Trading API

Overview

Trading API is an application interface for submitting, changing, canceling, and querying orders or trades and for receiving market, execution, position, or account information. It is broader than a price-data API because it can create financial commitments and must represent order lifecycle, execution, and risk controls precisely. The Trading API owner should publish stable error semantics and guidance on whether correction, retry, status lookup, or escalation is appropriate.

Key risks include duplicate orders, stale prices, incorrect side or quantity, missed fills, out-of-order events, rate-limit failure, market impact, credential compromise, and positions diverging from internal records.

A production implementation should authenticate and authorize strongly, validate symbols and quantities, use idempotent client order IDs, handle partial fills, sequence events, enforce limits, reconcile executions, and provide kill or cancellation controls. The Trading API contract should define identifiers, validation, authorization, status semantics, errors, limits, and version behavior at the same boundary.

Useful measures include order acceptance and rejection, execution latency, fill rate, cancel success, duplicate prevention, event-sequence gaps, and position-reconciliation breaks. Trading API is closely connected to Limit Order, Smart Order Routing, and Position Reconciliation. Testing Trading API should cover malformed input, denied access, rate limits, timeouts, duplicates, asynchronous completion, and version changes.

Observability for Trading API should record operation, version, principal, request ID, latency, retry count, error code, and final state without exposing secrets.

Data handled by Trading API should use documented types, units, timestamp rules, nullable fields, and enum behavior to prevent silent interpretation errors. For Trading API, the application should preserve a correlation path from request construction through response, asynchronous completion, and final business state.