Wire Contracts (Protobuf)

contracts/proto/order_execution.proto is the current versioned contract between the Kotlin platform runtime and the Go matching engine.

Command Metadata (Shared)

Every command carries a CommandMetadata: command_id, correlation_id, actor_id, actor_type, occurred_at, trace_id, causation_id, run_id, venue_session_id, client_order_id, bot_id, bot_version.

Commands

Message	Fields
`SubmitOrder`	`metadata`, `order_id`, `instrument_id`, `participant_id`, `account_id`, `side`, `order_type`, `quantity`, `limit_price`, `time_in_force`
`CancelOrder`	`metadata`, `order_id`, `reason`
`ModifyOrder`	`metadata`, `order_id`, `quantity`, `limit_price`

OrderQuantity is { units: string }; Price is { nanos: string, currency: string }.

Result & Events

Message	Fields
`SubmitOrderResult`	`oneof outcome { accepted: OrderAccepted, rejected: OrderRejected }`, `executions: ExecutionCreated[]`, `trades: TradeCreated[]`
`OrderAccepted`	`event_id`, `order_id`, `engine_order_id`, `occurred_at`
`OrderRejected`	`event_id`, `order_id`, `code`, `reason`, `occurred_at`
`ExecutionCreated`	`event_id`, `execution_id`, `order_id`, `instrument_id`, `quantity`, `execution_price`, `occurred_at`
`TradeCreated`	`event_id`, `trade_id`, `execution_id`, `buy_order_id`, `sell_order_id`, `instrument_id`, `quantity`, `price`, `occurred_at`

Service

service OrderExecutionService {
  rpc SubmitOrder(SubmitOrder) returns (SubmitOrderResult);
  rpc SubmitOrders(stream SubmitOrder) returns (stream SubmitOrderResult);
  rpc CancelOrder(CancelOrder) returns (SubmitOrderResult);
  rpc ModifyOrder(ModifyOrder) returns (SubmitOrderResult);
  rpc HealthCheck(HealthCheckRequest) returns (HealthCheckResponse);
}

Enums

OrderSide: ORDER_SIDE_UNSPECIFIED, ORDER_SIDE_BUY, ORDER_SIDE_SELL
OrderType: ORDER_TYPE_UNSPECIFIED, ORDER_TYPE_LIMIT (market orders not yet defined at this layer)
TimeInForce: TIME_IN_FORCE_UNSPECIFIED, TIME_IN_FORCE_DAY, TIME_IN_FORCE_IOC

Contracts are versioned and additive-first; make check-proto-additive verifies compatibility in CI.

Learn More

contracts/proto/order_execution.proto — the full, current source of truth
contracts/proto/README.md — contract conventions
Orders API — the public JSON shape this maps to/from
Runtime Schema — how these messages materialize into Postgres