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Authy One-Time Passwords (OTP)

Before sending a One-Time Password:

  1. Create an Authy Application (see Applications documentation)
  2. Create a User (see Users documentation)

Once a user has been registered with your Twilio Authy application and receives an AuthyID, you can now implement 2FA, passwordless login or protect an in-application high-value transaction. Using the Authy API, you can send one-time passwords over voice or SMS channels.

Users can also install the free Authy app or use our SDK to generate offline TOTP codes (soft tokens). Soft tokens do not require wireless connectivity to issue and verify.

The Authy API is used to verify a user has access to the right phone number (for SMS and Voice channels) or has access to the right trusted device (for TOTP via the Authy App or use of the SDK).

Twilio's Authy API follows the algorithms described in RFC 6238 and RFC 4226 to generate TOTP (Time-Based One-Time Passwords) passwords. It is also possible to use your own hardware tokens, please contact us for information on how to enable this type of 2FA.

Request a One-Time Password

When you call the API to start either an SMS or voice-based authentication, it automatically checks to see if that user has previously downloaded the Authy app or has an app installed that uses our SDK. If the user has the Authy App, by default, the API will not send the 2FA code via SMS or voice. Instead, a push notification will go to the device, prompting the user to start their app to get the code.

If a user has no record of installing a device, then the API will continue to send the code via SMS or voice. You can override the default behavior to force the sending of code via SMS or voice every time. This is a useful override if a user is specifically selecting "Send SMS" or "Get code via voice call" in your application UI.

For information on timing and other constraints like rate limiting, see our two-factor authentication best practices.

GET https://api.authy.com/protected/{FORMAT}/sms/{AUTHY_ID}

URL

Name Description
FORMAT
String
The format to expect back from the REST API call. json or xml.
AUTHY_ID
Integer
The Authy ID of the user to send an SMS TOTP. Create an Authy ID by registering a user. Note that password delivery may be upgraded to use the Authy application; see response parameters below.

Parameters

Name Description
force
Boolean (optional)
Default is false. Set to true to send one-time passwords over the SMS channel even if the user has an Authy or SDK enabled app installed. Configure default behavior in the console. (🏢 not PII )
action
String (optional)
The optional action or context we are trying to validate. (🏢 not PII )
action_message
String (optional)
Optional message for the specific action. (🏢 not PII )
locale
String (optional)
The language of the message received by user. If no locale is given, Twilio will try to autodetect it based on the country code. English is used if no locale is autodetected. More details below (🏢 not PII )

Response

Name Description
success
Boolean
Returns true if the request was successful. (🏢 not PII )
message
String
A message indicating what happened with the request. (🏢 not PII )
cellphone
String
The country code and last two digits of phone number used to send the message with the rest obfuscated. (🏢 not PII )
ignored
Boolean
True if we detected an Authy or SDK enabled app installed and we upgraded the OTP delivery channel from 'SMS' to Push Notification. Authy or SDK users are redirected directly to the requested token. (🏢 not PII )
device
String
The type of the last device used by the user. This is only returned when we upgraded delivery from SMS. (🏢 not PII )

Supported Languages

Supported languages are: Afrikaans (af), Arabic (ar), Catalan (ca), Chinese (zh), Chinese (Mandarin) (zh-CN), Chinese (Cantonese) (zh-HK), Croatian (hr), Czech (cs), Danish (da), Dutch (nl), English (en), Finnish (fi), French (fr), German (de), Greek (el), Hebrew (he), Hindi (hi), Hungarian (hu), Indonesian (id), Italian (it), Japanese (ja), Korean (ko), Malay (ms), Norwegian (nb), Polish (pl), Portuguese - Brazil (pt-BR), Portuguese (pt), Romanian (ro), Russian (ru), Spanish (es), Swedish (sv), Tagalog (tl), Thai (th), Turkish (tr), Vietnamese (vi). We support the format country-region as described in IETF's BPC 47. If no region is given (or supported), there will be a default by country.

Send a One-time Password Via SMS

        
        
        
        

        Default Behavior for Users with the Authy App Installed

        If the user has the Authy App, by default, the API will not send the 2FA code via SMS or voice. Instead, a push notification will go to the device, prompting the user to start their app to get the code. The user's notification will look like this:

        Authy push notification - app installed on attempt to send an SMS

        If the user has the Authy app installed the API response will look like this:

        {
            "message":"Ignored: SMS is not needed for smartphones. Pass force=true if you want to actually send it anyway.",
            "cellphone":"+1-XXX-XXX-XX02",
            "device":"android",
            "ignored":true,
            "success":true
        }
        

        Override Default Behavior and Force Sending SMS

        You can override this behavior and force sending an SMS or Voice call. This is a useful override if a user is specifically selecting "Send SMS" or "Get code via voice call" in your application UI.

              
              
              
              

              Custom Actions (Optional)

              Optionally, you can limit a specific token to a single action, for example coupling a one-time password to a specific logon request or transaction. Most implementations will not need this feature.

              You can pass action= and action_message= (optional) to send a code that is only valid for the given action. This is useful if you require codes to perform different actions on your app, for example, you can pass action=login&action_message="Login code" when sending a login code.

              When using this option you must pass the same action when verifying the code.

              • When sending an SMS with custom actions it will always send the SMS even if the user has the Authy app installed. Sending force=true is not necessary.
              • Codes generated through regular sms and the Authy app won't work when sending the custom actions parameters to the verify endpoint.
              • Custom actions is not supported for voice calls.
                    
                    
                    
                    
                    Limit an OTP to a single action

                    Send a One-Time Password via Voice

                    For users that don't own a smartphone or are having trouble with SMS Tokens, Authy allows you to use phone calls instead. Like SMS, by default this call will be ignored if the user is using the Authy Mobile app. You can override the default behavior with the force parameter.

                    GET https://api.authy.com/protected/{FORMAT}/call/{AUTHY_ID}
                    

                    URL

                    Name Description
                    FORMAT
                    String
                    The format to expect back from the REST API call. json or xml.
                    AUTHY_ID
                    Integer
                    The Authy ID of the user to send an SMS TOTP. Create an Authy ID by registering a user. Note that password delivery may be upgraded to use the Authy application; see response parameters below.

                    Parameters

                    Name Description
                    force
                    Boolean (optional)
                    Default is false. Set to true to send one-time passwords over the Voice channel even if the user has an Authy or SDK enabled app installed. Configure default behavior in the console. (🏢 not PII )
                    action
                    String (optional)
                    The action or context we are trying to validate. (🏢 not PII )
                    action_message
                    String (optional)
                    Message for the specific action. (🏢 not PII )
                    locale
                    String (optional)
                    The language of the message received by user. If no locale is given, Twilio will try to autodetect it based on the country code. English is used if no locale is autodetected. More details above. (🏢 not PII )

                    Response

                    Name Description
                    success
                    Boolean
                    Returns true if the request was successful. (🏢 not PII )
                    message
                    String
                    A message indicating what happened with the request. (🏢 not PII )
                    cellphone
                    String
                    The country code and last two digits of phone number used to send the message, with the rest obfuscated. (🏢 not PII )
                    ignored
                    Boolean
                    True if we detected an Authy or an SDK enabled app installed and we upgraded the OTP delivery channel from 'Voice' to Push Notification. Authy or SDK users are redirected directly to the requested token. (🏢 not PII )
                    device
                    String
                    The type of the last device used by the user. This is only returned when we upgraded delivery from a voice call. (🏢 not PII )
                          
                          
                          
                          

                          Default Behavior for Users with the Authy App Installed

                          If the user has the Authy App, by default, the API will not call the user. See above for more details. The API response will look like this:

                          {
                            "message": "Call ignored. User is using  App Tokens and this call is not necessary. Pass force=true if you still want to call users that are using the App.",
                            "cellphone": "+1-XXX-XXX-XX02",
                            "device": "android",
                            "ignored": true,
                            "success": true
                          }
                          

                          Like SMS, you can pass force=true as a parameter to this API. This will force the phone call to start even if the user is using the Authy app.

                          Verify a One-Time Password

                          To verify a one-time password pass in the user provided token and the user authy_id. Twilio will use HTTP status codes for the response.

                          GET https://api.authy.com/protected/{FORMAT}/verify/{TOKEN}/{AUTHY_ID}
                          

                          URL

                          Name Description
                          FORMAT
                          String
                          The format to expect back from the REST API call. json, or xml.
                          TOKEN
                          Integer
                          The token you are verifying.
                          AUTHY_ID
                          String
                          The Authy ID of the user validating the TOTP. Create an Authy ID by registering a user.

                          Responses

                          Name Description
                          200 Valid token (see note below)*
                          401 Invalid token. If you wish to verify the token anyway, pass force=true. See the force verification section below for an example.

                          *Note: Until you successfully verify a token for a new user, this call will return 200.

                          Response

                          Name Description
                          token
                          String
                          Either "is valid" or "is invalid" (🏢 not PII )
                          success
                          String
                          "true" if the code was valid. Please note this field is a String and not a Boolean. (🏢 not PII )
                          device
                          Object
                          An object including some details about the device used to get or generate the token. The fields included in the device object are: city, region, country, ip, registration_city, registration_region, registration_country, registration_ip, registration_date, os_type, last_account_recovery_at and id. (📇 PII )

                          When the TOTP token is generated in the Authy app or in the SDK, additional device information and registration data are provided in the response.

                                
                                
                                
                                

                                The same API is used to verify tokens from TOTP, sms, and voice channels. However when the OTP token is delivered via SMS or voice call, no additional device details are provided and the response will look like:

                                {
                                  "message": "Token is valid.",
                                  "token": "is valid",
                                  "success": "true",
                                  "device": {
                                    "id": null,
                                    "os_type": "sms",
                                    "registration_date": 1490996931,
                                    "registration_method": null,
                                    "registration_country": null,
                                    "registration_region": null,
                                    "registration_city": null,
                                    "country": null,
                                    "region": null,
                                    "city": null,
                                    "ip": null,
                                    "last_account_recovery_at": null,
                                    "last_sync_date": null
                                  }
                                }
                                

                                Force One-Time Password Validation for Unregistered User

                                Use force=true to force verification of a one-time password from a new user.

                                curl -i "http://api.authy.com/protected/json/verify/{TOKEN}/{AUTHY_ID}" \
                                  -H "X-Authy-API-Key: d57d919d11e6b221c9bf6f7c882028f9"
                                

                                Response if force=false or Not Set

                                {
                                  "token":"Not checked. User has not yet finished the registration process. Pass force=true to this API to check regardless (more secure)."
                                }
                                

                                Response if force=true

                                {
                                  "errors": {
                                    "token":"is invalid"
                                  }
                                }
                                

                                Verify Tokens when using Authy Custom Actions

                                When using custom actions to send SMS you have to pass action= to validate the one-time password.
                                For more information see Custom Actions.

                                {
                                  "token": "is valid"
                                }
                                

                                Invalid Tokens

                                A verification attempt with an invalid token will return a 401 Unauthorized with the following Response body:

                                {
                                  "message": "Token is invalid",
                                  "token": "is invalid",
                                  "success": false,
                                  "errors": {
                                    "message": "Token is invalid"
                                  },
                                  "error_code": "60020"
                                }
                                

                                Authenticator App Generated Time-based One-Time Passwords

                                Authy App

                                When you enroll a user, they will automatically be able to generate Soft Token TOTP codes in the Authy App if they register for Authy with the same phone number that you used to enroll them. You do not need to do anything additional to take advantage of the Authy app. You can disable this behavior with the 'Sync tokens in Authy app' setting in the Authy settings in the Twilio Console.

                                To validate these One-Time Passwords, see Verify a One-Time Password below.

                                Authenticator SDK

                                You can embed the same functionality from the Authy app into any mobile application using the Twilio Authenticator SDK.

                                Other Authenticator Apps

                                In order to support other Authenticator apps, like Google Authenticator, you will need to display a QR code to your users that contain a compatible OTP secret. The API will return a link to a valid QR code.

                                In order to customize the QR label and give the final user context about the token like account name or email, you can include the label param in the QR generation endpoint. That way many Authenticator apps will automatically render the label in the token list.

                                To enable, browse to your Authy application in the Twilio Console. Click on your App's Settings and scroll to the bottom.

                                Note, each QR code request will generate a unique TOTP seed. As such, you can only have a single active QR code per user per protected site. Requesting an additional QR code for a user will invalidate the previous secret and generate a new QR code.

                                When providing a QR code to a user, be sure to have them validate the code before applying 2FA protection to their account.

                                POST https://api.authy.com/protected/{FORMAT}/users/{AUTHY_ID}/secret
                                

                                URL

                                Name Description
                                FORMAT
                                String
                                The format to expect back from the REST API call. json or xml.
                                AUTHY_ID
                                Integer
                                The Authy ID of the user to send an SMS TOTP. Create an Authy ID by registering a user.

                                Parameters

                                Name Description
                                qr_size
                                Integer (optional)
                                Dimension of the QR code that will be returned. Square, so only one number required. Default value is 256. Max value is 320. (🏢 not PII )
                                label
                                String (optional)
                                A custom label for the QR code, this field will be shown by the Authenticator app, it gives context to the user, like the account email. Default value is the application name. (📇 PII )
                                      
                                      
                                      
                                      
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