> ## 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. # Preview copying a lead trader's open positions > Preview copying a leader's open positions. What a follow with these terms would open if it set `copyExisting`, as totals only: the estimated margin and fees, and how many of the leader's positions would and would not be copied. It names no pair, side or reason. Read-only; nothing is placed or reserved. The same session rules and follow terms rules as following apply, it is refused while copy trading is off, and it spends the order-risk preview budget. At most 64 positions are sized; `truncated` says when more matched. ## OpenAPI ````yaml /proto-openapi/api/openapi.yaml post /api/v1/copy-trading/follows/preview 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/copy-trading/follows/preview: post: tags: - CopyTradingService - Copy Trading summary: Preview copying a lead trader's open positions description: |- Preview copying a leader's open positions. What a follow with these terms would open if it set `copyExisting`, as totals only: the estimated margin and fees, and how many of the leader's positions would and would not be copied. It names no pair, side or reason. Read-only; nothing is placed or reserved. The same session rules and follow terms rules as following apply, it is refused while copy trading is off, and it spends the order-risk preview budget. At most 64 positions are sized; `truncated` says when more matched. operationId: preview_follow requestBody: content: application/json: schema: $ref: '#/components/schemas/PreviewFollowRequest' required: true responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/PreviewFollowResponse' '400': description: >- Invalid request, or terms a follow would refuse (the message names the rule) '401': description: Authentication required '403': description: Delegated agent or sub-account sessions cannot follow '404': description: Lead trader not found '409': description: Copy trading is not available '429': description: >- Read or order-risk preview rate limit exceeded; retry after the interval in details.retryAfter '500': description: Internal server error '503': description: Matching engine unavailable or its preview capacity is busy; retry security: - monacoSignature: [] - monacoHttpSignature: [] components: schemas: PreviewFollowRequest: type: object properties: leader: example: alpha_trader type: string description: The leader's custom TraderCode handle nullable: true marginModePolicy: example: FOLLOW type: string description: FOLLOW (default), CROSS or ISOLATED nullable: true sizingMode: example: PROPORTIONAL type: string description: PROPORTIONAL (default) or FIXED_MARGIN nullable: true sizingParam: type: string description: >- Margin per leader order in quote units; required for FIXED_MARGIN, omitted otherwise nullable: true leverageMode: example: FOLLOW type: string description: FOLLOW (default) or FIXED nullable: true fixedLeverage: type: string description: Leverage for every copy; required for FIXED, omitted otherwise nullable: true allocation: example: '1000' type: string description: Collateral the copy account would start with, in quote units nullable: true markets: allOf: - $ref: '#/components/schemas/CopyMarketFilter' description: Markets to copy; omit to copy every market the leader trades. nullable: true PreviewFollowResponse: type: object properties: estimatedMargin: example: '125.40' type: string description: >- Estimated collateral the copied positions would reserve at placement, in quote units, rounded up to cents nullable: true estimatedFee: example: '0.35' type: string description: >- Estimated taker fees of the copies, in quote units, rounded up to cents nullable: true copiedPositions: example: 2 type: integer description: The leader's positions (in the copied markets) that would be copied format: uint32 nullable: true skippedPositions: example: 1 type: integer description: >- The leader's positions (in the copied markets) that would not be copied format: uint32 nullable: true truncated: type: boolean description: >- True when the leader holds more positions in the copied markets than one preview sizes (64); the totals and counts cover the first ones only nullable: true description: >- What following with `copyExisting` would open, as totals only. The caller of a preview is never a follower of the leader (copyExisting applies only on a create), so the response names no pair, side, size, mark or skip reason, and a leader whose positions cannot be copied at all gives `copiedPositions = 0` with no reason. The totals are rounded UP to cents (the settlement currency's display precision). A residual aggregate signal remains: the counts and the rounded totals across varied allocations bound the size of the leader's book, never its markets or direction. CopyMarketFilter: type: object properties: tradingPairIds: type: array items: type: string minLength: 1 format: uuid description: Trading pair UUIDs to copy (at most 256); empty means every market. nullable: true description: A follow's market filter. 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 ````