--- title: "Preview a customer merge · Customers · COUNT Partner API" description: "Reports what a merge would move, without changing anything. POST /partners/customers/merge/preview" canonical: "https://developers.getcount.com/reference/customers/preview-merge-customers" source: "https://developers.getcount.com/reference/customers/preview-merge-customers" --- [Customers](https://developers.getcount.com/reference/customers) / Preview a customer merge # Preview a customer merge POST `/partners/customers/merge/preview` Reports what a merge would move, without changing anything. Read-only. Returns the target and source customers plus a count of every record that would be repointed at the target, so you can show the user the blast radius before committing. Run this before Merge customers — the merge itself cannot be undone through the API. HMAC signature + Bearer access token [Try this request](https://developers.getcount.com/tools/try-it?method=POST&path=%2Fpartners%2Fcustomers%2Fmerge%2Fpreview&body=%7B%0A++%22targetCustomerUuid%22%3A+%22dfa3219e-6af8-4c53-997a-037534f63a35%22%2C%0A++%22sourceCustomerUuids%22%3A+%5B%0A++++%227c8d9e0f-1a2b-4c3d-8e4f-5a6b7c8d9e0f%22%0A++%5D%0A%7D) [Invoices API](https://developers.getcount.com/reference/invoices) [Projects API](https://developers.getcount.com/reference/projects) [Recurring Invoice Templates API](https://developers.getcount.com/reference/recurring-invoice-templates) #### Request body `targetCustomerUuid` uuid required The customer that survives the merge and receives every reference. `sourceCustomerUuids` array required Customers to fold into the target. Non-empty, capped at 100 per request. The target UUID is ignored if it also appears here, and duplicates are collapsed. #### Responses `200` What the merge would affect. `affectedItems` counts records on the source customers only. `400` targetCustomerUuid missing, sourceCustomerUuids empty or over 100 entries, no distinct source left after the target is excluded, or a source is a firm-managed customer. `404` The target or one of the source customers was not found in this workspace. `401` Missing or invalid HMAC signature, expired timestamp, or invalid Bearer token. [Troubleshoot](https://developers.getcount.com/getting-started/errors#error-401) `403` The credential does not have access to this workspace or resource. [Troubleshoot](https://developers.getcount.com/getting-started/errors#error-403) `429` Rate limit exceeded (100 requests per minute per clientId). Retry after the Retry-After header. [Troubleshoot](https://developers.getcount.com/getting-started/errors#error-429) [Previous GET Get customer revenue overview](https://developers.getcount.com/reference/customers/get-customer-revenue-overview) [Next POST Merge customers](https://developers.getcount.com/reference/customers/merge-customers) POST `https://api.getcount.com/partners/customers/merge/preview` Request ```javascript import crypto from 'node:crypto'; const BASE_URL = 'https://api.getcount.com'; const CLIENT_ID = process.env.COUNT_CLIENT_ID; const CLIENT_SECRET = process.env.COUNT_CLIENT_SECRET; const ACCESS_TOKEN = process.env.COUNT_ACCESS_TOKEN; const method = 'POST'; const signingPath = '/customers/merge/preview'; const timestamp = Math.floor(Date.now() / 1000).toString(); const body = { "targetCustomerUuid": "dfa3219e-6af8-4c53-997a-037534f63a35", "sourceCustomerUuids": [ "7c8d9e0f-1a2b-4c3d-8e4f-5a6b7c8d9e0f" ] }; const bodyString = JSON.stringify(body); const bodyHash = crypto.createHash('sha256').update(bodyString).digest('hex'); const baseString = `${method}:${signingPath}:${timestamp}:${bodyHash}`; const signature = crypto.createHmac('sha256', CLIENT_SECRET).update(baseString).digest('hex'); const response = await fetch(`${BASE_URL}/partners/customers/merge/preview`, { method, headers: { 'x-client-id': CLIENT_ID, 'x-timestamp': timestamp, 'x-signature': signature, 'Content-Type': 'application/json', Authorization: `Bearer ${ACCESS_TOKEN}`, }, body: bodyString, }); console.log(await response.json()); ``` Response · 200 ```json { "status": "success", "message": "Successfully generated merge preview", "data": { "result": { "targetCustomer": { "id": "dfa3219e-6af8-4c53-997a-037534f63a35", "customer": "Acme Corporation", "email": "contact@acme.com", "mainPhone": "+1234567890", "website": "https://acme.com", "status": "active", "notes": "Preferred customer. Net-30 terms.", "paymentTerm": "net30", "taxNumber": null, "taxAutoCalculate": false, "taxExcluded": false, "contactName": "John Doe", "billingAddress": { "id": "0b2c1f5e-7a9d-4f2b-9c1e-2a4b6d8e0f12", "street": "123 Main St", "city": "San Francisco", "state": "CA", "zipCode": "94102", "country": "USA" }, "shippingAddress": null, "contacts": [ { "id": "a5da3577-bf85-4e3a-aa73-df85ca69bc67", "firstName": "John", "lastName": "Doe", "email": "john@acme.com", "phone": "+1234567890", "isPrimary": true } ], "taxes": [], "salesRep": null, "createdAt": "2026-01-15T10:30:00.000Z", "updatedAt": "2026-01-28T14:22:30.000Z" }, "sourceCustomers": [ { "id": "7c8d9e0f-1a2b-4c3d-8e4f-5a6b7c8d9e0f", "customer": "Acme Corp.", "email": "contact@acme.com", "mainPhone": "+1234567890", "website": "https://acme.com", "status": "active", "notes": "Preferred customer. Net-30 terms.", "paymentTerm": "net30", "taxNumber": null, "taxAutoCalculate": false, "taxExcluded": false, "contactName": "John Doe", "billingAddress": { "id": "0b2c1f5e-7a9d-4f2b-9c1e-2a4b6d8e0f12", "street": "123 Main St", "city": "San Francisco", "state": "CA", "zipCode": "94102", "country": "USA" }, "shippingAddress": null, "contacts": [ { "id": "a5da3577-bf85-4e3a-aa73-df85ca69bc67", "firstName": "John", "lastName": "Doe", "email": "john@acme.com", "phone": "+1234567890", "isPrimary": true } ], "taxes": [], "salesRep": null, "createdAt": "2026-01-15T10:30:00.000Z", "updatedAt": "2026-01-28T14:22:30.000Z" } ], "affectedItems": { "transactions": 18, "journalEntries": 2, "invoices": 7, "estimates": 1, "creditMemos": 0, "documents": 3, "projects": 1, "recurringInvoiceTemplates": 0, "timeEntries": 12, "bills": 0, "vendorMemos": 0, "smsMessages": 0, "customerContacts": 2, "customerAddresses": 1, "customerTaxes": 0, "customerStatments": 0, "automationActions": 0, "automationConditionCustomers": 0, "reportHistoryCustomers": 0, "customerNotes": 4, "sourceCustomersToDelete": 1 }, "note": "All references from Acme Corp. will be moved to Acme Corporation. Source customer(s) will be soft deleted (marked as inactive and deleted)." } } } ```