Polymarket US

Step zero — from nothing to your first trade

Polymarket US uses a venue-custodied account and is separate from wallet-based Polymarket on Polygon. No wallet or chain transaction is part of this lane.

Create the account. Sign up at polymarket.us. Identity verification is mandatory before API trading; expect government-ID KYC.
Create credentials. In your venue account’s API settings, create the UUID key ID and base64 Ed25519 API secret. This secret authenticates requests; it is not a Solana wallet key. Send it only for an authenticated call. Predictefy uses it transiently and never persists it.
Fund it. Deposit venue-custodied USD through Polymarket US’s regulated in-venue bank or card rails. No crypto collateral or bridge route applies. Start with enough to meet the selected market’s published minimumTradeQty plus fees; there is no repo-grounded global minimum.
Allow time. Setup is about 10 minutes after approval; KYC may take a day.
Check access. Eligibility, geography, KYC, and other compliance duties remain yours; confirm access before funding.

What you need first

Production status: Armed for build, submit, and cancel as verified on 2026-08-15.
Wallet and chain: No order-body wallet signature or chain transaction. The Ed25519 secret is request-auth material and is not a Solana wallet key.
Venue account: Yes. Use an identity-verified, funded Polymarket US account.
Credentials: A caller UUID key ID and base64 Ed25519 API secret. Keep both in your process and send them only for the authenticated call; Predictefy never persists them or generated headers.
Funding: Fund the venue-custodied account through regulated in-venue rails. The funding registry pins no crypto collateral or bridge route.

Polymarket US is source-ready but default-off. GET /v1/exec/venues will omit it unless an owner explicitly sets POLYMARKET_US_EXECUTION_ENABLED=true; this implementation did not enable any environment. Build resolves the native slug and <slug>:long|short outcome from Predictefy’s catalog and returns a buildVersion: 1 authless request.

Field	Type	Required	Meaning
`marketId`	string	yes	Exact catalog-native market slug
`outcomeId`	`<marketId>:long` or `:short`	yes	Exact catalog-native outcome id
`side`	`"buy"` or `"sell"`	yes	Combined with the outcome to select the venue intent
`type`	`"limit"`	yes	Market/cash-sized orders are not supported
`amount`	number > 0	yes	Contract quantity aligned to catalog `minimumTradeQty`; `cashOrderQty` is never sent
`price`	number from 0.01 through 0.99	yes	User/outcome price rounded to the catalog market’s `orderPriceMinTickSize`

The venue publishes both increments per market. Predictefy persists them during catalog ingest, includes the exact values in the authless artifact, and fails build closed if either rule is absent or unsupported. It does not assume every market uses the fixture’s 0.001 price tick or quantity 1.

Submit accepts only executionId, canonical UUID keyId, and secretKey. The lane checks version, bounds, complete body shape, stored intent, and notional before credential access, then creates X-PM-Access-Key, X-PM-Timestamp, and X-PM-Signature over ${timestamp}${METHOD}${pathname}. The venue does not include the body in this signature, so a captured header set is replayable with a different body during the venue timestamp window. The relay is TLS-only, rejects redirects, and never logs headers or bodies; operators must preserve that rule in proxy and APM configuration. Credentials and auth headers are never persisted.

Identity verification is required before API trading. Polymarket US documents a 20 requests/second limit per API key, so callers retain their own quota instead of sharing a service key. Eligibility, geography, and legal/compliance duties remain with the caller and operator. The separate ISV/IB institutional-partner path is out of scope. The repo guide docs/polymarket-us-execution.md carries the official source list and full security boundary.