Real-Time Websocket Streams with polymarket-client

Subscribe to live order book updates, user order events, sports scores, and RTDS feeds using the unified subscribe() API in polymarket-client.

Polymarket exposes a WebSocket server that pushes real-time updates for order books, your own order activity, sports scores, and RTDS data feeds. The polymarket-client SDK wraps all of these behind a single subscribe() call that returns an async stream — you iterate it with standard futures::StreamExt combinators and close it with a single method call when you are done.

Enable the websockets feature

WebSocket support is gated behind the websockets feature flag. Add it to your Cargo.toml:

polymarket-client = { version = "0.1", features = ["websockets"] }

The secure feature bundle already includes websockets, so if you have features = ["secure"] you can skip this step.

Subscribe to the market channel

The market channel streams live order book events, price updates, and last-trade data for one or more outcome tokens. You call subscribe() on PublicClient, passing a Vec of SubscriptionSpec values:

use futures::StreamExt as _;
use polymarket_client::{
    Environment, MarketSubscription, PublicClient, SubscriptionSpec,
};

let client = PublicClient::new(Environment::production());

let mut handle = client.subscribe(vec![SubscriptionSpec::Market(MarketSubscription {
    token_ids: vec!["TOKEN_ID".into()],
    custom_feature_enabled: false,
})])?;

while let Some(event) = handle.next().await {
    println!("{event:?}");
}
handle.close();

handle implements futures::Stream, so you can use .next(), .take(), .filter_map(), and the rest of the StreamExt API. Call handle.close() when you no longer need updates to cleanly shut down the underlying WebSocket connection.

Subscribe to the user channel

The user channel delivers real-time events scoped to your own wallet — order placements, fills, and cancellations. Because the server must verify your identity before opening this channel, you must call subscribe() on a SecureClient rather than a PublicClient:

User subscriptions require a SecureClient. Calling subscribe with SubscriptionSpec::User on PublicClient will return an error at runtime.

use polymarket_client::{SubscriptionSpec, UserSubscription};

let mut handle = secure.subscribe(vec![SubscriptionSpec::User(UserSubscription {
    markets: vec![],
})])?;

while let Some(event) = handle.next().await {
    println!("{event:?}");
}
handle.close();

Pass specific market condition IDs in markets to filter events to those markets, or leave the Vec empty to receive events for all your open activity.

Subscription types reference

The SubscriptionSpec enum covers every channel the Polymarket WebSocket server exposes:

SubscriptionSpec variant	Channel	Data streamed
Market(MarketSubscription)	Market	Order book snapshots and deltas, mid-price updates, last trade price and size.
User(UserSubscription)	User	Your order placements, fills, partial fills, and cancellations. Requires SecureClient.
Sports(...)	Sports	Live scores and game-state updates for sports prediction markets.
Comments(...)	RTDS Comments	Real-time discussion comments attached to markets.
CryptoPricesBinance(...)	RTDS Crypto	Crypto price feed sourced from Binance.
CryptoPricesChainlink(...)	RTDS Crypto	Crypto price feed sourced from Chainlink.

You can combine multiple SubscriptionSpec values in a single subscribe() call to multiplex several channels over one connection:

let mut handle = client.subscribe(vec![
    SubscriptionSpec::Market(MarketSubscription {
        token_ids: vec!["TOKEN_ID_A".into(), "TOKEN_ID_B".into()],
        custom_feature_enabled: false,
    }),
    SubscriptionSpec::Sports(sports_sub),
])?;

Closing the stream

Always call handle.close() when you are finished consuming events. This sends a clean close frame to the server and releases the underlying TCP connection:

handle.close();

Dropping the handle without calling close() will eventually time out on the server side, but calling close() explicitly is faster and avoids leaving stale connections open on the Polymarket WebSocket server.