> ## Documentation Index
> Fetch the complete documentation index at: https://docs.prelude.so/llms.txt
> Use this file to discover all available pages before exploring further.
# Send a code (V1 API)
> This page presents how to send a code with our Legacy API, V1.
The V1 API is **deprecated**. Starting November 1st 2025, no support will be provided for the V1 API and it will be **removed by April 2026**. No new features nor functionality will be added to the V1 API. Please use the [V2 Verify API](/verify/v2/documentation/introduction) instead. For more information refer to the [V2 Migration Guide](/verify/v2/documentation/v2-migration-guide).
**V2 equivalent:** [Create or retry a verification](/verify/v2/api-reference/create-or-retry-a-verification).
## OpenAPI
````yaml post /authentication
openapi: 3.1.0
info:
title: Ding
version: 1.0.0
description: >-
The OTP API allows you to send authentication codes to your users using
their phone numbers. The V1 API is **deprecated**. Technical support will
end by **October 2025** and will be **removed by April 2026**. No new
features and functionality will be added to the V1 API.
contact:
email: support@prelude.so
servers:
- url: https://api.ding.live/v1
description: The production Ding API server
security:
- APIKey: []
tags:
- name: OTP
description: Send OTP codes to your users using their phone numbers.
- name: Lookup
description: Retrieve up-to-date metadata about a specific phone number
paths:
/authentication:
post:
tags:
- OTP
summary: Send a code
description: Send an OTP code to a user's phone number.
operationId: create-authentication
requestBody:
content:
application/json:
schema:
$ref: '#/components/schemas/CreateAuthenticationRequest'
responses:
'200':
description: OK
content:
application/json:
schema:
$ref: '#/components/schemas/CreateAuthenticationResponse'
'400':
description: Bad Request
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
deprecated: true
components:
schemas:
CreateAuthenticationRequest:
type: object
required:
- customer_uuid
- phone_number
properties:
customer_uuid:
type: string
format: uuid
description: >-
Your customer UUID, which can be found in the API settings in the
dashboard.
phone_number:
type: string
format: phone_number
examples:
- '+1234567890'
description: An E.164 formatted phone number to send the OTP to.
ip:
type: string
format: ipv4
description: The IP address of the user's device.
device_id:
type: string
description: >-
Unique identifier for the user's device. For Android, this
corresponds to the `ANDROID_ID` and for iOS, this corresponds to the
`identifierForVendor`.
device_type:
type: string
enum:
- IOS
- ANDROID
- WEB
description: The type of device the user is using.
app_version:
type: string
description: The version of your application.
sender_id:
type: string
description: The Sender ID to use when sending the message.
callback_url:
type: string
format: url
description: A webhook URL to which delivery statuses will be sent.
app_realm:
type: string
description: >-
The Android SMS Retriever API hash code that identifies your app.
This allows you to automatically retrieve and fill the OTP code on
Android devices.
os_version:
type: string
description: The version of the user's device operating system.
device_model:
type: string
description: The model of the user's device.
is_returning_user:
type: boolean
description: >-
This signal should do more than just confirm if a user is returning
to your app; it should provide a higher level of trust, indicating
that the user is genuine.
template_id:
type: string
description: >-
The template id associated with the message content variant to be
sent.
correlation_id:
type: string
description: >-
A unique, user-defined identifier that will be included in webhook
events
locale:
type: string
format: BCP-47
examples:
- en-US
- el-GR
- fr-FR
description: >-
A BCP-47 locale indicating the language the SMS should be sent to;
if this is not set, the SMS will be sent to the language specified
by the country code of the message. If we don't support the language
set, the message will be sent in US English (en-US).
CreateAuthenticationResponse:
type: object
description: A successful response to an authentication creation request.
properties:
authentication_uuid:
type: string
format: uuid
description: >-
A unique identifier for the authentication that you can use on the
/check and /retry endpoints.
status:
type: string
description: |
The status of the authentication. Possible values are:
* `pending` - The OTP code is being sent.
* `rate_limited` - This user is rate-limited and cannot receive another code.
* `spam_detected` - This attempt is flagged as spam. Go to the dashboard for more details.
enum:
- pending
- rate_limited
- spam_detected
created_at:
type: string
format: date-time
expires_at:
type: string
format: date-time
description: >-
The time at which the authentication expires and can no longer be
checked or retried.
ErrorResponse:
type: object
properties:
code:
type: string
examples:
- invalid_phone_number
description: A machine-readable code that describes the error.
enum:
- account_invalid
- app_realm_require_device_type
- bad_request
- blocked_number
- internal_server_error
- invalid_app_realm
- invalid_app_version
- invalid_auth_uuid
- invalid_device_id
- invalid_device_model
- invalid_line
- invalid_os_version
- invalid_phone_number
- invalid_sender_id
- invalid_template_id
- negative_balance
- no_associated_auth_found
- suspended_account
- unauthorized_sender_id
- unsupported_app_realm_device_type
- unsupported_region
message:
type: string
examples:
- +0 is not a valid phone number
description: A human-readable message that describes the error.
doc_url:
type: string
description: A link to the documentation that describes the error.
examples:
- >-
https://docs.prelude.so/verify/v1/documentation/errors#invalid_phone_number
securitySchemes:
APIKey:
name: x-api-key
type: apiKey
in: header
x-speakeasy-example: YOUR_API_KEY
````