Base, 299 sampled commits from 20 October 2026 all landed within 3 seconds of signing (median 2.1 seconds), so one to two blocks.

Your swap lands	Price with
a few seconds after you quote, for example a route a user signs in a wallet	the pending board when there is one
in the very next block, and the quote must hold either way	the lower output of the committed and the pending board, per maker

If a commit fails, the pending board disappears from the next message and the committed board stays. A board without a pending entry has nothing waiting.

Time

Committed prices are for timestamp and pending prices for nextTimestamp. Prices move between blocks without a new board:

an offsets board’s price falls as its anchor ages;
a board with widening falls with the square root of its age;
a board with a premium is priced lower for a few blocks after each commit, then rises when the premium ends.

Use the newest message and treat one whose builtAtMs is more than a few seconds old as stale. To execute, call the venue as in Integration; the feed only replaces the reads.

Getting Started

Market Makers

Aggregators

Reference

How it works

Stream

Snapshot over REST

Message

Price a swap

Committed or pending

Time

​How it works

​Stream

​Snapshot over REST

​Message

​Price a swap

​Committed or pending

​Time

How it works

Stream

Snapshot over REST

Message

Price a swap

Committed or pending

Time