Embedded Passwordless Login in Regular Web Applications

To use the Embedded Passwordless APIs in Regular Web 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 Regular Web Applications consists of two steps:

1. 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, an SMS with a one-time-use code, or a magic link.
2. If you did not send a magic link, prompt the user for the one-time-use code, and call the /oauth/token endpoint to get authentication tokens.

Note that when using magic links, you don’t need to call /oauth/token. The user will click the magic link and be redirected to the application’s callback URL.

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

Send a one-time-use code via email

cURL

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

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

import Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "client_id": "{yourClientId}",
  "client_secret": "{yourClientSecret}",
  "connection": "email",
  "email": "{userEmail}",
  "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

You need to specify send: link.

cURL

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

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

import Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "client_id": "{yourClientId}",
  "client_secret": "{yourClientSecret}",
  "connection": "email",
  "email": "{userEmail}",
  "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}", "client_secret": "{yourClientSecret}", "connection": "sms", "phone_number": "{userPhoneNumber}","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}\", \"client_secret\": \"{yourClientSecret}\", \"connection\": \"sms\", \"phone_number\": \"{userPhoneNumber}\",\"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}\", \"client_secret\": \"{yourClientSecret}\", \"connection\": \"sms\", \"phone_number\": \"{userPhoneNumber}\",\"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}\", \"client_secret\": \"{yourClientSecret}\", \"connection\": \"sms\", \"phone_number\": \"{userPhoneNumber}\",\"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}',
    client_secret: '{yourClientSecret}',
    connection: 'sms',
    phone_number: '{userPhoneNumber}',
    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}",
                              @"client_secret": @"{yourClientSecret}",
                              @"connection": @"sms",
                              @"phone_number": @"{userPhoneNumber}",
                              @"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}\", \"client_secret\": \"{yourClientSecret}\", \"connection\": \"sms\", \"phone_number\": \"{userPhoneNumber}\",\"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}\", \"client_secret\": \"{yourClientSecret}\", \"connection\": \"sms\", \"phone_number\": \"{userPhoneNumber}\",\"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}\", \"client_secret\": \"{yourClientSecret}\", \"connection\": \"sms\", \"phone_number\": \"{userPhoneNumber}\",\"send\": \"code\"}"

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

import Foundation

let headers = ["content-type": "application/json"]
let parameters = [
  "client_id": "{yourClientId}",
  "client_secret": "{yourClientSecret}",
  "connection": "sms",
  "phone_number": "{userPhoneNumber}",
  "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}", "client_secret": "YOUR_CLIENT_SECRET", "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}\", \"client_secret\": \"YOUR_CLIENT_SECRET\", \"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}\", \"client_secret\": \"YOUR_CLIENT_SECRET\", \"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))

}

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}\", \"client_secret\": \"YOUR_CLIENT_SECRET\", \"username\": \"USER_PHONE_NUMBER\", \"otp\": \"code\", \"realm\": \"sms\", \"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}',
    client_secret: 'YOUR_CLIENT_SECRET',
    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}",
                              @"client_secret": @"YOUR_CLIENT_SECRET",
                              @"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}\", \"client_secret\": \"YOUR_CLIENT_SECRET\", \"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}\", \"client_secret\": \"YOUR_CLIENT_SECRET\", \"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}\", \"client_secret\": \"YOUR_CLIENT_SECRET\", \"username\": \"USER_PHONE_NUMBER\", \"otp\": \"code\", \"realm\": \"sms\", \"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}",
  "client_secret": "YOUR_CLIENT_SECRET",
  "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}", "client_secret": "{yourClientSecret}", "username": "{userPhoneNumber}", "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}\", \"client_secret\": \"{yourClientSecret}\", \"username\": \"{userPhoneNumber}\", \"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}\", \"client_secret\": \"{yourClientSecret}\", \"username\": \"{userPhoneNumber}\", \"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}\", \"client_secret\": \"{yourClientSecret}\", \"username\": \"{userPhoneNumber}\", \"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}',
    client_secret: '{yourClientSecret}',
    username: '{userPhoneNumber}',
    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}",
                              @"client_secret": @"{yourClientSecret}",
                              @"username": @"{userPhoneNumber}",
                              @"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}\", \"client_secret\": \"{yourClientSecret}\", \"username\": \"{userPhoneNumber}\", \"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}\", \"client_secret\": \"{yourClientSecret}\", \"username\": \"{userPhoneNumber}\", \"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}\", \"client_secret\": \"{yourClientSecret}\", \"username\": \"{userPhoneNumber}\", \"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}",
  "client_secret": "{yourClientSecret}",
  "username": "{userPhoneNumber}",
  "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()

Authenticate a user through a magic link

When you send a magic link, you don’t need to call an API to authenticate the user. Users will click the link and be redirected to the callback URL.

Setting the auth0-forwarded-for header for rate-limit purposes

The /passwordless/start endpoint has a rate limit of 50 requests per hour per IP. If you call the API from the server-side, your backend’s IP may easily hit these rate limits. To learn how to address this issue, read the Rate Limiting in Passwordless Endpoints section of Using Passwordless APIs.

Customize MFA

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 using Lock for Web, the oauth/token endpoint returns the mfa_required error and includes the mfa_token you need to use the MFA API and 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" }
      { "type": "email"} //can only work with challenge
    ]
  }
}

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.