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

# Reply to an inbox message

> Sends from the inbox address through the standard email send pipeline. The recipient is
the original `Reply-To`, falling back to `From`; original Cc recipients are not included.
The subject is prefixed with `Re:` unless it already has that prefix.

Threading headers are derived from the original message: `In-Reply-To` is set to its
RFC Message-ID, and `References` contains the original References values plus that
Message-ID, de-duplicated and limited to the most recent 20 values.




## OpenAPI

````yaml /openapi/generated/email/inboxes.yml post /email_inboxes/{inbox_id}/messages/{message_id}/actions/reply
openapi: 3.1.0
info:
  contact:
    email: support@telnyx.com
  description: API for managing email inboxes, drafts, messages, filters, and threads.
  title: Telnyx Email Inboxes API
  version: 2.0.0
servers:
  - url: https://api.telnyx.com/v2
security:
  - bearerAuth: []
paths:
  /email_inboxes/{inbox_id}/messages/{message_id}/actions/reply:
    post:
      tags:
        - Email Inboxes
      summary: Reply to an inbox message
      description: >
        Sends from the inbox address through the standard email send pipeline.
        The recipient is

        the original `Reply-To`, falling back to `From`; original Cc recipients
        are not included.

        The subject is prefixed with `Re:` unless it already has that prefix.


        Threading headers are derived from the original message: `In-Reply-To`
        is set to its

        RFC Message-ID, and `References` contains the original References values
        plus that

        Message-ID, de-duplicated and limited to the most recent 20 values.
      operationId: ReplyToEmailInboxMessage
      parameters:
        - name: inbox_id
          in: path
          required: true
          description: Email inbox UUID.
          schema:
            type: string
            format: uuid
        - name: message_id
          in: path
          required: true
          description: Inbound email message UUID.
          schema:
            type: string
            format: uuid
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ReplyEmailInboxMessageRequest'
            examples:
              plainText:
                value:
                  text: Thanks for the update.
              html:
                value:
                  html: <p>Thanks for the update.</p>
      responses:
        '202':
          description: Reply accepted by the standard email send pipeline.
          headers:
            X-Telnyx-Reputation-Warning:
              description: >-
                Present with `warn` when the accepted send uses a sender domain
                in the reputation warn band; delivery proceeds with reduced
                sending limits.
              schema:
                type: string
                enum:
                  - warn
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/EmailMessageResponse'
              example:
                data:
                  record_type: email_message
                  id: 44444444-4444-4444-4444-444444444444
                  status: queued
                  from:
                    email: agent@inbox.example.test
                  to:
                    - email: reply@example.com
                  cc: []
                  bcc: []
                  reply_to: null
                  subject: 'Re: Project update'
                  template_id: null
                  template_variables: {}
                  attachments: []
                  events: []
                  created_at: '2026-07-15T12:35:00Z'
        '400':
          $ref: '#/components/responses/email_BadRequestResponse'
        '401':
          $ref: '#/components/responses/email_UnauthorizedResponse'
        '403':
          $ref: '#/components/responses/email_ForbiddenResponse'
        '404':
          description: The inbox, source message, or sending domain was not found (10001).
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/email_ErrorResponse'
              examples:
                inboxNotFound:
                  value:
                    errors:
                      - code: '10001'
                        title: Not Found
                        detail: The requested email_inbox was not found
                messageNotFound:
                  value:
                    errors:
                      - code: '10001'
                        title: Not Found
                        detail: The requested email_message was not found
        '422':
          description: Reply validation failed (10015), or all recipients are suppressed.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/email_ErrorResponse'
              example:
                errors:
                  - code: '10015'
                    title: Validation Failed
                    detail: text or html must contain a body for reply actions
                    source:
                      pointer: /data/attributes/text
        '429':
          description: Sending is suspended because the inbox domain reputation is too low.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/email_ErrorResponse'
              example:
                errors:
                  - code: reputation_suspended
                    title: Sending Suspended
                    detail: >-
                      Sender domain reputation is too low. Sending has been
                      suspended. Please contact support to resolve
                      deliverability issues.
        '503':
          description: >-
            Inbox message actions or the email domain service are temporarily
            unavailable (10016).
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/email_ErrorResponse'
              example:
                errors:
                  - code: '10016'
                    title: Service Unavailable
                    detail: >-
                      Inbox message actions are temporarily unavailable. Please
                      try again later.
      x-codeSamples:
        - lang: JavaScript
          source: >-
            import Telnyx from 'telnyx';


            const client = new Telnyx({
              apiKey: process.env['TELNYX_API_KEY'], // This is the default and can be omitted
            });


            const response = await
            client.emailInboxes.messages.actions.reply('inbox_id', 'message_id',
            {
              text: 'text',
            });


            console.log(response.data);
        - lang: Python
          source: |-
            import os
            from telnyx import Telnyx

            client = Telnyx(
                api_key=os.environ.get("TELNYX_API_KEY"),  # This is the default and can be omitted
            )
            response = client.email_inboxes.messages.actions.reply(
                inbox_id="inbox_id",
                message_id="message_id",
                text="text",
            )
            print(response.data)
        - lang: Go
          source: "package main\n\nimport (\n\t\"context\"\n\t\"fmt\"\n\n\t\"github.com/team-telnyx/telnyx-go\"\n\t\"github.com/team-telnyx/telnyx-go/option\"\n)\n\nfunc main() {\n\tclient := telnyx.NewClient(\n\t\toption.WithAPIKey(\"My API Key\"),\n\t)\n\tresponse, err := client.EmailInboxes.Messages.Actions.Reply(\n\t\tcontext.TODO(),\n\t\t\"inbox_id\",\n\t\t\"message_id\",\n\t\ttelnyx.EmailInboxeMessageActionReplyParams{\n\t\t\tText: telnyx.String(\"text\"),\n\t\t},\n\t)\n\tif err != nil {\n\t\tpanic(err.Error())\n\t}\n\tfmt.Printf(\"%+v\\n\", response.Data)\n}\n"
        - lang: Java
          source: >-
            package com.telnyx.sdk.example;


            import com.telnyx.sdk.client.TelnyxClient;

            import com.telnyx.sdk.client.okhttp.TelnyxOkHttpClient;

            import
            com.telnyx.sdk.models.emailInboxes.messages.actions.ActionReplyParams;


            public final class Main {
                private Main() {}

                public static void main(String[] args) {
                    TelnyxClient client = TelnyxOkHttpClient.fromEnv();

                    ActionReplyParams params = ActionReplyParams.builder()
                        .text("text")
                        .build();
                    var response = client.emailInboxes().messages().actions().reply("inbox_id", "message_id", params);
                }
            }
        - lang: Ruby
          source: >-
            require "telnyx"


            telnyx = Telnyx::Client.new(api_key: "My API Key")


            response = telnyx.email_inboxes.messages.actions.reply("inbox_id",
            "message_id", text: "text")


            puts(response)
        - lang: PHP
          source: >-
            <?php


            require_once dirname(__DIR__) . '/vendor/autoload.php';


            use Telnyx\Client;

            use Telnyx\Core\Exceptions\APIException;


            $client = new Client(apiKey: getenv('TELNYX_API_KEY') ?: 'My API
            Key');


            try {
              $response = $client->emailInboxes->messages->actions->reply(
                'inbox_id',
                'message_id',
                text: 'text',
              );

              var_dump($response);
            } catch (APIException $e) {
              echo $e->getMessage();
            }
        - lang: CLI
          source: |-
            telnyx email-inboxes:messages:actions reply \
              --api-key 'My API Key' \
              --inbox-id inbox_id \
              --message-id message_id \
              --text text
components:
  schemas:
    ReplyEmailInboxMessageRequest:
      type: object
      description: >-
        At least one of `text` or `html` must contain a non-whitespace body.
        Recipients are derived from the source message; caller-supplied `to`,
        `cc`, or `bcc` values are ignored.
      properties:
        text:
          type: string
          minLength: 1
          pattern: \S
          description: Plain-text reply body.
        html:
          type: string
          minLength: 1
          pattern: \S
          description: HTML reply body.
      anyOf:
        - required:
            - text
        - required:
            - html
    EmailMessageResponse:
      type: object
      properties:
        data:
          $ref: '#/components/schemas/EmailMessage'
        suppressed:
          type: array
          description: >-
            Recipients removed by suppression checks when at least one recipient
            remains and the message is accepted.
          items:
            $ref: '#/components/schemas/SuppressedRecipient'
      required:
        - data
    email_ErrorResponse:
      type: object
      properties:
        errors:
          type: array
          items:
            $ref: '#/components/schemas/ErrorObject'
        suppressed:
          type: array
          description: >-
            Present when every recipient is suppressed, so the request is
            rejected and no message is created.
          items:
            $ref: '#/components/schemas/SuppressedRecipient'
      required:
        - errors
    EmailMessage:
      type: object
      properties:
        record_type:
          type: string
          enum:
            - email_message
        id:
          type: string
          format: uuid
        status:
          $ref: '#/components/schemas/EmailMessageStatus'
        from:
          $ref: '#/components/schemas/EmailAddress'
        to:
          type: array
          items:
            $ref: '#/components/schemas/EmailAddress'
        cc:
          type: array
          items:
            $ref: '#/components/schemas/EmailAddress'
        bcc:
          type: array
          items:
            $ref: '#/components/schemas/EmailAddress'
        reply_to:
          type:
            - string
            - 'null'
        subject:
          type: string
        template_id:
          type:
            - string
            - 'null'
          format: uuid
        template_variables:
          type: object
          additionalProperties: true
          default: {}
        attachments:
          type: array
          items:
            $ref: '#/components/schemas/AttachmentResponse'
        events:
          type: array
          items:
            $ref: '#/components/schemas/MessageEvent'
        created_at:
          type: string
          format: date-time
        scheduled_at:
          type: string
          format: date-time
          description: >-
            Present when a scheduled_at value was stored. Persists even after
            the scheduled send has been processed or cancelled.
        inline_css:
          type: boolean
          description: >-
            Present when true in the immediate create response. Not persisted;
            absent on subsequent GET requests.
        sandbox:
          type: boolean
          description: Present when sandbox mode was used.
        recipient_statuses:
          type: object
          description: >
            Per-status recipient counts for the message. Present only for
            outbound messages

            with recipient rows. Keys are recipient statuses, values are counts.

            Example: `{"delivered": 998, "bounced": 2}`.
          additionalProperties:
            type: integer
          example:
            delivered: 998
            bounced: 2
      required:
        - record_type
        - id
        - status
        - from
        - to
        - cc
        - bcc
        - subject
        - reply_to
        - template_id
        - template_variables
        - attachments
        - events
        - created_at
    SuppressedRecipient:
      type: object
      properties:
        to:
          type: string
          format: email
          description: Suppressed recipient email address.
        reason:
          type: string
          description: Suppression reason returned by the recipient suppression service.
        scope:
          type: string
          description: Scope at which the suppression applies.
        override_allowed:
          type: boolean
          description: Whether an authorized send may override this suppression.
      required:
        - to
        - reason
        - scope
        - override_allowed
    ErrorObject:
      type: object
      properties:
        code:
          type: string
          description: >-
            Telnyx error code. Edge idempotency errors use 10027 or 10036.
            Fallback 404/500 responses from the framework may use string status
            codes ('404', '500') instead.
          enum:
            - '10001'
            - '10006'
            - '10007'
            - '10015'
            - '10016'
            - '10019'
            - recipient_suppressed
            - reputation_suspended
            - '404'
            - '500'
            - '10027'
            - '10036'
        title:
          type: string
        detail:
          description: >-
            Human-readable error detail. Changeset responses may return a
            structured object.
          oneOf:
            - type: string
            - type: object
              additionalProperties: true
        source:
          type:
            - object
            - 'null'
          additionalProperties: true
        meta:
          type:
            - object
            - 'null'
          additionalProperties: true
          description: Additional metadata. Present on 401 errors with a documentation URL.
      required:
        - code
        - title
        - detail
    EmailMessageStatus:
      type: string
      description: >-
        Current status of an email message. Lifecycle statuses (queued,
        scheduled, etc.) are set on creation. Delivery statuses (delivered,
        bounced, etc.) are updated by delivery event consumers.
      enum:
        - queued
        - scheduled
        - cancelled
        - sandbox
        - sending
        - sent
        - failed
        - deferred
        - delivered
        - bounced
        - complained
        - rejected
        - opened
        - clicked
        - unsubscribed
    EmailAddress:
      type: object
      properties:
        email:
          type: string
        name:
          type: string
      required:
        - email
    AttachmentResponse:
      type: object
      description: EDR-aligned attachment metadata. The base64 `content` is never returned.
      properties:
        url:
          type:
            - string
            - 'null'
          format: uri
          description: Telnyx-hosted public URL for the attachment content.
        sha256:
          type:
            - string
            - 'null'
          description: SHA-256 hex digest of the attachment content.
        size_bytes:
          type:
            - integer
            - 'null'
          description: Attachment size in bytes.
        filename:
          type: string
        content_type:
          type: string
        disposition:
          type: string
          default: attachment
          description: >-
            MIME disposition (e.g. `attachment` or `inline`). Runtime passes
            through the stored value without enforcing an enum.
        content_id:
          type:
            - string
            - 'null'
          description: MIME Content-ID for inline references.
      required:
        - url
        - sha256
        - size_bytes
        - filename
        - content_type
        - disposition
        - content_id
    MessageEvent:
      type: object
      properties:
        type:
          $ref: '#/components/schemas/EmailEventType'
        occurred_at:
          type: string
          format: date-time
        payload:
          type: object
          additionalProperties: true
      required:
        - type
        - occurred_at
    EmailEventType:
      type: string
      enum:
        - queued
        - deferred
        - scheduled
        - cancelled
        - sandbox
        - sending
        - sent
        - failed
        - delivered
        - bounced
        - complained
        - rejected
        - opened
        - clicked
        - unsubscribed
        - daily_limit_exceeded
  responses:
    email_BadRequestResponse:
      description: Bad Request / Validation Failed (10015).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/email_ErrorResponse'
          example:
            errors:
              - code: '10015'
                title: Bad Request
                detail: email is required
    email_UnauthorizedResponse:
      description: Not authorized (10006).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/email_ErrorResponse'
          example:
            errors:
              - code: '10006'
                title: Not authorized
                detail: Invalid API key
                meta:
                  url: https://developers.telnyx.com/docs/overview/errors/10006
    email_ForbiddenResponse:
      description: >-
        Forbidden (10007), such as domain not verified, suspended, degraded, or
        missing DKIM.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/email_ErrorResponse'
          example:
            errors:
              - code: '10007'
                title: Forbidden
                detail: >-
                  Domain is not verified. Complete DNS setup before sending
                  email.
  securitySchemes:
    bearerAuth:
      scheme: bearer
      type: http

````