Quote USDC → stock token (one leg per chain the ticker lists, better first)

POST 
/quote/buy

Requires ownership_proof for each wallet provided. Returns one best leg per chain the ticker lists (up to five today: sol, eth, robinhood, base, arbitrum): the signable quote legs (one per chain). Cache the returned quote_id; every signed leg is submitted together at /trade/submit. Set quote_only: true for a non-executable price preview (the wallet need not be funded; quote_id, expires_at, and signable_payloads are omitted).

502 provider_unavailable also fires when a priority:"speed" cross-chain leg's sol-origin deposit fails to compile (an RPC blockhash read failure): the whole quote is refused, not just that cell; retry.

Request

Responses

200

OK

400

Invalid request body, slippage out of range, unknown ticker, zero amount, or (pinned execution: "user_operation") a wallet not delegated to Modular Account v2.

401

Ownership-proof failure.

403

A wallet on the request was flagged by sanctions screening. Permanent; do not retry with the same wallet.

410

Quote stale (upstream price moved past expiry mid-build).

422

No fillable routes returned by the planner, or a basket listing whose issuer-published price is unusable.

429

Sliding window exceeded: per-IP or per-(IP, wallet), plus a per-organisation bucket (shared across all of your keys) whenever a valid X-API-Key is presented. Retry-After header carries delta-seconds.

502

Upstream provider failed or rate-limited us.

503

screening_unavailable: sanctions screening could not be completed and the request was rejected (fail-closed). Transient; back off and retry. integrator_fee_misconfigured (with an X-API-Key): your configured fee schedule no longer fits a venue Treasures routes through. A Treasures-side configuration issue that retrying soon won't clear; contact Treasures, or send integrator_fee_bps: 0 to quote without your fee.