Orderbook Stream - PolyNode

PolyNode’s Orderbook Stream delivers live orderbook snapshots, depth updates, and price changes for every active Polymarket market. Subscribe to the markets you care about and get enriched, human-readable data pushed to your connection in real time.

108,000+ markets

Every active Polymarket market is tracked. Subscribe to specific markets or get everything at once.

Enriched data

Snapshots include the event title, market question, outcome label, slug, and condition ID. Streaming updates include the slug and outcome for lightweight routing.

250ms batching

Updates are batched into 250ms windows for efficient delivery. One message per tick with all changes for your subscribed markets.

Compression included

Add &compress=zlib to your connection URL for ~50% bandwidth savings. Recommended for production.

Quick start

Get an API key

curl -s -X POST https://api.polynode.dev/v1/keys \
  -H "Content-Type: application/json" \
  -d '{"name": "my-app"}'

Save the pn_live_... key from the response.

Connect and subscribe

Subscribe using a condition ID or token ID from the REST API. Both sides of the market (Yes + No) are included automatically.

const ws = new WebSocket("wss://ob.polynode.dev/ws?key=pn_live_YOUR_KEY");

ws.onopen = () => {
  // Subscribe by condition ID — resolves to both Yes + No tokens
  ws.send(JSON.stringify({
    action: "subscribe",
    markets: ["0x7cb525e831729325d651017f81cbcb6f1adde5011c7b2283babea00b4ae93ae7"]
  }));
};

ws.onmessage = (event) => {
  const msg = JSON.parse(event.data);
  if (msg.type === "snapshot_batch") {
    for (const snap of msg.snapshots) {
      console.log(`${snap.question} [${snap.outcome}]: ${snap.bids.length} bids, ${snap.asks.length} asks`);
    }
  } else if (msg.type === "batch") {
    for (const update of msg.updates) {
      if (update.type === "price_change") {
        for (const asset of update.assets) {
          // size="0" means the level was removed; otherwise it's the new absolute size at that level.
          console.log(`${update.slug} [${asset.outcome}] ${asset.side} @ ${asset.price} -> size ${asset.size}  (bbo: ${asset.best_bid}/${asset.best_ask})`);
        }
      }
    }
  }
};

Use the REST API to find condition IDs: curl -s -H "x-api-key: pn_live_YOUR_KEY" "https://api.polynode.dev/v1/search?q=bitcoin" — each result includes the condition_id you can pass directly to the orderbook subscribe.

Receive data

You’ll immediately receive an orderbook snapshot for each subscribed token, then live batched updates:

{
  "type": "book_snapshot",
  "asset_id": "73624432805780182150964443951045800666977811185963019133914618974858599458273",
  "market": "0x561ffbf7de21ef3781c441f30536b026d2b301d7a4a0145a8f526f98db049ba2",
  "condition_id": "0x561ffbf7de21ef3781c441f30536b026d2b301d7a4a0145a8f526f98db049ba2",
  "event_title": "What price will Bitcoin hit in March?",
  "question": "Will Bitcoin reach $150,000 in March?",
  "outcome": "Yes",
  "slug": "what-price-will-bitcoin-hit-in-march-2026",
  "bids": [
    { "price": "0.001", "size": "8604930.58" },
    { "price": "0.002", "size": "4851192.42" }
  ],
  "asks": [
    { "price": "0.999", "size": "6152045.08" },
    { "price": "0.998", "size": "55007.54" },
    { "price": "0.997", "size": "5000" }
  ]
}

You can identify markets using any of these formats:

Firehose (all markets)
Slug (recommended)
Condition ID
Token ID

Subscribe to every active market with a single message. Pass "*" as the market identifier to get the full firehose (full data stream) of all 100,000+ tokens.

{
  "action": "subscribe",
  "markets": ["*"]
}

The server responds with "firehose": true and the total number of active tokens. Live updates start flowing immediately while snapshots stream in the background.

The simplest way to subscribe to specific markets. Use the slug from the Polymarket event URL. The server resolves it to all token IDs for that event (typically 2 per market, one for each outcome).

{
  "action": "subscribe",
  "markets": ["what-price-will-bitcoin-hit-in-march-2026"]
}

Use the hex condition ID for a specific market within an event. Resolves to the Yes + No token IDs for that market.

{
  "action": "subscribe",
  "markets": ["0x561ffbf7de21ef3781c441f30536b026d2b301d7a4a0145a8f526f98db049ba2"]
}

Use the raw CLOB token ID if you already have it. This matches Polymarket’s market identifier.

{
  "action": "subscribe",
  "markets": [
    "73624432805780182150964443951045800666977811185963019133914618974858599458273",
    "1666184515532238710431784265702709312060757077236443477960106115591255115343"
  ]
}

You can mix formats in a single subscribe:

{
  "action": "subscribe",
  "markets": [
    "what-price-will-bitcoin-hit-in-march-2026",
    "0xd1796c09d0d6f876f8580086ae9808ec991784e3a74b25a1830a25de71a78c96",
    "73624432805780182150964443951045800666977811185963019133914618974858599458273"
  ]
}

Finding markets

Use the PolyNode REST API to search for markets and find their slugs, condition IDs, or token IDs:

# Search by keyword
curl -s "https://api.polynode.dev/v1/search?q=bitcoin" | python3 -m json.tool

# Look up by slug
curl -s "https://api.polynode.dev/v1/markets/slug/what-price-will-bitcoin-hit-in-march-2026"

# Look up by condition ID
curl -s "https://api.polynode.dev/v1/markets/condition/0x561ffbf7de21ef3781c441f30536b026d2b301d7a4a0145a8f526f98db049ba2"

Or just grab the slug from any Polymarket event URL: polymarket.com/event/{slug}.

Connection URL

wss://ob.polynode.dev/ws?key=pn_live_YOUR_KEY

With compression (~50% bandwidth savings):

wss://ob.polynode.dev/ws?key=pn_live_YOUR_KEY&compress=zlib

Subscription limits

Use markets: ["*"] for the full all-market firehose. Explicit market lists are capped at 15,000 resolved token IDs per connection to protect low-latency fan-out; split large explicit watchlists across connections or use the firehose path when you truly need every market.

Tier	Connections	Explicit list cap	Firehose	Session limit
Free	1	15,000 tokens / connection	Included	1 hour/day
Starter ($50/mo)	10	15,000 tokens / connection	Included	Unlimited
Growth ($200/mo)	50	15,000 tokens / connection	Included	Unlimited
Enterprise ($750/mo)	Unlimited	15,000 tokens / connection	Included	Unlimited

Each Polymarket market has two tokens (one per outcome). Subscribing to both tokens of a market gives you the full two-sided orderbook. Plan upgrades increase the number of concurrent Orderbook Stream connections. The explicit-list token cap is a per-connection safety limit and is not removed by upgrading.

Free tier includes the full firehose. Subscribe to every market and see the full data flow. The only limit is a 1-hour daily session so you can properly evaluate the product before upgrading.

Orderbook connections are separate from event WebSocket connections. Your plan’s Event WebSocket limit applies to ws.polynode.dev; the limits above apply to the Orderbook Stream at ob.polynode.dev. Session time resets at midnight UTC.

Connection lifecycle

Firehose
Specific markets

Connect   -> wss://ob.polynode.dev/ws?key=pn_live_...
          <-  (connection established)

Send      -> {"action": "subscribe", "markets": ["*"]}
          <-  {"type": "subscribed", "firehose": true, "markets": 104972}
          <-  {"type": "batch", "ts": ..., "updates": [...]}         (live data starts immediately)
          <-  {"type": "snapshot_batch", "count": 50, "snapshots": [...]}  (snapshots stream in parallel)
          <-  {"type": "batch", ...}                                  (every 100ms)
          <-  {"type": "snapshot_batch", ...}                         (every 200ms)
          <-  {"type": "snapshots_done", "total": 67}
          <-  Ping frame                                              (every 30s)
          ->  Pong frame                                              (automatic)

Live updates start flowing immediately. You don’t have to wait for snapshots to finish. Snapshots are delivered in batches of 50 every 200ms for tokens that have active book data.

Connect   -> wss://ob.polynode.dev/ws?key=pn_live_...
          <-  (connection established)

Send      -> {"action": "subscribe", "markets": ["bitcoin-slug"]}
          <-  {"type": "subscribed", "markets": 4, "resolved_from": {"token_ids": 0, "slugs": 1, "condition_ids": 0}}
          <-  {"type": "snapshot_batch", "count": 2, "snapshots": [...]}
          <-  {"type": "snapshots_done", "total": 2}

          <-  {"type": "batch", "ts": ..., "updates": [...]}
          <-  {"type": "batch", ...}    (every 250ms when there are changes)
          <-  Ping frame                (every 30s)
          ->  Pong frame                (automatic)

Send      -> {"action": "unsubscribe"}
          <-  {"type": "unsubscribed"}

Separate from the main WebSocket

The Orderbook Stream runs on a separate endpoint (ob.polynode.dev) from the main PolyNode WebSocket (ws.polynode.dev). They are independent services:

	Main WebSocket	Orderbook Stream
Endpoint	`wss://ws.polynode.dev/ws`	`wss://ob.polynode.dev/ws`
Data	On-chain events (settlements, trades, blocks)	Off-chain orderbook (bids, asks, prices)
Timing	Pre-confirmation (pending + confirmed)	Real-time (live order placement/cancellation)
Use case	Trade detection, copy trading, alerts	Market making, pricing, depth analysis

You can connect to both simultaneously with the same API key.

108,000+ markets

Enriched data

250ms batching

Compression included

​Quick start

​Ways to subscribe

​Finding markets

​Connection URL

​Subscription limits

​Connection lifecycle

​Separate from the main WebSocket

Quick start

Ways to subscribe

Finding markets

Connection URL

Subscription limits

Connection lifecycle

Separate from the main WebSocket