Common messages · WebSocket

See connection, authentication and subscription limits in the WebSocket overview.

Unsubscribe

Subscription accepted (type: subscribed)

RECEIVEsubscribed

Server → client

Acknowledges the accepted subscription ID. A missing or blank request ID becomes default.

Message fields

Field	Type	Required	Description
type	string	Yes	Allowed: "subscribed"
subscription_id	string	Yes	The accepted request id, or default if the request id was omitted or blank.

Examples

{
  "type": "subscribed",
  "subscription_id": "btc-jpy"
}

Application heartbeat (type: ping)

SENDping

Client → server

The application heartbeat echoes ts in a pong message. It is separate from WebSocket protocol ping/pong frames. The server sends protocol pings every 30 seconds and requires a protocol pong within the 90-second read deadline; browsers handle those frames automatically.

Reply: pong

Message fields

Field	Type	Required	Description
type	string	Yes	Always ping. Allowed: "ping"
ts	string	No	Opaque value echoed in the pong; defaults to an empty string. Default: ""

Examples

{
  "type": "ping",
  "ts": "1787974923000"
}

Heartbeat reply (type: pong)

RECEIVEpong

Server → client

Echoes the application ping value in ts; it is not a WebSocket protocol pong frame.

Message fields

Field	Type	Required	Description
type	string	Yes	Allowed: "pong"
ts	string	Yes

Examples

{
  "type": "pong",
  "ts": "1787974923000"
}

Errors (type: error)

RECEIVEerror

Server → client

Subscription validation errors preserve the existing subscriptions and keep the connection open. subscribe_failed is followed by disconnection. Malformed JSON or messages exceeding 64 KiB may close the connection without a JSON error.

code	Meaning
invalid_subscription	Invalid quote, channel, symbol, or interval.
subscription_limit	More than 100 subscriptions on this connection.
symbol_limit	Symbol quota exceeded, or conflicting all-asset subscription.
unknown_message	Unsupported message type.
subscribe_failed	Realtime event service unavailable; reconnect with backoff.

Message fields

Field	Type	Required	Description
type	string	Yes	Always error. Allowed: "error"
code	string	Yes	Machine-readable error code; see the error codes above. Allowed: "invalid_subscription", "subscription_limit", "symbol_limit", "unknown_message", "subscribe_failed"
message	string	Yes	Human-readable details.

Examples

{
  "type": "error",
  "code": "symbol_limit",
  "message": "a quote-only market subscription uses the full symbol budget; use a separate connection"
}