> ## Documentation Index
> Fetch the complete documentation index at: https://docs.smartsend.co.il/llms.txt
> Use this file to discover all available pages before exploring further.

# Set a custom field value on a conversation by phone number

> Sets or clears a value for one of the organization-level custom fields on a conversation. Creates the conversation if it doesn't exist. Identify the field with either `fieldId` (preferred, from `/rpc/custom-fields`) or `fieldName`. Pass `value: null` to clear the field.




## OpenAPI

````yaml /openapi-make.json post /integrations/make/conversations/set-custom-field
openapi: 3.0.3
info:
  title: SmartSend Make.com API
  version: 1.0.0
  description: >-
    Public HTTP API for the SmartSend Make.com integration. Every request is
    authenticated with the `x-organization-id` header. These are the endpoints
    Make.com (and any external automation tool) calls to send messages, manage
    conversations, tags, lists, custom fields, and more.
  contact:
    name: SmartSend Support
    email: support@smartsend.com
servers:
  - url: https://smartsend-server.otherwise.co.il
    description: Production
  - url: http://localhost:3091
    description: Local development
security:
  - organizationId: []
tags: []
paths:
  /integrations/make/conversations/set-custom-field:
    post:
      tags:
        - Make.com Integration
      summary: Set a custom field value on a conversation by phone number
      description: >
        Sets or clears a value for one of the organization-level custom fields
        on a conversation. Creates the conversation if it doesn't exist.
        Identify the field with either `fieldId` (preferred, from
        `/rpc/custom-fields`) or `fieldName`. Pass `value: null` to clear the
        field.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - phoneNumber
              properties:
                phoneNumber:
                  type: string
                  description: Phone number in any format (972..., 05..., +972...)
                fieldId:
                  type: string
                  description: ID of the custom field (from /rpc/custom-fields)
                fieldName:
                  type: string
                  description: Name of the custom field (alternative to fieldId)
                value:
                  type: string
                  nullable: true
                  description: Value to set. Pass null to clear.
      responses:
        '200':
          description: Custom field set successfully
      security:
        - organizationId: []
components:
  securitySchemes:
    organizationId:
      type: apiKey
      in: header
      name: x-organization-id
      description: Your SmartSend Organization ID. Required on every request.

````