> ## Documentation Index > Fetch the complete documentation index at: https://docs.monaco.com/llms.txt > Use this file to discover all available pages before exploring further. # Preview a Contact Merge > Read-only preview of merging the contact `source_contact_id` into the contact in the path. Nothing is changed. Returns how the kept contact will look, which of its empty fields the source fills, what moves over (sequences, tasks, tags, audience memberships, opportunity links, custom field values) and the live sequences that would be stopped. Requires only the `api:read` scope. Both contacts must be on the same account, and when both have an email or both have a LinkedIn URL those must match; otherwise the request is rejected with 422 `merge_invalid` and a message naming the rule. ## OpenAPI ````yaml https://api.monaco.com/openapi.json post /v1/contacts/{contact_id}/merge/preview openapi: 3.2.1 info: title: Monaco Public API description: Public API for Monaco version: 1.0.0 servers: - url: https://api.monaco.com security: [] paths: /v1/contacts/{contact_id}/merge/preview: post: tags: - Contacts summary: Preview a Contact Merge description: >- Read-only preview of merging the contact `source_contact_id` into the contact in the path. Nothing is changed. Returns how the kept contact will look, which of its empty fields the source fills, what moves over (sequences, tasks, tags, audience memberships, opportunity links, custom field values) and the live sequences that would be stopped. Requires only the `api:read` scope. Both contacts must be on the same account, and when both have an email or both have a LinkedIn URL those must match; otherwise the request is rejected with 422 `merge_invalid` and a message naming the rule. operationId: preview_contact_merge parameters: - name: contact_id in: path required: true schema: type: string format: uuid title: Contact Id requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/ContactMergePreviewRequest' responses: '200': description: Successful Response content: application/json: schema: $ref: >- #/components/schemas/PublicItemResponse_ContactMergePreviewResponse_ '422': description: The merge request is invalid content: application/json: schema: $ref: '#/components/schemas/ContactMergeErrorResponse' 4XX: description: Client error content: application/json: schema: $ref: '#/components/schemas/PublicErrorResponse' components: schemas: ContactMergePreviewRequest: properties: source_contact_id: type: string format: uuid title: Source Contact Id description: >- ID of the contact to merge into the contact in the path. It is deleted when the merge is applied. Both contacts must be on the same account. additionalProperties: false type: object required: - source_contact_id title: ContactMergePreviewRequest PublicItemResponse_ContactMergePreviewResponse_: properties: data: $ref: '#/components/schemas/ContactMergePreviewResponse' meta: $ref: '#/components/schemas/ResponseMeta' type: object required: - data title: PublicItemResponse[ContactMergePreviewResponse] ContactMergeErrorResponse: properties: error: $ref: '#/components/schemas/ContactMergeErrorDetail' type: object required: - error title: ContactMergeErrorResponse PublicErrorResponse: properties: error: $ref: '#/components/schemas/ErrorDetail' type: object required: - error title: PublicErrorResponse ContactMergePreviewResponse: properties: target_contact: $ref: '#/components/schemas/ContactMergeContactSummary' source_contact: $ref: '#/components/schemas/ContactMergeContactSummary' merged_contact: $ref: '#/components/schemas/ContactMergeContactSummary' description: The contact in the path as it will look after the merge fields_filled_from_source: items: type: string type: array title: Fields Filled From Source description: Empty fields on the contact in the path that take the source's value notes_appended: type: boolean title: Notes Appended description: True when the source's notes will be appended counts: $ref: '#/components/schemas/ContactMergeCounts' blocking_sequences: items: $ref: '#/components/schemas/MergeBlockingSequence' type: array title: Blocking Sequences requires_sequence_stop: type: boolean title: Requires Sequence Stop description: True when applying the merge would stop live sequences type: object required: - target_contact - source_contact - merged_contact - fields_filled_from_source - notes_appended - counts - blocking_sequences - requires_sequence_stop title: ContactMergePreviewResponse ResponseMeta: properties: timestamp: type: string format: date-time title: Timestamp description: Server timestamp of the response type: object title: ResponseMeta ContactMergeErrorDetail: properties: code: type: string title: Code description: Machine-readable error code examples: - not_found message: type: string title: Message description: Human-readable error message examples: - Resource not found blocking_sequence_count: anyOf: - type: integer - type: 'null' title: Blocking Sequence Count description: >- For `sequence_stop_confirmation_required`, how many live sequences would stop type: object required: - code - message title: ContactMergeErrorDetail ErrorDetail: properties: code: type: string title: Code description: Machine-readable error code examples: - not_found message: type: string title: Message description: Human-readable error message examples: - Resource not found type: object required: - code - message title: ErrorDetail ContactMergeContactSummary: properties: id: type: string title: Id name: anyOf: - type: string - type: 'null' title: Name email: anyOf: - type: string - type: 'null' title: Email linkedin_url: anyOf: - type: string - type: 'null' title: Linkedin Url title: anyOf: - type: string - type: 'null' title: Title archived: type: boolean title: Archived default: false type: object required: - id title: ContactMergeContactSummary ContactMergeCounts: properties: plays_moved: type: integer title: Plays Moved user_tasks_moved: type: integer title: User Tasks Moved tags_added: type: integer title: Tags Added audience_memberships_moved: type: integer title: Audience Memberships Moved opportunity_links_moved: type: integer title: Opportunity Links Moved custom_fields_filled: type: integer title: Custom Fields Filled type: object required: - plays_moved - user_tasks_moved - tags_added - audience_memberships_moved - opportunity_links_moved - custom_fields_filled title: ContactMergeCounts MergeBlockingSequence: properties: sequence_id: type: string title: Sequence Id status: type: string title: Status contact: $ref: '#/components/schemas/MergeContactSummary' name: anyOf: - type: string - type: 'null' title: Name campaign_name: anyOf: - type: string - type: 'null' title: Campaign Name type: object required: - sequence_id - status - contact title: MergeBlockingSequence MergeContactSummary: properties: id: type: string title: Id name: anyOf: - type: string - type: 'null' title: Name email: anyOf: - type: string - type: 'null' title: Email type: object required: - id title: MergeContactSummary ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.