AsyncAPI channel · Alpaca · Alpaca WebSocket Streaming APIs

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The single root WebSocket path used by every market data stream (stocks, crypto, news, and the test feed). All control messages (auth, subscribe, unsubscribe) and all data messages flow over this path. The set of allowed subscription topics depends on the server selected.

Open source AsyncAPI → All Alpaca channels Alpaca provider profile
Provider: Alpaca AsyncAPI: v2.6.0 Spec: Alpaca WebSocket Streaming APIs Operations: 2 Messages: 22

Channel address

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Operations

publish
marketDataClientSend
Messages the client sends to a market data stream.
marketDataServerReceive
Messages the server pushes on a market data stream.

Messages

AuthRequest
Sent by the client immediately after the connection is opened. The client has 10 seconds to authenticate or it is disconnected.
Content-Type:
SubscribeRequest
Subscribes the connection to one or more channels for the listed symbols. Use "*" to subscribe to every symbol on a channel (where the plan allows).
Content-Type:
UnsubscribeRequest
Unsubscribe from channels
Content-Type:
ControlSuccess
Server confirms a control event. Common values for msg are "connected" (right after the socket opens) and "authenticated" (after a successful auth handshake).
Content-Type:
ControlError
Server reports an error. Known codes include 400 (invalid syntax), 401 (not authenticated), 402 (auth failed), 403 (already authenticated), 404 (auth timeout), 405 (symbol limit exceeded), 406 (connec
Content-Type:
SubscriptionState
Server echoes the full set of channels and symbols the connection is currently subscribed to after every subscribe or unsubscribe message.
Content-Type:
StockTrade
Stock trade (t)
Content-Type:
StockQuote
Stock quote (q)
Content-Type:
StockBar
Stock minute bar (b)
Content-Type:
StockUpdatedBar
Bar restated after late trades arrived.
Content-Type:
StockDailyBar
Stock daily bar (d)
Content-Type:
TradingStatus
Trading status (s)
Content-Type:
Luld
Limit Up / Limit Down price band update.
Content-Type:
TradeCorrection
Trade correction (c)
Content-Type:
TradeCancelError
Trade cancel / error (x)
Content-Type:
CryptoTrade
Crypto trade (t)
Content-Type:
CryptoQuote
Crypto quote (q)
Content-Type:
CryptoBar
Crypto minute bar (b)
Content-Type:
CryptoUpdatedBar
Crypto updated bar (u)
Content-Type:
CryptoDailyBar
Crypto daily bar (d)
Content-Type:
CryptoOrderbook
Crypto orderbook (o)
Content-Type:
NewsItem
News article (n)
Content-Type:

About AsyncAPI

The AsyncAPI specification describes event-driven APIs the way OpenAPI describes request/response APIs. A channel is the named pipe — a webhook URL, a Kafka topic, a WebSocket route, an MQTT subject — that producers and consumers publish or subscribe to. Each channel carries one or more messages with structured payloads, and an operation declares whether a given party sends or receives on that channel.

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