> ## Documentation Index > Fetch the complete documentation index at: https://docs.biconomy.io/llms.txt > Use this file to discover all available pages before exploring further. # Board feed > Every maker's board per block over a WebSocket, including boards signed but not yet onchain. Price the venue off-chain without reading it. 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 ```mermaid theme={null} sequenceDiagram participant M as Maker participant B as Biconomy participant C as Chain participant A as You M->>B: signs a new board B-->>A: boards: committed board + pending board B->>C: commits the new board C-->>B: next block B-->>A: boards: the new board, committed ``` * 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: ```json theme={null} { "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: ```json theme={null} { "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: ```text theme={null} 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](/propamm/aggregators/quickstart); the feed only replaces the reads. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.