> ## 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. # Set your builder fee > Set this application's builder fee. The builder fee is an additional taker fee, in basis points, that this frontend charges its own users on top of Monaco's fee. The application is taken from the authenticated session; the caller must be the application's BuilderCodes payout wallet, and delegated-agent sessions are refused. `bps` must be between 0 and the current builder-fee cap (`builderFeeCapBps` on `GetBuildercodesConfig`) inclusive. The application must be enrolled in BuilderCodes with a payout address. At most two changes are allowed in any rolling 24 hours; changes Monaco makes on the application's behalf do not count. Setting the fee it already has is a no-op that succeeds and does not use up a change. The fee can be set while builder fees are switched off (`builderFeeEnabled` false): it is stored and nothing is charged until they are switched on. Once charged, a new fee applies to orders placed after the change within a few seconds; resting orders keep the fee they were placed with. A refused change is **HTTP 409** / **FAILED_PRECONDITION** when the application is not enrolled with a payout address or has no changes left (REST adds `details.nextChangeAllowedAt`), and **HTTP 400** / **INVALID_ARGUMENT** when `bps` is above the cap. ## OpenAPI ````yaml /proto-openapi/api/openapi.yaml put /api/v1/buildercodes/builder-fee 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/buildercodes/builder-fee: put: tags: - BuildercodeRewardsService - BuilderCodes summary: Set your builder fee description: |- Set this application's builder fee. The builder fee is an additional taker fee, in basis points, that this frontend charges its own users on top of Monaco's fee. The application is taken from the authenticated session; the caller must be the application's BuilderCodes payout wallet, and delegated-agent sessions are refused. `bps` must be between 0 and the current builder-fee cap (`builderFeeCapBps` on `GetBuildercodesConfig`) inclusive. The application must be enrolled in BuilderCodes with a payout address. At most two changes are allowed in any rolling 24 hours; changes Monaco makes on the application's behalf do not count. Setting the fee it already has is a no-op that succeeds and does not use up a change. The fee can be set while builder fees are switched off (`builderFeeEnabled` false): it is stored and nothing is charged until they are switched on. Once charged, a new fee applies to orders placed after the change within a few seconds; resting orders keep the fee they were placed with. A refused change is **HTTP 409** / **FAILED_PRECONDITION** when the application is not enrolled with a payout address or has no changes left (REST adds `details.nextChangeAllowedAt`), and **HTTP 400** / **INVALID_ARGUMENT** when `bps` is above the cap. operationId: set_builder_fee requestBody: content: application/json: schema: $ref: '#/components/schemas/SetBuilderFeeRequest' required: true responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/SetBuilderFeeResponse' '400': description: 'bps is above the current builder-fee cap (gRPC: INVALID_ARGUMENT)' '401': description: Authentication required '403': description: >- Refused: BuilderCodes is disabled, the caller is delegated, or the caller is not this application's payout wallet (gRPC: PERMISSION_DENIED) '404': description: 'Authenticated application not found (gRPC: NOT_FOUND)' '409': description: >- The application is not enrolled in BuilderCodes with a payout address, or it has already made two changes in the last 24 hours; the latter carries `details.nextChangeAllowedAt` (gRPC: FAILED_PRECONDITION) '500': description: Internal server error security: - monacoSignature: [] - monacoHttpSignature: [] components: schemas: SetBuilderFeeRequest: required: - bps type: object properties: bps: example: 10 maximum: 100 type: integer description: >- New builder fee in basis points, from 0 up to the current `builderFeeCapBps` inclusive. 0 stops charging a builder fee. format: uint32 additionalProperties: false SetBuilderFeeResponse: type: object properties: builderFeeBps: example: 10 maximum: 100 type: integer description: The builder fee now stored, in basis points. format: uint32 nullable: true previousBuilderFeeBps: example: 0 maximum: 100 type: integer description: >- The builder fee this change replaced, in basis points. Equal to `builderFeeBps` when the request set the fee it already had, which changes nothing. format: uint32 nullable: true changesRemaining: example: 1 maximum: 2 type: integer description: >- Builder-fee changes this application can still make in the current rolling 24 hours (at most 2). format: uint32 nullable: true nextChangeAllowedAt: type: string description: >- RFC 3339 time at which the next builder-fee change becomes allowed, or null while `changesRemaining` is above 0. format: date-time 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.