> ## Documentation Index > Fetch the complete documentation index at: https://docs.agg.market/llms.txt > Use this file to discover all available pages before exploring further. # Place an order directly > Places a market order on a single named venue without a prior quote. The route is priced and funded server-side and always produces exactly one order. `externalId` is required and unique within your app — two different users of the same app cannot share one — so retrying a timed-out request with the same value returns 409 instead of trading twice. ## OpenAPI ````yaml /openapi/openapi.json post /execution/orders openapi: 3.0.2 info: title: AGG API version: 1.0.0 description: >- Prediction market aggregator REST API — authentication, users, venue events, venue markets, orderbooks, charts, and execution workflows. servers: - url: https://api.agg.market description: Production - url: https://api.staging.agg.market description: Staging security: [] paths: /execution/orders: post: tags: - Execution summary: Place an order directly description: >- Places a market order on a single named venue without a prior quote. The route is priced and funded server-side and always produces exactly one order. `externalId` is required and unique within your app — two different users of the same app cannot share one — so retrying a timed-out request with the same value returns 409 instead of trading twice. operationId: placeOrder requestBody: required: true content: application/json: schema: additionalProperties: false type: object required: - venue - venueMarketOutcomeId - side - externalId properties: venue: description: >- The venue to trade on. Singular by design — this endpoint never splits an order. type: string enum: - kalshi - polymarket - limitless - opinion - predict - probable - myriad - hyperliquid - novig venueMarketOutcomeId: minLength: 1 description: >- The outcome to trade. May be the outcome on another venue: it is resolved through matched-outcome links to the equivalent outcome on `venue`. Passing the id that already lives on `venue` is the unambiguous form. type: string side: description: >- Trade direction. `sell` closes an existing position on `venue`. type: string enum: - buy - sell maxSpend: exclusiveMinimum: true description: Buy only. Maximum all-in USD spend, inclusive of app fee. type: number minimum: 0 sellShares: exclusiveMinimum: true description: Sell only. Number of contracts to sell. type: number minimum: 0 externalId: minLength: 1 maxLength: 36 description: >- Idempotency key. Your own id for this trade — required, and unique within your app: two different users of the same app cannot share one. A repeat is rejected with 409 rather than trading twice, so it is safe to retry a request that timed out using the same value. type: string slipCapBps: minimum: 0 description: >- Slippage cap in basis points. Defaults to 500 (5%) when omitted. On sells set this explicitly: `sellShares` bounds the shares sold, not the proceeds. type: number responses: '200': description: '200' content: application/json: schema: type: object required: - orderId - externalId - venue - status - quoteId - quotedPriceRaw - quotedCostRaw - quotedSharesRaw properties: orderId: description: The single order this call created. type: string externalId: description: >- Echoed back so a webhook or socket event can be tied to this response. type: string venue: description: The venue the order was placed on. type: string enum: - kalshi - polymarket - limitless - opinion - predict - probable - myriad - hyperliquid - novig status: description: >- Always `pending`: the order is accepted and queued for execution, not yet filled. Poll `GET /execution/orders` or listen for order events for the terminal state. type: string enum: - pending quoteId: description: >- Server-minted quote backing this order. Useful for support, not required. type: string quotedPriceRaw: description: >- Quoted price, decimal string (e.g. "0.53"). `null` if the order row does not carry a quoted price — the order is still live; re-fetch it from `GET /execution/orders` rather than treating this as zero. type: string nullable: true quotedCostRaw: description: >- Quoted cost, 6-decimal atomic USDC. `null` under the same conditions as `quotedPriceRaw`. type: string nullable: true quotedSharesRaw: description: >- Quoted shares, 6-decimal atomic. `null` under the same conditions as `quotedPriceRaw`. type: string nullable: true '400': description: '400' content: application/json: schema: type: object required: - message properties: message: type: string code: type: string enum: - quote_not_found - quote_expired - quote_already_executed - quote_cancelled - quote_user_mismatch - quote_app_blocked - quote_unfillable - quote_min_order_size - quote_stale_status - quote_stale_price - quote_insufficient_balance - quote_market_inactive - venue_not_executable - outcome_ambiguous '401': description: '401' content: application/json: schema: type: object required: - message properties: message: type: string '403': description: '403' content: application/json: schema: type: object required: - message properties: message: type: string '404': description: '404' content: application/json: schema: type: object required: - message properties: message: type: string '409': description: '409' content: application/json: schema: type: object required: - message properties: message: type: string security: - appId: [] bearerAuth: [] components: securitySchemes: appId: type: apiKey in: header name: x-app-id description: Your application ID. Required for all app-tier and user-tier routes. bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- JWT access token returned by POST /auth/verify. Required for user-tier routes. ````