> ## Documentation Index > Fetch the complete documentation index at: https://docs.ycloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Update a phone number business username > Requests a Business Username update for a WhatsApp business phone number. The requested username may require Meta review before it becomes active. If Meta accepts or reserves the request for review, the response status is usually `reserved`; `pending_review` is kept only as a legacy compatibility value. If Meta returns an error, YCloud returns the error and does not change the stored Business Username state. The `username` value is a plain username without `@`. YCloud trims leading and trailing whitespace and normalizes the value to lowercase before validation and submission. ## OpenAPI ````yaml /openapi/endpoints/ycloud-api-v2.yaml patch /whatsapp/phoneNumbers/{wabaId}/{phoneNumber}/businessUsername openapi: 3.0.0 info: description: >- The [YCloud](https://ycloud.com) API is organized around [REST](https://en.wikipedia.org/wiki/Representational_state_transfer). Our API is designed to have predictable, resource-oriented URLs, return [JSON](https://www.json.org) responses, and use standard HTTP response codes and verbs. version: v2 title: YCloud API termsOfService: https://ycloud.com/terms-service contact: email: service@ycloud.com servers: - url: https://api.ycloud.com/v2 description: Base URL security: - api_key: [] tags: - name: Balance - name: Contacts - name: Custom Events - name: Emails - name: SMS - name: Unsubscribers - name: Verify - name: Voices - name: Webhook Endpoints - name: WhatsApp Business Accounts - name: WhatsApp Inbound Messages - name: WhatsApp Media - name: WhatsApp Messages - name: WhatsApp Blocked Users - name: WhatsApp Groups - name: WhatsApp Calling - name: WhatsApp Phone Numbers - name: WhatsApp Templates - name: WhatsApp Flows - name: Meta Business Agent - name: WhatsApp Group Messages externalDocs: description: Homepage url: https://ycloud.com paths: /whatsapp/phoneNumbers/{wabaId}/{phoneNumber}/businessUsername: patch: tags: - WhatsApp Phone Numbers summary: Update a phone number business username description: >- Requests a Business Username update for a WhatsApp business phone number. The requested username may require Meta review before it becomes active. If Meta accepts or reserves the request for review, the response status is usually `reserved`; `pending_review` is kept only as a legacy compatibility value. If Meta returns an error, YCloud returns the error and does not change the stored Business Username state. The `username` value is a plain username without `@`. YCloud trims leading and trailing whitespace and normalizes the value to lowercase before validation and submission. operationId: whatsapp_phone_number-update-business-username parameters: - name: wabaId in: path description: WhatsApp Business Account ID. required: true schema: type: string example: whatsapp-business-account-id - name: phoneNumber in: path description: Phone number in [E.164](https://en.wikipedia.org/wiki/E.164) format. required: true schema: type: string example: '+16315551111' requestBody: content: application/json: schema: $ref: '#/components/schemas/WhatsappBusinessUsernameUpdateRequest' required: true responses: '200': description: Successfully submitted the update request. content: application/json: schema: $ref: '#/components/schemas/WhatsappBusinessUsername' '400': description: Bad request. Invalid request parameters. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: The requested resource does not exist. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' components: schemas: WhatsappBusinessUsernameUpdateRequest: type: object required: - username properties: username: type: string description: >- Business Username to request for the phone number. Send the plain username without `@`. YCloud trims leading and trailing whitespace and normalizes the value to lowercase before validation and submission. The value must be 3-35 characters, contain only English letters, numbers, periods, and underscores, and contain at least one English letter. It must not start or end with a period, contain consecutive periods, start with `www`, or end with common domain suffixes such as `.com`, `.org`, `.net`, `.int`, `.edu`, `.gov`, `.mil`, `.us`, `.in`, or `.html`. minLength: 3 maxLength: 35 pattern: ^[A-Za-z0-9._]+$ example: acme.support WhatsappBusinessUsername: type: object description: Business Username state for a WhatsApp business phone number. properties: id: type: string description: Phone number ID. example: '1234567890123456' wabaId: type: string description: WhatsApp Business Account ID. example: whatsapp-business-account-id phoneNumber: type: string description: Phone number in [E.164](https://en.wikipedia.org/wiki/E.164) format. example: '+16315551111' displayPhoneNumber: type: string description: Display phone number. example: +1 631-555-1111 businessUsername: type: string description: Active Business Username. The value is a plain username without `@`. example: acme.support businessUsernameStatus: $ref: '#/components/schemas/WhatsappBusinessUsernameStatus' requestedBusinessUsername: type: string description: >- Last requested Business Username that is still under review. This value can coexist with an active `businessUsername` while the new request is pending. example: acme.help businessUsernameUpdatedAt: type: string format: date-time description: The time when the Business Username state was last updated. example: '2026-05-26T12:00:00.000Z' ErrorResponse: type: object required: - error properties: error: $ref: '#/components/schemas/Error' description: >- Contains the error code and human-readable message for the API error. WhatsappBusinessUsernameStatus: type: string description: >- Business Username state for a WhatsApp business phone number. - `not_set`: No active or pending Business Username exists. - `active`: A Business Username is active. - `reserved`: A requested Business Username is reserved by Meta and may still be under review. - `pending_review`: Legacy compatibility value for an under-review request. New writes use `reserved`. If an active username exists while a new request is reserved or under review, `businessUsernameStatus` is `reserved`, `businessUsername` contains the still-active username, and `requestedBusinessUsername` contains the requested username. enum: - not_set - active - pending_review - reserved Error: type: object required: - status - code properties: status: type: integer format: int32 pattern: '[45]\d{2}' description: >- HTTP status code, [RFC 7231, Section 6](https://datatracker.ietf.org/doc/html/rfc7231#section-6). It conveys the HTTP status code used for the convenience of the consumer. example: 404 code: type: string description: >- One of a server-defined error codes. Some `4xx` errors that could be handled programmatically include an error code that briefly explains the error reported. example: NOT_FOUND message: type: string description: >- A human-readable representation of the error. It is intended as an aid to developers and is not suitable for exposure to end users. example: The requested resource does not exist. target: type: string description: The target of the error. example: '' docUrl: type: string description: A URL to more information about the error. example: '' requestId: type: string description: >- Each API request has an associated request ID. It conveys the response header `YCloud-Request-ID` used for the convenience of the consumer. example: req_1KjtKI80IKoaJNa6n6p whatsappApiError: $ref: '#/components/schemas/WhatsappApiError' description: >- The original error object returned by WhatsApp. See [Handling Errors](https://developers.facebook.com/docs/graph-api/guides/error-handling), [Cloud API Error Codes](https://developers.facebook.com/docs/whatsapp/cloud-api/support/error-codes). Note: This field is returned if we tried to request the WhatsApp Business API and got an error response. metaBusinessAgentApiError: $ref: '#/components/schemas/MetaBusinessAgentApiError' description: >- Sanitized upstream details returned when a Meta Business Agent request fails. WhatsappApiError: type: object description: >- The original error object returned by WhatsApp. See [Handling Errors](https://developers.facebook.com/docs/graph-api/guides/error-handling), [Cloud API Error Codes](https://developers.facebook.com/docs/whatsapp/cloud-api/support/error-codes). required: - message - code properties: message: type: string description: A human-readable description of the error. example: HSM Template creation failed code: type: string description: An error code. example: 200002 type: type: string description: Error type. example: OAuthException is_transient: type: boolean description: Whether the error is transient. example: false error_subcode: type: string description: Additional code about the error. example: 2388109 error_user_msg: type: string description: >- The message to display to the user. The language of the message is based on the locale of the API request. example: This message template cannot be created. error_user_title: type: string description: >- The title of the dialog, if shown. The language of the message is based on the locale of the API request. example: Message Cannot Be Submitted fbtrace_id: type: string description: >- Internal support identifier. When reporting a bug related to a Graph API call, include the fbtrace_id to help us find log data for debugging. example: AVGjJ7ia2zJkrHG error_data: description: >- Additional data about the error. A string or map. - For template APIs, this field is a string describing the reason for the error. - For message APIs, this field is a map with property `details` describing the reason for the error. oneOf: - type: string - type: object additionalProperties: true MetaBusinessAgentApiError: type: object description: Sanitized details from a failed Meta Business Agent upstream request. properties: title: type: string detail: type: string type: type: string status: type: integer format: int32 requestId: type: string securitySchemes: api_key: type: apiKey name: X-API-Key in: header ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.