L4 Order Book

import websockets, json, asyncio

async def stream_l4():
    uri = "wss://api.0xarchive.io/ws?apiKey=YOUR_KEY"
    async with websockets.connect(uri, max_size=20_000_000) as ws:
        # Subscribe to L4 diffs (works for l4_diffs or hip3_l4_diffs)
        await ws.send(json.dumps({
            "op": "subscribe",
            "channel": "l4_diffs",
            "symbol": "BTC"
        }))

        book = {"bids": {}, "asks": {}}
        snapshot_ts = None

        async for msg in ws:
            data = json.loads(msg)

            if data["type"] == "l4_snapshot":
                # Full book delivered first (every order including triggers)
                snapshot_ts = data["timestamp"]
                for order in data["data"]["bids"]:
                    book["bids"][order["oid"]] = order
                for order in data["data"]["asks"]:
                    book["asks"][order["oid"]] = order
                print(f"Snapshot: {len(book['bids'])} bids, {len(book['asks'])} asks")

            elif data["type"] == "l4_batch" and snapshot_ts is not None:
                # Apply diffs to maintain the book
                for diff in data["data"]:
                    if diff["ts"] <= snapshot_ts:
                        continue
                    side = "bids" if diff["side"] == "B" else "asks"
                    oid = diff["oid"]
                    if diff["dt"] == "new":
                        book[side][oid] = {
                            "oid": oid, "side": diff["side"],
                            "price": diff["px"], "size": diff["sz"],
                            "user_address": diff["user"]
                        }
                    elif diff["dt"] == "update":
                        if oid in book[side]:
                            book[side][oid]["size"] = diff["sz"]
                    elif diff["dt"] == "remove":
                        book[side].pop(oid, None)

asyncio.run(stream_l4())