> ## Documentation Index > Fetch the complete documentation index at: https://docs.0xmonaco.com/llms.txt > Use this file to discover all available pages before exploring further. # Simulate fees for a potential order > Simulate fees for a potential order. Returns exact fee breakdown for a specific order before placing it, including Monaco protocol fees, application fees, total amounts, and the maximum quantity affordable at the given price. ## OpenAPI ````yaml /proto-openapi/api/openapi.yaml get /api/v1/fees/simulate openapi: 3.0.3 info: title: Monaco Protocol API description: REST API for the Monaco Protocol hybrid CLOB exchange. version: 1.0.0 servers: - url: https://staging.apimonaco.xyz description: Staging server (Testnet) security: [] tags: - name: AccountsService - name: ApplicationsService - name: AuthService - name: BuildercodeRewardsService - name: CopyTradingService - name: DelegatedAgentsService - name: FaucetService - name: FeesService - name: HealthService - name: ManagedMarketsService description: |- Wallet-authenticated maker assignments. The signed session must match both configured maker user and application. Owner IDs are process fences, never auth. Only wallet sessions are supported; delegated-agent sessions receive 403. - name: MarginAccountsService description: |- Current public isolated-margin semantics: - a user has one parent margin account per application scope - opening orders create or reuse isolated position buckets under that parent - parent account creation is handled internally by margin workflows - name: MarketService - name: OrderbookService - name: OrdersService - name: PositionsService description: |- Current public isolated-margin semantics: - positions link to a parent margin account and, when applicable, a bucket id - opening orders create or reuse isolated position buckets under the parent - users can open another isolated position by reusing the parent account with a different market bucket - name: PulseService - name: SweeperService - name: TraderCodeService - name: TradesService - name: WhitelistService - name: WithdrawalsService paths: /api/v1/fees/simulate: get: tags: - FeesService - Fees summary: Simulate fees for a potential order description: |- Simulate fees for a potential order. Returns exact fee breakdown for a specific order before placing it, including Monaco protocol fees, application fees, total amounts, and the maximum quantity affordable at the given price. operationId: simulate_fees parameters: - name: tradingPairId in: query schema: type: string minLength: 1 format: uuid description: Trading pair identifier (UUID) required: true - name: side in: query schema: type: string enum: - BUY - SELL minLength: 1 description: Order side required: true - name: price in: query schema: type: string minLength: 1 description: Price as decimal string required: true - name: quantity in: query schema: type: string minLength: 1 description: Quantity as decimal string required: true - name: orderType in: query schema: type: string enum: - LIMIT - MARKET - STOP_LOSS - TAKE_PROFIT - STOP_LIMIT - TRAILING_STOP minLength: 1 description: Order type - name: slippageToleranceBps in: query schema: type: integer format: int32 responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/SimulateFeesResponse' '400': description: Bad request (e.g., slippage with LIMIT order) '401': description: Authentication required '404': description: Trading pair or application not found '429': description: >- Read rate limit exceeded — every authenticated read draws one request from the account's read budget; retry after the interval in details.retryAfter '500': description: Internal server error security: - monacoSignature: [] - monacoHttpSignature: [] components: schemas: SimulateFeesResponse: type: object properties: notional: example: '20000.00' type: string description: Notional value (price x quantity) nullable: true monacoTakerFee: example: '20.00' type: string description: Monaco protocol taker fee in quote token nullable: true monacoMakerRebate: example: '-5.00' type: string description: Monaco maker rebate in quote token (negative) nullable: true applicationTakerFee: example: '10.00' type: string description: Application-specific taker fee in quote token nullable: true totalTakerFees: example: '30.00' type: string description: Total taker fees (monaco + application) nullable: true takerTotalPayment: example: '20030.00' type: string description: Total amount paid by taker (notional + fees) nullable: true makerTotalReceipt: example: '19995.00' type: string description: Total amount received by maker (notional - rebate) nullable: true buyOrderLockAmount: example: '20030.00' type: string description: >- Amount locked for buy orders. For MARKET orders, includes slippage buffer. nullable: true monacoTakerFeeBps: example: 10 deprecated: true type: integer description: >- DEPRECATED: whole-basis-points taker rate. An integer cannot represent fractional tiered rates (e.g. 6.5), so this echoes the flat trading_pairs column, NOT the tier-resolved rate the ledger charges. Kept for backward compatibility. Use monaco_taker_fee_bps_exact (or GET /api/v1/fees/tier). format: int32 nullable: true monacoMakerRebateBps: example: -2 deprecated: true type: integer description: >- DEPRECATED: whole-basis-points maker rebate. An integer cannot represent fractional tiered rebates (e.g. -1.15), so this echoes the flat trading_pairs column, NOT the tier-resolved rate. Kept for backward compatibility. Use monaco_maker_rebate_bps_exact (or GET /api/v1/fees/tier). format: int32 nullable: true applicationTakerFeeBps: example: 5 type: integer description: Application taker fee rate in basis points format: int32 nullable: true applicationName: example: Monaco Trading Frontend type: string description: Application display name nullable: true maxQuantity: example: '99.95' type: string description: >- Maximum quantity affordable at the given price, accounting for fees and slippage. Powers the 100% range input on the FE. nullable: true maxQuantityRaw: example: '99950000000000000000' type: string description: Maximum quantity in RAW (smallest unit) format nullable: true slippageToleranceBps: example: 500 type: integer description: Slippage tolerance used in the calculation (echoed back) format: int32 nullable: true monacoTakerFeeBpsExact: example: '6.5' type: string description: >- Tier-resolved Monaco taker fee rate as a decimal basis-points string — the exact rate the ledger charges this caller (equals monaco_taker_fee / notional). Fractional and per-tier, e.g. "6.5". Prefer this over the deprecated integer monaco_taker_fee_bps. nullable: true monacoMakerRebateBpsExact: example: '-1' type: string description: >- Tier-resolved Monaco maker rebate as a decimal basis-points string (negative is a rebate) — the exact rate the ledger credits this caller. Fractional and per-tier, e.g. "-1". Prefer this over the deprecated integer monaco_maker_rebate_bps. nullable: true securitySchemes: monacoSignature: type: apiKey description: >- Ed25519 session-key request signing. Every authenticated request carries three headers: `X-Monaco-PublicKey` (64-char lowercase-hex session public key), `X-Monaco-Timestamp` (Unix milliseconds, within 30s of server time), and `X-Monaco-Signature` (hex ed25519 signature). The signature is over `METHOD\npath?query\ntimestamp_ms\nSHA256_hex(body)`, where the body hash is the SHA-256 of the empty byte string when there is no body. Obtain the session keypair from `POST /api/v1/auth/challenge` followed by `POST /api/v1/auth/verify`. name: X-Monaco-Signature in: header monacoHttpSignature: type: apiKey description: >- RFC 9421 Ed25519 session-key request signatures. Send Signature-Input, Signature, and Content-Digest together; never combine them with X-Monaco-* credentials. The monaco signature covers @method, @path, @query, and content-digest in that order, with created (Unix seconds within 30s of server time), keyid (registered lowercase-hex session public key), and alg=ed25519 parameters. Content-Digest uses RFC 9530 sha-256 over the exact body bytes, including the empty body. Query coverage retains ordering and percent encoding. Timestamp freshness does not reject repeated identical requests; use endpoint idempotency where supported. Existing legacy signing remains supported during server-first migration; SDK RFC 9421 signing is opt-in. See https://docs.0xmonaco.com/reference/http-message-signatures for the complete profile and trust model. name: Signature in: header ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.