> ## Documentation Index > Fetch the complete documentation index at: https://docs.swaps.xyz/llms.txt > Use this file to discover all available pages before exploring further. # Place Order > Places a market order (BUY or SELL) directly against the Polymarket CLOB on behalf of the user, using their pre-funded proxy wallet. This endpoint always requires an EIP-712 `signatureByEvmEoa` produced by the user's EOA — see the [Polymarket Signing Guide](../polymarket-signing). The endpoint submits the order synchronously and returns `{ txId, orderResponse }` so callers can poll workflow status. ## OpenAPI ````yaml /swap-api-reference/openapi.json post /workflows/polymarket/placeOrder openapi: 3.1.0 info: title: Swaps API description: >- The Swaps API provides instant cross-chain swap and bridge functionality for decentralized applications. It supports multiple virtual machines (EVM, Solana, Bitcoin) and various DEX protocols and bridge solutions. version: 3.0.0 contact: name: Swaps.xyz url: https://swaps.xyz servers: - url: https://api-v2.swaps.xyz/api description: Production server security: - ApiKeyAuth: [] paths: /workflows/polymarket/placeOrder: post: tags: - Polymarket summary: Place Order description: >- Places a market order (BUY or SELL) directly against the Polymarket CLOB on behalf of the user, using their pre-funded proxy wallet. This endpoint always requires an EIP-712 `signatureByEvmEoa` produced by the user's EOA — see the [Polymarket Signing Guide](../polymarket-signing). The endpoint submits the order synchronously and returns `{ txId, orderResponse }` so callers can poll workflow status. operationId: placeOrder requestBody: required: true content: application/json: schema: type: object required: - evmEoa - orderRequest - expiration - signatureByEvmEoa properties: evmEoa: $ref: '#/components/schemas/EvmAddress' description: User's EVM wallet address proxyWallet: $ref: '#/components/schemas/EvmAddress' description: Proxy wallet address (optional) orderRequest: type: object required: - side - tokenID - orderType - tickSize - negRisk - amount - slippage properties: side: type: string enum: - BUY - SELL description: Order side tokenID: type: string description: Polymarket CLOB token ID of the outcome to trade orderType: type: string enum: - FOK - FAK description: Order type - Fill-Or-Kill (FOK) or Fill-And-Kill (FAK) tickSize: type: string description: Tick size from the market details (e.g., '0.01') negRisk: type: boolean description: Negative risk flag from the market details amount: type: number description: Order amount in USD (must be a positive number) slippage: type: number description: Slippage tolerance in basis points expiration: type: integer description: >- Unix timestamp (seconds) when `signatureByEvmEoa` expires. Must be in the future and ≤ 300s ahead. signatureByEvmEoa: $ref: '#/components/schemas/Hex' description: >- EIP-712 signature by the EOA over the `PlaceOrder` typed data. See the [Polymarket Signing Guide](../polymarket-signing). example: evmEoa: '0xB9519a08267d7B259eCA6DbD8F7286B1f176A41f' orderRequest: side: BUY tokenID: >- 90234889617199443673709150877675264662915727532354468551650133547723659310093 orderType: FOK tickSize: '0.01' negRisk: true amount: 5 slippage: 100 expiration: 1735689600 signatureByEvmEoa: 0x... responses: '200': description: Order placed successfully content: application/json: schema: type: object properties: txId: type: string description: Box transaction ID for the order workflow orderResponse: type: object properties: success: type: boolean description: Whether the order was accepted errorMsg: type: string description: >- Error message if the order failed (empty string if successful) orderID: type: string description: Unique Polymarket order ID transactionsHashes: type: array items: type: string description: >- Array of on-chain transaction hashes produced by the order status: type: string description: Order status (e.g. 'matched', 'LIVE') takingAmount: type: string description: >- Amount of the counter asset taken in (USDC for BUY, outcome tokens for SELL) makingAmount: type: string description: >- Amount of the offered asset (USDC for BUY, outcome tokens for SELL) example: txId: >- 0xa66c86a47f4f81caae5d767e2d8a5a7def1a191d24eba5bd49f8767297cfe2e5 orderResponse: success: true errorMsg: '' orderID: >- 0xb9826fe87ddf21261eceaf513977cb5ea1ae31ac173210857c879cef936dfa2b transactionsHashes: - >- 0x39ac6726cf2cfb7814bdb2e04aeeea1d3bde2d1ce7e357f79a404cacb6984f35 status: matched takingAmount: '8.5' makingAmount: '5' '400': description: Bad request due to missing or invalid parameters content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: >- Unauthorized - Invalid or missing API key, or invalid/expired `signatureByEvmEoa` content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' servers: - url: https://api-v2.swaps.xyz/api description: Core Swap API Server components: schemas: EvmAddress: type: string pattern: ^0x[a-fA-F0-9]{40}$ description: EVM address (0x prefix + 40 hex characters) Hex: type: string pattern: ^0x[a-fA-F0-9]*$ description: Hex string with 0x prefix ErrorResponse: type: object required: - success - error properties: success: type: boolean description: Always false for error responses enum: - false example: false error: type: object required: - code - name - message - title - statusCode - timestamp properties: code: type: string description: Error type code for programmatic handling name: type: string description: Error class name message: type: string description: Detailed error message title: type: string description: Short, user-friendly error title statusCode: type: integer description: HTTP status code details: type: object description: Additional error details additionalProperties: true timestamp: type: string description: ISO 8601 timestamp when the error occurred securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: 'Limited demo key for API Reference: `5c951bc81da566bbd030ba8e20724063`.' ````