RPC Commands

The Cadenza WebSocket API uses RPC (Remote Procedure Call) for request/response operations over the Centrifugo protocol.

Communication Style

RPC provides synchronous request/response communication over WebSocket:

┌──────────┐                    ┌──────────────┐                    ┌──────────┐
│  Client  │                    │  Centrifugo  │                    │  Cadenza │
└────┬─────┘                    └──────┬───────┘                    └────┬─────┘
     │                                 │                                 │
     │  RPC Request (method, params)   │                                 │
     │────────────────────────────────▶│                                 │
     │                                 │  Forward to handler             │
     │                                 │────────────────────────────────▶│
     │                                 │                                 │
     │                                 │  Response (result/error)        │
     │                                 │◀────────────────────────────────│
     │  RPC Response                   │                                 │
     │◀────────────────────────────────│                                 │

Method Naming Convention

RPC methods follow the pattern: {category}.{resource}.{action}

Category	Purpose	Description
command.*	Write operations	Create, update, delete, mutate state
query.*	Read operations	List, get, fetch data

Examples:

• command.trade_order.submit - Submit a new order (write)
• query.instrument.list - List instruments (read)
• command.trading_account.connect - Connect account (write)
• query.orderbook.get - Get order book (read)

Making RPC Calls

# Pattern for RPC calls
result = await client.rpc(method, params)

# Using SDK models
params = RpcListInstrumentsParams(venue=Venue.BINANCE, limit=50)
result = await client.rpc("query.instrument.list", params.to_dict())
parsed = RpcListInstrumentsResult.from_dict(result.data)

Response Format

All RPC responses follow a consistent structure:

Success Response:

Field	Type	Description
data	object/array	Response payload

Error Response:

Field	Type	Description
error	object	Error details
error.code	integer	Error code
error.message	string	Error description

Error Handling

When an RPC call fails, the response contains an error object with a code and message. Error codes follow the format 22XXX where 22 indicates a business logic error.

Common error codes:

Code	Message	Description
22015	Invalid argument	Invalid argument for operation
22016	Not found	Requested resource not found
22017	Already exist	Resource already exists
22018	Permission denied	Insufficient permissions
22023	Unauthorized	Not authorized for this operation

For the complete list of error codes and handling patterns, see Error Handling.

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RPC Commands Reference

System

Method	Description	Details
query.system.info	Get API information	View
query.system.check	Health check	View

Venues

Method	Description	Details
query.venue.list	List supported venues	View

Instruments

Method	Description	Details
query.instrument.list	List instruments	View
command.instrument.sync	Sync from exchange	View
command.instrument.enable	Enable instrument	View
command.instrument.disable	Disable instrument	View

Order Books

Method	Description	Details
query.orderbook.get	Get order book	View
query.orderbook.list	List order books	View

Trading Accounts

Method	Description	Details
query.trading_account.list	List accounts	View
command.trading_account.connect	Connect account	View
command.trading_account.disconnect	Disconnect account	View
command.trading_account.enable	Enable account	View
command.trading_account.disable	Disable account	View

Credentials

Method	Description	Details
query.credential.list	List credentials	View
command.credential.create	Create credential	View
command.credential.verify	Verify credential	View
command.credential.revoke	Revoke credential	View

Trade Orders

Method	Description	Details
query.trade_order.list	List orders	View
query.trade_order.get	Get order	View
command.trade_order.submit	Submit order	View
command.trade_order.cancel	Cancel order	View

Portfolios

Method	Description	Details
query.portfolio.list	List portfolios	View
query.portfolio.get	Get portfolio	View

Subscriptions

Method	Description	Details
query.subscription.list	List subscriptions	View
command.subscription.create	Create subscription	View