Sandbox environment. Interpose is not a registered broker-dealer and holds no FINRA approval. Every API documented here is available in a simulated evaluation environment only — no client assets are held, no real trades are executed, and no custody is provided. The calculation engines are the production code paths; fills, custody, settlement and KYC decisioning are simulated. What is real and what is simulated →
API Reference
Brokerage-as-a-Service
The brokerage operations an API key can reach — users and accounts, orders, positions and tax lots, transactions, funding, market data, webhooks and more. The reference is generated from the service code, using the same scope rules that decide what a key can reach, so an operation open only to a signed-in portal user is not in it. Base URL https://interposehq.com/api/baas; every path below starts with /v1.
A generated reference is the wrong place to learn the handful of things that are easier to get wrong than to look up. Read API conventions for how money, quantities and pagination are typed, authentication for how a key is scoped to your firm, and events & streaming before you build on the stream.