> ## Documentation Index > Fetch the complete documentation index at: https://docs.stabyl.com/llms.txt > Use this file to discover all available pages before exploring further. # Estimate market order > Estimates visible-depth execution, slippage, and an optional partner client spread for a market order. The result is non-binding and does not alter Stabyl execution or fees. ## OpenAPI ````yaml /openapi/openapi.json post /partner/exchange/orders/estimate openapi: 3.1.0 info: title: Stabyl API description: >- REST API for approved Stabyl accounts to automate exchange, wallet, and non-production simulation workflows. contact: name: Stabyl Support email: support@stabyl.com license: name: Proprietary version: 1.0.0 servers: - url: https://api.stabyl.com/v1 description: Production - url: https://api-staging.stabyl.com/v1 description: Staging security: [] tags: - name: Exchange description: Trading market data and order management for account automation. - name: Wallets description: >- Supported routes, deposit destinations, balances, transactions, and saved recipients. - name: Webhooks description: >- Outbound event delivery configuration and eventually consistent delivery history. Verify Standard Webhooks webhook-id, webhook-timestamp, and webhook-signature headers against the unchanged raw request body before parsing JSON. - name: Simulation description: Non-production endpoints for testing integration behavior. paths: /partner/exchange/orders/estimate: post: tags: - Exchange summary: Estimate market order description: >- Estimates visible-depth execution, slippage, and an optional partner client spread for a market order. The result is non-binding and does not alter Stabyl execution or fees. operationId: post_partner_exchange_orders_estimate requestBody: content: application/json: schema: $ref: '#/components/schemas/MarketOrderEstimateRequest' required: true responses: '200': description: Market-order estimate content: application/json: schema: type: object required: - status - data properties: data: $ref: '#/components/schemas/MarketOrderEstimateResponse' status: type: string enum: - success example: data: {} status: success '400': description: Invalid side, quantity, spread, or unavailable liquidity content: application/json: schema: type: object required: - status - error properties: error: type: object required: - code - message properties: code: type: string example: VALIDATION_FAILED message: type: string example: invalid request parameters status: type: string enum: - error example: error: code: VALIDATION_FAILED message: invalid request parameters status: error '401': description: Unauthorized content: application/json: schema: type: object required: - status - error properties: error: type: object required: - code - message properties: code: type: string example: UNAUTHORIZED message: type: string example: missing X-Api-Key header status: type: string enum: - error example: error: code: UNAUTHORIZED message: missing X-Api-Key header status: error security: - api_key: [] components: schemas: MarketOrderEstimateRequest: type: object description: Request for a non-binding market-order execution estimate. required: - pair_id - side - quantity properties: business_bps: type: - integer - 'null' format: int32 description: >- Optional partner spread applied to the estimated execution price for a client quote. This does not alter Stabyl execution or fees. example: 25 maximum: 10000 minimum: 0 pair_id: type: string description: Trading pair identifier. example: USD/NGN quantity: type: string description: Quantity in base currency. example: '100.00' side: type: string description: 'Order side: "buy" consumes asks and "sell" consumes bids.' example: buy MarketOrderEstimateResponse: type: object description: Non-binding market-order execution and partner-quote estimate. required: - pair_id - side - quantity - estimated_fill_quantity - sufficient_liquidity - reference_price - estimated_average_price - estimated_slippage_bps - business_bps - client_quote_price - estimated_notional - client_quote_notional - orderbook_sequence - estimated_at properties: business_bps: type: integer format: int32 description: Partner-supplied spread used to calculate `client_quote_price`. minimum: 0 client_quote_notional: type: string description: Client-facing notional after applying `business_bps`. client_quote_price: type: string description: >- Average price with the partner spread applied (buy: add; sell: subtract). estimated_at: type: string description: Timestamp of the source order-book snapshot. estimated_average_price: type: string description: Quantity-weighted average execution price across visible levels. estimated_fill_quantity: type: string description: Quantity covered by the currently visible order-book depth. estimated_notional: type: string description: Estimated Stabyl execution notional for the covered quantity. estimated_slippage_bps: type: integer format: int32 description: Estimated adverse movement from the best price, in basis points. minimum: 0 orderbook_sequence: type: integer format: int64 description: Order-book sequence used for the estimate. minimum: 0 pair_id: type: string quantity: type: string description: Requested base quantity. reference_price: type: string description: Current best price on the consumed side of the book. side: type: string sufficient_liquidity: type: boolean description: Whether visible depth covers the entire request. securitySchemes: api_key: type: apiKey in: header name: X-Api-Key description: >- API credential. Withdrawal quote and submit operations additionally require the documented Ed25519 timestamp, nonce, and signature headers. x-default: sb_test_your_key ````