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 →
Guides
Every page in this section, and who each one is for.
Seven pages, each answering one question end to end. They are written to be read in two passes: the opening section is plain English about what the thing is and what it costs you, and the rest is the contract — exact endpoints, exact field names, exact error behaviour.
Where a capability is a target rather than something that runs today, the page says so in the same sentence as the capability, and every page that has limits worth knowing carries them in one Current limits block rather than scattered through the prose.
Quickstart
Provision your own tenant, exchange the login for a token, and make a call that comes back with rows in it. About ten minutes.
Authentication
Portal logins, self-serve machine keys, the OAuth exchange, HMAC request signing — and which pillar accepts which.
API conventions
Money and quantities as strings, typed security identifiers, sortable ids, four pagination shapes and three error shapes.
The sandbox
What is real, what is simulated, how the trial behaves, and the limits — published rather than discovered.
Events & streaming
CloudEvents over Server-Sent Events, socket frames over WebSocket, Kafka by arrangement, Kafka by arrangement, and how to choose between them.
SDKs & tools
A Python client and scoped TypeScript clients for BaaS and Portfolio Management — what each covers, how to install them, and when curl is the shorter path.
Data migration
Moving an existing book — accounts, cost basis, transaction history — onto Interpose, and what the import will not do for you.
Looking something up instead
The endpoint reference is not a guide — it is the shortlist of routes a wealth or investing integration reaches for first, each one confirmed against the running services, with the paging and async behaviour that is easy to get wrong stated per endpoint.
Getting help
Email support@interposehq.com. If you find something in these pages that disagrees with the running system, tell us; that is a defect in the page, not in your reading of it.