Embedded Passwordless Login in Native Applications

To use the Embedded Passwordless APIs in Native applications, make sure you enable the Passwordless OTP grant at Auth0 Dashboard > Applications > Applications in your application’s settings under Advanced Settings > Grant Types.

Passwordless authentication for Native applications consists of two steps:

• Capture the user identifier in your application (the user’s email or phone number) and invoke the /passwordless/start endpoint to initiate the passwordless flow. The user will get an email or an SMS with a one-time password.
• Prompt the user for the one-time-use code, and call the /oauth/token endpoint to get authentication tokens.

Below we list a few code snippets that can be used to call these API endpoints for different scenarios.

Send a one-time-use password via email

cURL

curl --request POST \
  --url 'https://{yourDomain}/passwordless/start' \
  --header 'content-type: application/json' \
  --data '{"client_id": "{yourClientId}",  "connection": "email",   "email": "USER_EMAIL",  "send": "code"}'

var client = new RestClient("https://{yourDomain}/passwordless/start");
var request = new RestRequest(Method.POST);
request.AddHeader("content-type", "application/json");
request.AddParameter("application/json", "{\"client_id\": \"{yourClientId}\",  \"connection\": \"email\",   \"email\": \"USER_EMAIL\",  \"send\": \"code\"}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://{yourDomain}/passwordless/start"

	payload := strings.NewReader("{\"client_id\": \"{yourClientId}\",  \"connection\": \"email\",   \"email\": \"USER_EMAIL\",  \"send\": \"code\"}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("content-type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://{yourDomain}/passwordless/start")
  .header("content-type", "application/json")
  .body("{\"client_id\": \"{yourClientId}\",  \"connection\": \"email\",   \"email\": \"USER_EMAIL\",  \"send\": \"code\"}")
  .asString();

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://{yourDomain}/passwordless/start',
  headers: {'content-type': 'application/json'},
  data: {
    client_id: '{yourClientId}',
    connection: 'email',
    email: 'USER_EMAIL',
    send: 'code'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

#import <Foundation/Foundation.h>

NSDictionary *headers = @{ @"content-type": @"application/json" };
NSDictionary *parameters = @{ @"client_id": @"{yourClientId}",
                              @"connection": @"email",
                              @"email": @"USER_EMAIL",
                              @"send": @"code" };

NSData *postData = [NSJSONSerialization dataWithJSONObject:parameters options:0 error:nil];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://{yourDomain}/passwordless/start"]
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:10.0];
[request setHTTPMethod:@"POST"];
[request setAllHTTPHeaderFields:headers];
[request setHTTPBody:postData];

NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                if (error) {
                                                    NSLog(@"%@", error);
                                                } else {
                                                    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
                                                    NSLog(@"%@", httpResponse);
                                                }
                                            }];
[dataTask resume];

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{yourDomain}/passwordless/start",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{\"client_id\": \"{yourClientId}\",  \"connection\": \"email\",   \"email\": \"USER_EMAIL\",  \"send\": \"code\"}",
  CURLOPT_HTTPHEADER => [
    "content-type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

import http.client

conn = http.client.HTTPSConnection("")

payload = "{\"client_id\": \"{yourClientId}\",  \"connection\": \"email\",   \"email\": \"USER_EMAIL\",  \"send\": \"code\"}"

headers = { 'content-type': "application/json" }

conn.request("POST", "/{yourDomain}/passwordless/start", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

require 'uri'
require 'net/http'
require 'openssl'

url = URI("https://{yourDomain}/passwordless/start")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

request = Net::HTTP::Post.new(url)
request["content-type"] = 'application/json'
request.body = "{\"client_id\": \"{yourClientId}\",  \"connection\": \"email\",   \"email\": \"USER_EMAIL\",  \"send\": \"code\"}"

response = http.request(request)
puts response.read_body

import Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "client_id": "{yourClientId}",
  "connection": "email",
  "email": "USER_EMAIL",
  "send": "code"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://{yourDomain}/passwordless/start")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()

Send a magic link via email

cURL

curl --request POST \
  --url 'https://{yourDomain}/passwordless/start' \
  --header 'content-type: application/json' \
  --data '{ "client_id": "{yourClientId}", "connection": "email", "email": "USER_EMAIL", "send": "link"}'

var client = new RestClient("https://{yourDomain}/passwordless/start");
var request = new RestRequest(Method.POST);
request.AddHeader("content-type", "application/json");
request.AddParameter("application/json", "{ \"client_id\": \"{yourClientId}\", \"connection\": \"email\", \"email\": \"USER_EMAIL\", \"send\": \"link\"}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://{yourDomain}/passwordless/start"

	payload := strings.NewReader("{ \"client_id\": \"{yourClientId}\", \"connection\": \"email\", \"email\": \"USER_EMAIL\", \"send\": \"link\"}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("content-type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://{yourDomain}/passwordless/start")
  .header("content-type", "application/json")
  .body("{ \"client_id\": \"{yourClientId}\", \"connection\": \"email\", \"email\": \"USER_EMAIL\", \"send\": \"link\"}")
  .asString();

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://{yourDomain}/passwordless/start',
  headers: {'content-type': 'application/json'},
  data: {
    client_id: '{yourClientId}',
    connection: 'email',
    email: 'USER_EMAIL',
    send: 'link'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

#import <Foundation/Foundation.h>

NSDictionary *headers = @{ @"content-type": @"application/json" };
NSDictionary *parameters = @{ @"client_id": @"{yourClientId}",
                              @"connection": @"email",
                              @"email": @"USER_EMAIL",
                              @"send": @"link" };

NSData *postData = [NSJSONSerialization dataWithJSONObject:parameters options:0 error:nil];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://{yourDomain}/passwordless/start"]
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:10.0];
[request setHTTPMethod:@"POST"];
[request setAllHTTPHeaderFields:headers];
[request setHTTPBody:postData];

NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                if (error) {
                                                    NSLog(@"%@", error);
                                                } else {
                                                    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
                                                    NSLog(@"%@", httpResponse);
                                                }
                                            }];
[dataTask resume];

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{yourDomain}/passwordless/start",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{ \"client_id\": \"{yourClientId}\", \"connection\": \"email\", \"email\": \"USER_EMAIL\", \"send\": \"link\"}",
  CURLOPT_HTTPHEADER => [
    "content-type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

import http.client

conn = http.client.HTTPSConnection("")

payload = "{ \"client_id\": \"{yourClientId}\", \"connection\": \"email\", \"email\": \"USER_EMAIL\", \"send\": \"link\"}"

headers = { 'content-type': "application/json" }

conn.request("POST", "/{yourDomain}/passwordless/start", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

require 'uri'
require 'net/http'
require 'openssl'

url = URI("https://{yourDomain}/passwordless/start")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

request = Net::HTTP::Post.new(url)
request["content-type"] = 'application/json'
request.body = "{ \"client_id\": \"{yourClientId}\", \"connection\": \"email\", \"email\": \"USER_EMAIL\", \"send\": \"link\"}"

response = http.request(request)
puts response.read_body

import Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "client_id": "{yourClientId}",
  "connection": "email",
  "email": "USER_EMAIL",
  "send": "link"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://{yourDomain}/passwordless/start")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()

Send a one-time-use password via SMS

cURL

curl --request POST \
  --url 'https://{yourDomain}/passwordless/start' \
  --header 'content-type: application/json' \
  --data '{ "client_id": "{yourClientId}",  "connection": "sms",  "phone_number": "USER_PHONE_NUMBER", "send": "code"}'

var client = new RestClient("https://{yourDomain}/passwordless/start");
var request = new RestRequest(Method.POST);
request.AddHeader("content-type", "application/json");
request.AddParameter("application/json", "{ \"client_id\": \"{yourClientId}\",  \"connection\": \"sms\",  \"phone_number\": \"USER_PHONE_NUMBER\", \"send\": \"code\"}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://{yourDomain}/passwordless/start"

	payload := strings.NewReader("{ \"client_id\": \"{yourClientId}\",  \"connection\": \"sms\",  \"phone_number\": \"USER_PHONE_NUMBER\", \"send\": \"code\"}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("content-type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://{yourDomain}/passwordless/start")
  .header("content-type", "application/json")
  .body("{ \"client_id\": \"{yourClientId}\",  \"connection\": \"sms\",  \"phone_number\": \"USER_PHONE_NUMBER\", \"send\": \"code\"}")
  .asString();

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://{yourDomain}/passwordless/start',
  headers: {'content-type': 'application/json'},
  data: {
    client_id: '{yourClientId}',
    connection: 'sms',
    phone_number: 'USER_PHONE_NUMBER',
    send: 'code'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

#import <Foundation/Foundation.h>

NSDictionary *headers = @{ @"content-type": @"application/json" };
NSDictionary *parameters = @{ @"client_id": @"{yourClientId}",
                              @"connection": @"sms",
                              @"phone_number": @"USER_PHONE_NUMBER",
                              @"send": @"code" };

NSData *postData = [NSJSONSerialization dataWithJSONObject:parameters options:0 error:nil];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://{yourDomain}/passwordless/start"]
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:10.0];
[request setHTTPMethod:@"POST"];
[request setAllHTTPHeaderFields:headers];
[request setHTTPBody:postData];

NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                if (error) {
                                                    NSLog(@"%@", error);
                                                } else {
                                                    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
                                                    NSLog(@"%@", httpResponse);
                                                }
                                            }];
[dataTask resume];

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{yourDomain}/passwordless/start",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{ \"client_id\": \"{yourClientId}\",  \"connection\": \"sms\",  \"phone_number\": \"USER_PHONE_NUMBER\", \"send\": \"code\"}",
  CURLOPT_HTTPHEADER => [
    "content-type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

import http.client

conn = http.client.HTTPSConnection("")

payload = "{ \"client_id\": \"{yourClientId}\",  \"connection\": \"sms\",  \"phone_number\": \"USER_PHONE_NUMBER\", \"send\": \"code\"}"

headers = { 'content-type': "application/json" }

conn.request("POST", "/{yourDomain}/passwordless/start", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

require 'uri'
require 'net/http'
require 'openssl'

url = URI("https://{yourDomain}/passwordless/start")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

request = Net::HTTP::Post.new(url)
request["content-type"] = 'application/json'
request.body = "{ \"client_id\": \"{yourClientId}\",  \"connection\": \"sms\",  \"phone_number\": \"USER_PHONE_NUMBER\", \"send\": \"code\"}"

response = http.request(request)
puts response.read_body

import Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "client_id": "{yourClientId}",
  "connection": "sms",
  "phone_number": "USER_PHONE_NUMBER",
  "send": "code"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://{yourDomain}/passwordless/start")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()

Authenticate an SMS user

cURL

curl --request POST \
  --url 'https://{yourDomain}/oauth/token' \
  --header 'content-type: application/json' \
  --data '{ "grant_type": "http://auth0.com/oauth/grant-type/passwordless/otp",  "client_id": "{yourClientId}",  "username": "USER_PHONE_NUMBER",  "otp": "code",  "realm": "sms", "audience": "your-api-audience", "scope": "openid profile email"}'

var client = new RestClient("https://{yourDomain}/oauth/token");
var request = new RestRequest(Method.POST);
request.AddHeader("content-type", "application/json");
request.AddParameter("application/json", "{ \"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\",  \"client_id\": \"{yourClientId}\",  \"username\": \"USER_PHONE_NUMBER\",  \"otp\": \"code\",  \"realm\": \"sms\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://{yourDomain}/oauth/token"

	payload := strings.NewReader("{ \"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\",  \"client_id\": \"{yourClientId}\",  \"username\": \"USER_PHONE_NUMBER\",  \"otp\": \"code\",  \"realm\": \"sms\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("content-type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://{yourDomain}/oauth/token',
  headers: {'content-type': 'application/json'},
  data: {
    grant_type: 'http://auth0.com/oauth/grant-type/passwordless/otp',
    client_id: '{yourClientId}',
    username: 'USER_PHONE_NUMBER',
    otp: 'code',
    realm: 'sms',
    audience: 'your-api-audience',
    scope: 'openid profile email'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

#import <Foundation/Foundation.h>

NSDictionary *headers = @{ @"content-type": @"application/json" };
NSDictionary *parameters = @{ @"grant_type": @"http://auth0.com/oauth/grant-type/passwordless/otp",
                              @"client_id": @"{yourClientId}",
                              @"username": @"USER_PHONE_NUMBER",
                              @"otp": @"code",
                              @"realm": @"sms",
                              @"audience": @"your-api-audience",
                              @"scope": @"openid profile email" };

NSData *postData = [NSJSONSerialization dataWithJSONObject:parameters options:0 error:nil];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://{yourDomain}/oauth/token"]
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:10.0];
[request setHTTPMethod:@"POST"];
[request setAllHTTPHeaderFields:headers];
[request setHTTPBody:postData];

NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                if (error) {
                                                    NSLog(@"%@", error);
                                                } else {
                                                    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
                                                    NSLog(@"%@", httpResponse);
                                                }
                                            }];
[dataTask resume];

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{yourDomain}/oauth/token",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{ \"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\",  \"client_id\": \"{yourClientId}\",  \"username\": \"USER_PHONE_NUMBER\",  \"otp\": \"code\",  \"realm\": \"sms\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}",
  CURLOPT_HTTPHEADER => [
    "content-type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

import http.client

conn = http.client.HTTPSConnection("")

payload = "{ \"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\",  \"client_id\": \"{yourClientId}\",  \"username\": \"USER_PHONE_NUMBER\",  \"otp\": \"code\",  \"realm\": \"sms\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}"

headers = { 'content-type': "application/json" }

conn.request("POST", "/{yourDomain}/oauth/token", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

require 'uri'
require 'net/http'
require 'openssl'

url = URI("https://{yourDomain}/oauth/token")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

request = Net::HTTP::Post.new(url)
request["content-type"] = 'application/json'
request.body = "{ \"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\",  \"client_id\": \"{yourClientId}\",  \"username\": \"USER_PHONE_NUMBER\",  \"otp\": \"code\",  \"realm\": \"sms\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}"

response = http.request(request)
puts response.read_body

imimport Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "grant_type": "http://auth0.com/oauth/grant-type/passwordless/otp",
  "client_id": "{yourClientId}",
  "username": "USER_PHONE_NUMBER",
  "otp": "code",
  "realm": "sms",
  "audience": "your-api-audience",
  "scope": "openid profile email"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://{yourDomain}/oauth/token")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()

Authenticate an Email user

cURL

curl --request POST \
  --url 'https://{yourDomain}/oauth/token' \
  --header 'content-type: application/json' \
  --data '{"grant_type": "http://auth0.com/oauth/grant-type/passwordless/otp", "client_id": "{yourClientId}", "username": "USER_EMAIL", "otp": "code", "realm": "email", "audience": "your-api-audience", "scope": "openid profile email"}'

var client = new RestClient("https://{yourDomain}/oauth/token");
var request = new RestRequest(Method.POST);
request.AddHeader("content-type", "application/json");
request.AddParameter("application/json", "{\"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\", \"client_id\": \"{yourClientId}\", \"username\": \"USER_EMAIL\", \"otp\": \"code\", \"realm\": \"email\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://{yourDomain}/oauth/token"

	payload := strings.NewReader("{\"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\", \"client_id\": \"{yourClientId}\", \"username\": \"USER_EMAIL\", \"otp\": \"code\", \"realm\": \"email\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("content-type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://{yourDomain}/oauth/token")
  .header("content-type", "application/json")
  .body("{\"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\", \"client_id\": \"{yourClientId}\", \"username\": \"USER_EMAIL\", \"otp\": \"code\", \"realm\": \"email\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}")
  .asString();

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://{yourDomain}/oauth/token',
  headers: {'content-type': 'application/json'},
  data: {
    grant_type: 'http://auth0.com/oauth/grant-type/passwordless/otp',
    client_id: '{yourClientId}',
    username: 'USER_EMAIL',
    otp: 'code',
    realm: 'email',
    audience: 'your-api-audience',
    scope: 'openid profile email'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

#import <Foundation/Foundation.h>

NSDictionary *headers = @{ @"content-type": @"application/json" };
NSDictionary *parameters = @{ @"grant_type": @"http://auth0.com/oauth/grant-type/passwordless/otp",
                              @"client_id": @"{yourClientId}",
                              @"username": @"USER_EMAIL",
                              @"otp": @"code",
                              @"realm": @"email",
                              @"audience": @"your-api-audience",
                              @"scope": @"openid profile email" };

NSData *postData = [NSJSONSerialization dataWithJSONObject:parameters options:0 error:nil];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://{yourDomain}/oauth/token"]
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:10.0];
[request setHTTPMethod:@"POST"];
[request setAllHTTPHeaderFields:headers];
[request setHTTPBody:postData];

NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                if (error) {
                                                    NSLog(@"%@", error);
                                                } else {
                                                    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
                                                    NSLog(@"%@", httpResponse);
                                                }
                                            }];
[dataTask resume];

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{yourDomain}/oauth/token",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{\"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\", \"client_id\": \"{yourClientId}\", \"username\": \"USER_EMAIL\", \"otp\": \"code\", \"realm\": \"email\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}",
  CURLOPT_HTTPHEADER => [
    "content-type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

import http.client

conn = http.client.HTTPSConnection("")

payload = "{\"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\", \"client_id\": \"{yourClientId}\", \"username\": \"USER_EMAIL\", \"otp\": \"code\", \"realm\": \"email\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}"

headers = { 'content-type': "application/json" }

conn.request("POST", "/{yourDomain}/oauth/token", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

require 'uri'
require 'net/http'
require 'openssl'

url = URI("https://{yourDomain}/oauth/token")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

request = Net::HTTP::Post.new(url)
request["content-type"] = 'application/json'
request.body = "{\"grant_type\": \"http://auth0.com/oauth/grant-type/passwordless/otp\", \"client_id\": \"{yourClientId}\", \"username\": \"USER_EMAIL\", \"otp\": \"code\", \"realm\": \"email\", \"audience\": \"your-api-audience\", \"scope\": \"openid profile email\"}"

response = http.request(request)
puts response.read_body

import Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "grant_type": "http://auth0.com/oauth/grant-type/passwordless/otp",
  "client_id": "{yourClientId}",
  "username": "USER_EMAIL",
  "otp": "code",
  "realm": "email",
  "audience": "your-api-audience",
  "scope": "openid profile email"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://{yourDomain}/oauth/token")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()

If you prefer, you can use the Android or iOS SDKs, which wrap this APIs in a platform-friendly way:

• Lock.Android Passwordless
• Lock.swift Passwordless
• Auth0.Android Passwordless
• Auth0.swift Passwordless

Customize MFA with Embedded

Customizable MFA with the Resource Owner Password Grant, Embedded, or Refresh Token flows is in Early Access. To learn more, read Product Release Stages. To participate in the early access, contact Auth0 Support.

Customize MFA with embedded flows. Use the MFA API to allow users to enroll and challenge with factors of their choice that are supported by your application.

When your application requests an access token at the oauth/token endpoint, the returned response includes the mfa_token to use the MFA API and the mfa_requirements parameter with a list of authenticators your application currently supports:

{
  "error": "mfa_required",
  "error_description": "Multifactor authentication required",
  "mfa_token": "Fe26...Ha",
  "mfa_requirements": {
    "challenge": [
      { "type": "otp" },
      { "type": "push-notification" },
      { "type": "phone" },
      { "type": "recovery-code" }
    ]
  }
}

Use the mfa_token to call the mfa/authenticator endpoint to list all factors the user has enrolled and match the same type your application supports. You also need to obtain the matching authenticator_type to issue challenges:

[
  {
    "type": "recovery-code",
    "id": "recovery-code|dev_qpOkGUOxBpw6R16t",
    "authenticator_type": "recovery-code",
    "active": true
  },
  {
    "type": "otp",
    "id": "totp|dev_6NWz8awwC8brh2dN",
    "authenticator_type": "otp",
    "active": true
  }
]

Proceed to enforce the MFA challenge by calling the request/mfa/challenge endpoint.

Further customize your MFA flow with Auth0 Actions. To learn more, read Actions Triggers: post-challenge - API Object.