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

# Reply to a thread

> Send a reply to a thread. From, from_name, reply_to, to, and subject are auto-resolved from the thread's inbox if not provided.



## OpenAPI

````yaml /openapi.json post /v1/threads/{threadId}/reply
openapi: 3.0.3
info:
  title: Emailr API
  version: 1.0.0
servers:
  - url: https://api.emailr.dev
    description: Production
security: []
tags:
  - name: emails
    description: Email sending and management
  - name: contacts
    description: Contact management
  - name: templates
    description: Email template management
  - name: domains
    description: Domain verification and management
  - name: webhooks
    description: Webhook configuration
  - name: broadcasts
    description: Broadcast campaign management
  - name: segments
    description: Contact segmentation
paths:
  /v1/threads/{threadId}/reply:
    post:
      tags:
        - threads
      summary: Reply to a thread
      description: >-
        Send a reply to a thread. From, from_name, reply_to, to, and subject are
        auto-resolved from the thread's inbox if not provided.
      operationId: replyToThread
      parameters:
        - schema:
            type: string
            format: uuid
          required: true
          name: threadId
          in: path
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ThreadReplyRequest'
      responses:
        '200':
          description: Reply sent
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ThreadReplyResponse'
        '400':
          description: Validation error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          description: Unauthorized
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '404':
          description: Thread not found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      security:
        - bearerAuth: []
components:
  schemas:
    ThreadReplyRequest:
      type: object
      properties:
        html:
          type: string
          example: <p>Thanks for reaching out!</p>
        text:
          type: string
          example: Thanks for reaching out!
        to:
          anyOf:
            - type: string
              format: email
            - type: array
              items:
                type: string
                format: email
          description: >-
            Override recipient. Auto-resolved from last received message if
            omitted.
        cc:
          anyOf:
            - type: string
              format: email
            - type: array
              items:
                type: string
                format: email
        bcc:
          anyOf:
            - type: string
              format: email
            - type: array
              items:
                type: string
                format: email
        from:
          type: string
          description: Override sender. Auto-resolved from thread inbox if omitted.
        from_name:
          type: string
          description: >-
            Override sender display name. Auto-resolved from inbox name if
            omitted.
        reply_to_email:
          type: string
          format: email
          description: >-
            Override Reply-To. Auto-resolved from inbox inbound address if
            omitted.
        attachments:
          type: array
          items:
            type: object
            properties:
              filename:
                type: string
              content:
                type: string
              contentType:
                type: string
            required:
              - filename
              - content
    ThreadReplyResponse:
      type: object
      properties:
        success:
          type: boolean
        message_id:
          type: string
        recipients:
          type: number
        status:
          type: string
      required:
        - success
        - message_id
        - recipients
        - status
    Error:
      type: object
      properties:
        error:
          type: string
          example: An error occurred
        code:
          type: string
          example: VALIDATION_ERROR
        details: {}
      required:
        - error
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: API key authentication. Use your API key as the bearer token.

````