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Beta access required. The Retail Combos API is available only to explicitly enabled Retail API users.
A combo is a user-defined instrument containing 2–10 legs. Each leg identifies an existing market symbol and whether the combo buys or sells that leg. Once open, a combo trades through the normal Orders API; an RFQ is optional and provides a price-discovery and paired order-submission workflow over the same order book. All calls use normal Retail API authentication at:

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Endpoints

On the Retail API, Combo and RFQ creation share an additional edge rate limit of 10 requests per 10 seconds, enforced per API key and per IP. Separately, combo creation has a participant-wide service quota of 1,000 new instruments per week across all accounts and both Retail and Institutional APIs. The quota resets Monday at 00:00 UTC; returning an existing canonical combo does not consume it.

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Create a Combo

POST /v1/combos accepts 2–10 unique legs:
Leg symbols must be open, tradable, supported instruments. Duplicate symbols and invalid combinations are rejected. A canonical set of legs always maps to the same caoc-... combo symbol, so creating an existing combo returns that instrument.

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Get a Combo

GET /v1/combos?symbol=caoc-... requires the exact combo symbol. The response contains a combos array; an unknown symbol returns an empty array. This endpoint does not paginate.

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See Also

RFQ API

Create and manage combo RFQs and quotes

Authentication

Sign Retail API requests

Private WebSocket

Receive RFQ and quote lifecycle events