# Add campaign contacts (/docs/api-reference/whatsapp/addWhatsappCampaignContacts) > Add one contact, or up to 500 at once. On a draft they are stored for launch. On a running campaign they are sent now. A contact already in the campaign is skipped, so a retry is safe. Each contact needs a phone_number; every other key is kept and can fill a template parameter through variable_mapping. > **Set up WhatsApp first.** Connect a WhatsApp number in the dashboard or with [Connect numbers](/docs/api-reference/whatsapp/importWhatsappNumbers). Included on every paid plan. [See plans](https://omnidim.io/pricing). **POST** `/whatsapp/campaigns/{campaign_id}/contacts` Add one contact, or up to 500 at once. On a draft they are stored for launch. On a running campaign they are sent now. A contact already in the campaign is skipped, so a retry is safe. Each contact needs a `phone_number`; every other key is kept and can fill a template parameter through `variable_mapping`. ```yaml operationId: addWhatsappCampaignContacts parameters: - in: path name: campaign_id required: true schema: type: integer description: Id of a WhatsApp campaign, from `listWhatsappCampaigns`. requestBody: required: true content: application/json: schema: description: One contact object, or an array of 1 to 500. oneOf: - type: object description: | One contact. `phone_number` is required. Any other key is kept on the contact and can fill a template parameter through `variable_mapping`. required: - phone_number properties: phone_number: type: string description: The customer's number in international format, such as `+15551234567`. contact_name: type: string description: A name for your team. `name` works too. additionalProperties: true - type: array maxItems: 500 items: type: object description: | One contact. `phone_number` is required. Any other key is kept on the contact and can fill a template parameter through `variable_mapping`. required: - phone_number properties: phone_number: type: string description: The customer's number in international format, such as `+15551234567`. contact_name: type: string description: A name for your team. `name` works too. additionalProperties: true example: - phone_number: '+15551234567' contact_name: Demo User - phone_number: '+15557654321' contact_name: Second User responses: '200': description: What happened to each contact. content: application/json: schema: type: object description: What happened to each contact you sent. properties: imported: type: integer skipped_invalid: type: integer skipped_duplicate: type: integer total_submitted: type: integer contacts: type: array description: One entry per contact that was accepted or already existed. items: type: object properties: index: type: integer contact_id: type: integer duplicate: type: boolean errors: type: array description: One entry per contact that was skipped. items: type: object properties: index: type: integer error: type: string '400': description: '`invalid_json`: the body is not one contact object or an array of 1 to 500.' content: application/json: schema: type: object description: | The error envelope for every WhatsApp route. Some errors add keys: `fields` (the template parameters a send still needs), `ref` (a 500's support reference) and `failed` (on `import_failed`). properties: error: type: string description: Machine-readable category, such as `invalid_request`. error_description: type: string description: Human-readable explanation. code: type: string description: Stable, specific reason, such as `window_closed`. request_id: type: string description: >- Correlates this response with the server log. Also sent as the `X-Request-Id` header. fields: type: array items: type: string description: >- On a template send missing parameters (`missing_fields`), the field keys you still need. ref: type: string description: On a `500`, the reference to quote to support. failed: type: array items: type: object properties: phone_number_id: type: string message: type: string example: >- This WhatsApp number is already connected to another account. Disconnect it there first, then import it again. Contact support if you cannot access that account. description: On `import_failed`, each number and why it could not be connected. '401': description: Missing or invalid API key. content: application/json: schema: type: object description: | The error envelope for every WhatsApp route. Some errors add keys: `fields` (the template parameters a send still needs), `ref` (a 500's support reference) and `failed` (on `import_failed`). properties: error: type: string description: Machine-readable category, such as `invalid_request`. error_description: type: string description: Human-readable explanation. code: type: string description: Stable, specific reason, such as `window_closed`. request_id: type: string description: >- Correlates this response with the server log. Also sent as the `X-Request-Id` header. fields: type: array items: type: string description: >- On a template send missing parameters (`missing_fields`), the field keys you still need. ref: type: string description: On a `500`, the reference to quote to support. failed: type: array items: type: object properties: phone_number_id: type: string message: type: string example: >- This WhatsApp number is already connected to another account. Disconnect it there first, then import it again. Contact support if you cannot access that account. description: On `import_failed`, each number and why it could not be connected. example: error: unauthorized error_description: Missing or invalid API key code: invalid_api_key request_id: req_6e2b9d4f1a38 '403': description: | `feature_not_enabled` when your plan or role cannot use WhatsApp, `permission_denied` when the key's user cannot make changes, or `service_unavailable` when the account is on hold. content: application/json: schema: type: object description: | The error envelope for every WhatsApp route. Some errors add keys: `fields` (the template parameters a send still needs), `ref` (a 500's support reference) and `failed` (on `import_failed`). properties: error: type: string description: Machine-readable category, such as `invalid_request`. error_description: type: string description: Human-readable explanation. code: type: string description: Stable, specific reason, such as `window_closed`. request_id: type: string description: >- Correlates this response with the server log. Also sent as the `X-Request-Id` header. fields: type: array items: type: string description: >- On a template send missing parameters (`missing_fields`), the field keys you still need. ref: type: string description: On a `500`, the reference to quote to support. failed: type: array items: type: object properties: phone_number_id: type: string message: type: string example: >- This WhatsApp number is already connected to another account. Disconnect it there first, then import it again. Contact support if you cannot access that account. description: On `import_failed`, each number and why it could not be connected. example: error: forbidden error_description: You do not have permission to make changes to WhatsApp. code: permission_denied request_id: req_9f2c1a4b7d3e '404': description: | No number, conversation, message, template, media upload, agent, campaign, contact or opt-out with that id in your workspace. `code` says which. Another workspace's id gives the same answer. content: application/json: schema: type: object description: | The error envelope for every WhatsApp route. Some errors add keys: `fields` (the template parameters a send still needs), `ref` (a 500's support reference) and `failed` (on `import_failed`). properties: error: type: string description: Machine-readable category, such as `invalid_request`. error_description: type: string description: Human-readable explanation. code: type: string description: Stable, specific reason, such as `window_closed`. request_id: type: string description: >- Correlates this response with the server log. Also sent as the `X-Request-Id` header. fields: type: array items: type: string description: >- On a template send missing parameters (`missing_fields`), the field keys you still need. ref: type: string description: On a `500`, the reference to quote to support. failed: type: array items: type: object properties: phone_number_id: type: string message: type: string example: >- This WhatsApp number is already connected to another account. Disconnect it there first, then import it again. Contact support if you cannot access that account. description: On `import_failed`, each number and why it could not be connected. example: error: not_found error_description: WhatsApp number not found. code: number_not_found request_id: req_2c8e7a1d9b40 '409': description: >- `invalid_transition`: the campaign is paused, completed, failed or canceled, and takes no new contacts. content: application/json: schema: type: object description: | The error envelope for every WhatsApp route. Some errors add keys: `fields` (the template parameters a send still needs), `ref` (a 500's support reference) and `failed` (on `import_failed`). properties: error: type: string description: Machine-readable category, such as `invalid_request`. error_description: type: string description: Human-readable explanation. code: type: string description: Stable, specific reason, such as `window_closed`. request_id: type: string description: >- Correlates this response with the server log. Also sent as the `X-Request-Id` header. fields: type: array items: type: string description: >- On a template send missing parameters (`missing_fields`), the field keys you still need. ref: type: string description: On a `500`, the reference to quote to support. failed: type: array items: type: object properties: phone_number_id: type: string message: type: string example: >- This WhatsApp number is already connected to another account. Disconnect it there first, then import it again. Contact support if you cannot access that account. description: On `import_failed`, each number and why it could not be connected. '500': description: Something went wrong on our side. Quote `ref` to support. content: application/json: schema: type: object description: | The error envelope for every WhatsApp route. Some errors add keys: `fields` (the template parameters a send still needs), `ref` (a 500's support reference) and `failed` (on `import_failed`). properties: error: type: string description: Machine-readable category, such as `invalid_request`. error_description: type: string description: Human-readable explanation. code: type: string description: Stable, specific reason, such as `window_closed`. request_id: type: string description: >- Correlates this response with the server log. Also sent as the `X-Request-Id` header. fields: type: array items: type: string description: >- On a template send missing parameters (`missing_fields`), the field keys you still need. ref: type: string description: On a `500`, the reference to quote to support. failed: type: array items: type: object properties: phone_number_id: type: string message: type: string example: >- This WhatsApp number is already connected to another account. Disconnect it there first, then import it again. Contact support if you cannot access that account. description: On `import_failed`, each number and why it could not be connected. example: error: server_error error_description: >- Something went wrong on our side. Please try again shortly, or contact support with reference 9a1f3e8b02c4. ref: 9a1f3e8b02c4 code: server_error request_id: req_9a1f3e8b02c4 ``` **curl** ```bash curl -X POST "https://omnidim.io/api/v1/whatsapp/campaigns/{campaign_id}/contacts" \ -H "Authorization: Bearer $OMNIDIM_API_KEY" \ -H "Content-Type: application/json" \ -d '[ { "phone_number": "+15551234567", "contact_name": "Demo User" }, { "phone_number": "+15557654321", "contact_name": "Second User" } ]' ```