Place Order Dispatcher

POST

orders

curl --request POST \
  --url https://api.polysimulator.com/v1/orders \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "market_id": "0xabc123...",
  "side": "BUY",
  "outcome": "Yes",
  "quantity": "10",
  "order_type": "market",
  "price": "0.68"
}
'

{
  "order_id": 123,
  "status": "<string>",
  "order_type": "<string>",
  "side": "<string>",
  "outcome": "<string>",
  "price": "<string>",
  "quantity": "<string>",
  "notional": "<string>",
  "fee": "<string>",
  "filled_at": "<string>",
  "cancelled_reason": "<string>",
  "price_source": "<string>",
  "fill_source": "<string>",
  "slippage_bps": 123,
  "quote_age_ms": 123,
  "spread_bps": 123,
  "impact_bps": 123,
  "book_walk_levels": 123,
  "account_balance": "<string>",
  "position": {},
  "client_order_id": "<string>",
  "magic": 123,
  "magic_label": "<string>",
  "error": "<string>",
  "error_message": "<string>",
  "amount_interpreted_as": "<string>",
  "is_replay": true,
  "warnings": [
    "<string>"
  ]
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

Authorizations

X-API-Key

string

header

required

Issue from /v1/keys (or admin-issued for enterprise tier).

Headers

Idempotency-Key

string | null

X-API-Key

string | null

Your PolySimulator API key

POLY_API_KEY

string | null

Polymarket-CLOB-compat alias for X-API-Key (underscore form). SDK clients ported from Polymarket can authenticate without changing header names. X-API-Key takes precedence when both are provided.

Poly-API-Key

string | null

PM-CLOB-compat dashed-form alias for X-API-Key. Same value semantics as POLY_API_KEY but with HTTP-conventional dash separators. Both spellings are accepted end-to-end.

authorization

string | null

PM-CLOB-compat: Authorization: Bearer ps_live_... (or ps_test_...) is accepted as an alias for X-API-Key so py-clob-client and other ported SDKs authenticate without header name changes. Bearer JWTs are NOT accepted here — use the dashboard-auth endpoints for those.

Body

application/json

PlaceOrderRequest · object
PmSendOrderRequest · object[]

market_id

string

required

Polymarket condition_id

Maximum string length: 256

side

enum<string>

required

Available options:

BUY,

SELL

outcome

string

required

Outcome label, e.g., Yes or No

Maximum string length: 200

quantity

string | null

Number of shares as decimal string, e.g. '10.5'. Required UNLESS amount is provided (BUY market orders only — Polymarket convention).

amount

string | null

USD amount to spend, as decimal string (e.g. '10.50'). Polymarket convention for BUY market orders: amount=5 means 'spend $5' (versus our quantity=5 which means 'buy 5 shares ≈ $5 × current_price'). Only valid when side=BUY and order_type=market; the handler derives quantity = floor4(amount / price) using the caller-supplied worst-price limit in the price field (NOT the eventual fill price). This is conservative: the trade can't spend more than amount USD even at the worst acceptable price; a better fill means more shares. The result is rounded down to 4 decimal places (the matching engine's share quantum) and capped at the per-trade share limit. For SELL or limit orders, use quantity (shares). Mutually exclusive with quantity — supplying both is a 400 error.

order_type

enum<string>

default:market

Order type

Available options:

market,

limit

price

string | null

For limit orders: the limit price (0.01-0.99, required). For market orders: the worst acceptable price — Polymarket-style slippage protection (required). BUY won't fill above this price; SELL won't fill below it. All market orders are effectively marketable limit orders, matching Polymarket's execution model.

time_in_force

enum<string>

default:GTC

GTC = Good-Til-Cancel (default for limit orders, persists until filled/cancelled; on a market order it is replaced by IOC), FOK = Fill-Or-Kill (all-or-nothing: fills only if displayed depth within the limit covers the full size), FAK = Fill-And-Kill (Polymarket term for partial fill, cancel remainder — equivalent to IOC), IOC = Immediate-Or-Cancel (partial fill, cancel remainder; the default for market orders), GTD = Good-Til-Date (limit orders only; resting limit auto-expiring at expiration; live on production, gated by the ORDER_SEMANTICS_PM_V2_ENABLED rollout flag — where that flag is off, GTD is rejected as an invalid value)

Available options:

GTC,

FOK,

FAK,

IOC,

GTD

client_order_id

string | null

Idempotency key

Maximum string length: 256

expiration

string | null

Unix-seconds expiration timestamp — required for time_in_force=GTD (PM convention: the order auto-cancels once the timestamp passes), ignored for every other TIF. Rolling out behind ORDER_SEMANTICS_PM_V2_ENABLED.

post_only

boolean | null

default:false

Polymarket's postOnly: the order must REST on the book — if it would cross the spread (marketable at placement) it is rejected with 400 INVALID_POST_ONLY_ORDER instead of executing, guaranteeing maker-side execution. Only valid for limit orders with GTC/GTD time-in-force (FOK/FAK/IOC/market combinations are rejected with INVALID_POST_ONLY_ORDER_TYPE, matching PM). Rolling out behind ORDER_SEMANTICS_PM_V2_ENABLED; advisory (ignored) until the flag is on.

wallet_id

integer | null

Multi-wallet (May 8 launch). When set to a SANDBOX wallet the user owns, the trade debits/credits Wallet.balance directly and the resulting Order is tagged with trade_source='ui_sandbox' (excluded from the public leaderboard). When set to a MAIN/API wallet the user owns, the cash flow is routed to that explicit wallet (otherwise we default to API for /v1/orders). Omit for legacy back-compat behaviour: cash flows to the user's API wallet.

magic

integer | null

Bot / strategy identifier (MetaTrader 5 style magic number), 0..9223372036854775807. Not unique: every order a bot places can share it, so the bot can later filter GET /v1/orders, export trades and cancel-all with ?magic= without touching other bots on the same account. Omitted: the API key's default_magic applies, if configured.

Required range: 0 <= x <= 9223372036854776000

magic_label

string | null

Optional human-readable bot name shown next to the magic number (max 32 printable characters, trimmed; blank means none), e.g. 'arb-v1'. Omitted: the API key's default_magic_label applies, if configured.

Maximum string length: 32

Response

Object body → OrderResponse (PolySim single-order) OR OrderAck when the user routes through Order Pipeline V2 (per-user allowlist or global flag — ack-then-reconcile, no fill data in the body; clients poll GET /v1/orders/{order_id} for the post-reconcile fill fields). Array body → List[PmSendOrderResponse] (PM batch, max 15). The OrderAck schema is registered under /v1/orders/{order_id} (DELETE)'s 202 response.

OrderResponse · object
OrderAck · object
PmSendOrderResponse · object[]

order_id

integer

required

status

string

required

order_type

string

required

side

string

required

outcome

string

required

price

string

required

quantity

string

required

notional

string

required

fee

string

required

filled_at

string | null

cancelled_reason

string | null

Why a CANCELLED order was cancelled - a stable snake_case machine tag. An order cancelled inside the request that created it (a marketable IOC/FAK that could not fill) reports the no-fill cause, for example 'price_did_not_cross', 'fok_insufficient_depth', 'book_depleted', 'depth_required', 'no_live_price' or 'no_book_price'. An order cancelled while resting on the book reports for example 'gtd_expired', 'stale_market', 'stale_or_mismatched_book' or 'reset'. Null on non-cancelled statuses and on legacy rows, so branch on status to detect cancellation and on this field to learn the cause.

price_source

string | null

fill_source

string | null

slippage_bps

integer | null

quote_age_ms

integer | null

spread_bps

integer | null

impact_bps

integer | null

book_walk_levels

integer | null

account_balance

string | null

position

Position · object | null

client_order_id

string | null

magic

integer | null

magic_label

string | null

error

string | null

error_message

string | null

amount_interpreted_as

string | null

is_replay

boolean | null

warnings

string[] | null

curl --request POST \
  --url https://api.polysimulator.com/v1/orders \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "market_id": "0xabc123...",
  "side": "BUY",
  "outcome": "Yes",
  "quantity": "10",
  "order_type": "market",
  "price": "0.68"
}
'

{
  "order_id": 123,
  "status": "<string>",
  "order_type": "<string>",
  "side": "<string>",
  "outcome": "<string>",
  "price": "<string>",
  "quantity": "<string>",
  "notional": "<string>",
  "fee": "<string>",
  "filled_at": "<string>",
  "cancelled_reason": "<string>",
  "price_source": "<string>",
  "fill_source": "<string>",
  "slippage_bps": 123,
  "quote_age_ms": 123,
  "spread_bps": 123,
  "impact_bps": 123,
  "book_walk_levels": 123,
  "account_balance": "<string>",
  "position": {},
  "client_order_id": "<string>",
  "magic": 123,
  "magic_label": "<string>",
  "error": "<string>",
  "error_message": "<string>",
  "amount_interpreted_as": "<string>",
  "is_replay": true,
  "warnings": [
    "<string>"
  ]
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

{
  "error": "<string>",
  "message": "<string>",
  "details": {},
  "request_id": "<string>"
}

Overview

Endpoints

Authorizations

Headers

Body

Response