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

# Check RCS reachability

> Checks whether a phone number can receive RCS messages from your RCS sender, without sending anything. Call it before an RCS send to choose between RCS and SMS for that contact.



## OpenAPI

````yaml openapi-sms.yaml GET /messages/rcs-reachability
openapi: 3.0.3
info:
  title: Vobiz Messaging API
  description: >
    Send and receive SMS, MMS and RCS messages, buy messaging numbers, register
    for

    US 10DLC and toll-free, run broadcasts, manage conversations, opt-outs and
    webhooks.


    **Base URL:** `https://api.vobiz.ai/api/v1/sms`


    **Authentication:** every request needs the `X-Auth-ID` and `X-Auth-Token`
    headers.

    The account is taken from your credentials; you never put an account ID in a
    path or body.

    Field names in this API are camelCase.
  version: '1.0'
  contact:
    email: support@vobiz.ai
    url: https://vobiz.ai
servers:
  - url: https://api.vobiz.ai/api/v1/sms
    description: Production
security:
  - AuthID: []
    AuthToken: []
tags:
  - name: Messages
    description: Send messages and inspect their delivery state.
  - name: Numbers
    description: >-
      Messaging-capable numbers on your account, inventory search, purchase and
      release.
  - name: Coverage
    description: Where you can send, per country.
  - name: Conversations
    description: Two-way threads between one of your numbers and a contact.
  - name: Opt-outs
    description: Numbers that must not receive messages on a channel.
  - name: Webhooks
    description: Subscriptions that deliver message and broadcast events to your server.
  - name: Broadcasts
    description: Bulk sends from an uploaded recipient list.
  - name: RCS Senders
    description: RCS sender (agent) identities and their message templates.
  - name: 10DLC Brands
    description: US 10DLC brand registration.
  - name: 10DLC Campaigns
    description: US 10DLC campaigns, toll-free verification and supporting documents.
paths:
  /messages/rcs-reachability:
    get:
      tags:
        - Messages
      summary: Check RCS reachability
      description: >-
        Checks whether a phone number can receive RCS messages from your RCS
        sender, without sending anything. Call it before an RCS send to choose
        between RCS and SMS for that contact. If `reachable` is `false`, send
        with `channel: "sms"` instead, or send RCS with `failoverToSms: true` so
        Vobiz falls back to SMS automatically.
      operationId: check-rcs-reachability
      parameters:
        - name: from
          in: query
          required: true
          description: >-
            Required. The `senderName` of your RCS sender, as returned by `GET
            /senders`.
          schema:
            type: string
          example: YOUR_RCS_SENDER_NAME
        - name: to
          in: query
          required: true
          schema:
            type: string
          example: '+14155550123'
          description: >-
            Required. The recipient number to check, in E.164 format, for
            example `+14155550123`.
      responses:
        '200':
          description: Reachability result.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RCSReachability'
              example:
                to: '+14155550123'
                reachable: true
                carrier: Example Mobile
                capability: reachable
        '400':
          description: '`from` and `to` are required.'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '500':
          $ref: '#/components/responses/ServerError'
      x-codeSamples:
        - lang: typescript
          label: Node SDK
          source: >
            import { VobizClient } from "@vobiz/sdk";


            const client = new VobizClient({ apiKey: "MA_XXXXXXXX", authToken:
            "YOUR_AUTH_TOKEN" });


            await client.sms.messages.checkRcsReachability({
                from: "YOUR_RCS_SENDER_NAME",
                to: "+14155550123"
            })
        - lang: python
          label: Python SDK
          source: |
            from vobiz import Vobiz

            client = Vobiz(api_key="MA_XXXXXXXX", auth_token="YOUR_AUTH_TOKEN")

            client.sms.messages.check_rcs_reachability(
                from_="YOUR_RCS_SENDER_NAME",
                to="+14155550123",
            )
        - lang: go
          label: Go SDK
          source: |
            import (
                "context"

                vobiz "github.com/vobiz-ai/Vobiz-Go-SDK"
                "github.com/vobiz-ai/Vobiz-Go-SDK/client"
                "github.com/vobiz-ai/Vobiz-Go-SDK/option"
                "github.com/vobiz-ai/Vobiz-Go-SDK/sms"
            )

            c := client.NewClient(
                option.WithAPIKey("MA_XXXXXXXX"),
                option.WithAuthToken("YOUR_AUTH_TOKEN"),
            )

            request := &sms.CheckRcsReachabilityRequest{
                    From: "YOUR_RCS_SENDER_NAME",
                    To: "+14155550123",
                }
            c.Sms.Messages.CheckRcsReachability(
                    context.TODO(),
                    request,
                )
        - lang: java
          label: Java SDK
          source: |
            import com.vobiz.api.VobizApiClient;

            VobizApiClient client = VobizApiClient
                .builder()
                .apiKey("MA_XXXXXXXX")
                .authToken("YOUR_AUTH_TOKEN")
                .build();

            client.sms().messages().checkRcsReachability(
                CheckRcsReachabilityRequest
                    .builder()
                    .from("YOUR_RCS_SENDER_NAME")
                    .to("+14155550123")
                    .build()
            );
        - lang: ruby
          label: Ruby SDK
          source: >
            require 'vobiz'


            client = Vobiz::Client.new(api_key: 'MA_XXXXXXXX', auth_token:
            'YOUR_AUTH_TOKEN')


            client.sms.messages.check_rcs_reachability(
              from: "YOUR_RCS_SENDER_NAME",
              to: "+14155550123"
            )
        - lang: csharp
          label: C# SDK
          source: |
            using Vobiz;
            using Vobiz.Sms;

            var client = new VobizApiClient("YOUR_AUTH_TOKEN", "MA_XXXXXXXX");

            await client.Sms.Messages.CheckRcsReachabilityAsync(
                new CheckRcsReachabilityRequest { From = "YOUR_RCS_SENDER_NAME", To = "+14155550123" }
            );
        - lang: php
          label: PHP SDK
          source: >
            <?php


            require 'vendor/autoload.php';


            use Vobiz\VobizClient;


            $client = new VobizClient(apiKey: 'MA_XXXXXXXX', authToken:
            'YOUR_AUTH_TOKEN');


            $client->sms->messages->checkRcsReachability(
                new CheckRcsReachabilityRequest([
                    'from' => 'YOUR_RCS_SENDER_NAME',
                    'to' => '+14155550123',
                ]),
            );
components:
  schemas:
    RCSReachability:
      type: object
      properties:
        to:
          type: string
          example: '+14155550123'
          description: The phone number that was checked, in E.164 format.
        reachable:
          type: boolean
          description: >-
            `true` when the number can receive RCS from your sender. When
            `false`, send as SMS or set `failoverToSms` on an RCS send.
        carrier:
          type: string
          description: >-
            Name of the recipient's mobile carrier. Omitted when it is not
            known.
        capability:
          type: string
          description: >-
            Capability label returned with the result, for example `reachable`.
            Base your decision on `reachable`.
      description: Whether a phone number can receive RCS messages from your RCS sender.
    Error:
      type: object
      description: >-
        The body of every error response: a flat object with one `error` string
        that explains what went wrong. Use the HTTP status code to decide how to
        handle the error, and log `error` for diagnosis.
      required:
        - error
      properties:
        error:
          type: string
          example: 'recipient has opted out: +14155550123'
          description: >-
            Human-readable explanation of the error, for example `phoneNumber is
            required` or `recipient has opted out: +14155550123`. Branch on the
            HTTP status code rather than on this text.
  responses:
    Unauthorized:
      description: Missing or invalid `X-Auth-ID` / `X-Auth-Token`.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error: missing or invalid credentials
    ServerError:
      description: Unexpected error. Retry with the same idempotency key where one applies.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error: internal error
  securitySchemes:
    AuthID:
      type: apiKey
      in: header
      name: X-Auth-ID
      description: Your Vobiz account Auth ID (`MA_XXXXXXXX`).
    AuthToken:
      type: apiKey
      in: header
      name: X-Auth-Token
      description: Your Vobiz account Auth Token.

````

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