> ## Documentation Index > Fetch the complete documentation index at: https://docs.runonatlas.com/llms.txt > Use this file to discover all available pages before exploring further. # Upsert customer > Upsert customer by unique external ID (e.g. the customer ID in your system). Does not automatically subscribe the customer to the default plan if eligible. ## OpenAPI ````yaml https://platform.runonatlas.com/external/schema post /external/customers/upsert openapi: 3.0.0 info: title: Atlas API version: 1.0.0 servers: - url: https://platform.runonatlas.com security: [] paths: /external/customers/upsert: post: tags: - Customers summary: Upsert customer description: >- Upsert customer by unique external ID (e.g. the customer ID in your system). Does not automatically subscribe the customer to the default plan if eligible. requestBody: required: true content: application/json: schema: type: object properties: billingAddress1: type: string nullable: true minLength: 1 description: Billing address line 1 example: 123 Main St billingAddress2: type: string nullable: true minLength: 1 description: Billing address line 2 example: Apt 1 billingCity: type: string nullable: true minLength: 1 description: Billing city example: Anytown billingCountry: type: string nullable: true minLength: 1 description: Billing country example: US billingState: type: string nullable: true minLength: 1 description: Billing state example: CA billingZipCode: type: string nullable: true pattern: ^\d{5}(-\d{4})?$ description: Billing zip code. Must be 5 digits or 5+4 format. example: '12345' shippingAddress1: type: string nullable: true minLength: 1 description: Shipping address line 1 example: 123 Main St shippingAddress2: type: string nullable: true minLength: 1 description: Shipping address line 2 example: Apt 1 shippingCity: type: string nullable: true minLength: 1 description: Shipping city example: Anytown shippingCountry: type: string nullable: true minLength: 1 description: Shipping country example: US shippingState: type: string nullable: true minLength: 1 description: Shipping state example: CA shippingZipCode: type: string nullable: true pattern: ^\d{5}(-\d{4})?$ description: Shipping zip code. Must be 5 digits or 5+4 format. example: '12345' email: type: string nullable: true minLength: 1 format: email description: The email of the customer example: john.doe@example.com externalId: type: string minLength: 1 description: >- The external ID of the customer (e.g. the customer ID in your system) example: external-customer-id-123 name: type: string nullable: true minLength: 1 description: The name of the customer example: John Doe quickBooksId: type: string nullable: true minLength: 1 description: The QuickBooks ID of the customer example: quickbooks-customer-id-123 stripeId: type: string nullable: true minLength: 1 description: The Stripe ID of the customer example: stripe-customer-id-123 xeroId: type: string nullable: true minLength: 1 description: The Xero ID of the customer example: xero-customer-id-123 required: - externalId additionalProperties: false responses: '200': description: The customer that has been upserted. content: application/json: schema: type: object properties: billingAddress1: type: string nullable: true minLength: 1 description: Billing address line 1 example: 123 Main St billingAddress2: type: string nullable: true minLength: 1 description: Billing address line 2 example: Apt 1 billingCity: type: string nullable: true minLength: 1 description: Billing city example: Anytown billingCountry: type: string nullable: true minLength: 1 description: Billing country example: US billingState: type: string nullable: true minLength: 1 description: Billing state example: CA billingZipCode: type: string nullable: true pattern: ^\d{5}(-\d{4})?$ description: Billing zip code. Must be 5 digits or 5+4 format. example: '12345' shippingAddress1: type: string nullable: true minLength: 1 description: Shipping address line 1 example: 123 Main St shippingAddress2: type: string nullable: true minLength: 1 description: Shipping address line 2 example: Apt 1 shippingCity: type: string nullable: true minLength: 1 description: Shipping city example: Anytown shippingCountry: type: string nullable: true minLength: 1 description: Shipping country example: US shippingState: type: string nullable: true minLength: 1 description: Shipping state example: CA shippingZipCode: type: string nullable: true pattern: ^\d{5}(-\d{4})?$ description: Shipping zip code. Must be 5 digits or 5+4 format. example: '12345' createdAt: type: string format: date description: The date and time the customer was created example: '2021-01-01T00:00:00.000Z' email: type: string nullable: true minLength: 1 format: email description: The email of the customer example: john.doe@example.com externalId: type: string nullable: true minLength: 1 description: >- The external ID of the customer (e.g. the customer ID in your system) example: external-customer-id-123 id: type: string minLength: 1 description: The Atlas customer ID example: atlas-internal-customer-id-123 name: type: string nullable: true minLength: 1 description: The name of the customer example: John Doe updatedAt: type: string format: date description: The date and time the customer was last updated example: '2021-01-01T00:00:00.000Z' quickBooksId: type: string nullable: true minLength: 1 description: The QuickBooks ID of the customer example: quickbooks-customer-id-123 stripeId: type: string nullable: true minLength: 1 description: The Stripe ID of the customer example: stripe-customer-id-123 merchantId: type: string minLength: 1 description: The Atlas merchant ID example: atlas-internal-merchant-id-123 required: - createdAt - id - updatedAt - merchantId '400': description: >- There is an issue with the request data. See the response for more details. '401': description: Invalid API key provided. '409': description: >- A unique constraint violation occurred. See the response for more details. security: - apiKeyAuth: [] components: securitySchemes: apiKeyAuth: type: apiKey name: x-api-key in: header description: >- You can obtain this key from the Atlas dashboard. It must be of type `secret` ````