Reference

The Streaming API allows you to subscribe to the events related to the corresponding entities via the WebSocket interface. As we prioritize even delivery over redundancy, in some rare cases, the same event may arrive twice. Make sure to track the unique source of the event, like deploy hash and event id, where needed.

The update events are emitted only when the direct entity properties are changed. Changes in the optional fields will not trigger a WebSocket message.

Streaming API connection may close when a new version of the API is deployed; thus, make sure to include the reconnection logic in your code.

Format

The messages are sent as JSON objects with the following properties:

Property	Type	Description
action	string	Action name
data	Entity	Affected entity
timestamp	datetime	Timestamp of the network object, deploy or block, that triggered the action
extra	mixed	Extra data provided with the message. This property is optional.

Persistent sessions (beta)

Applications may experience failures on their end, resulting in closing the WebSocket connections. To ensure no messages are lost during the downtime, it's possible to declare the WebSocket connection as "persistent" by adding a Persistent-Session header. Reconnecting with the same Persistent-Session header value would connect the application to the same queue containing the messages received during the downtime.

Persistent Streaming API sessions not available for the "Free" tier

Streams

Below is a full list of the available CSPR.cloud Streaming API streams:

Stream	Actions	Description
Account balance	updated	Notifies about newly created or updated Accounts
Block	created	Notifies about newly created Blocks
Contract	created	Notifies about newly created Contracts
Contract package	created, updated	Notifies about newly created or updated Contract packages
Contract-level events	emitted	Notifies about newly emitted contract-level events
Deploy	created	Notifies about newly created Deploys
Fungible token action	created	Notifies about newly created Fungible token actions
Non-fungible token (NFT)	created, updated	Notifies about newly created or updated NFTs
Non-fungible token (NFT) action	created	Notifies about newly created NFT actions
Transfer	created	Notifies about newly created Transfers

Prerequisites

To follow Streaming API examples you'll need to install the wscat NPM utility:

npm install -g wscat