Passcodes overview

Our flexible one-time passcodes (OTP) can be sent via SMS, WhatsApp, or email, and allows you to use this method as the primary factor or as a two-factor authentication to strengthen security.

API reference SDK reference

Types of passcodes

SMS OTP

Build an authentication flow that texts a one-time, numeric code to your users' mobile devices, which they can then enter to log in.

WhatsApp OTP

For reliable deliverability and an international user audience, leverage our WhatsApp OTPs.

Email OTP

Enable seamless cross device logins across desktop and mobile with our Email OTPs.

Example apps with Passcodes

Learn more about how Stytch works and get up and running quickly using an example app. Want to dive into the products but not the code? Try out our demo app.

Backend example apps

Leverage Stytch's flexibility to control authentication from your backend.

Mobile example apps

Leverage Stytch's flexibility to control authentication from your backend.

Coming Soon

SMS one-time passcodes

Step-by-step guides to quickly get up and running with Stytch SMS one-time passcodes.

Setting up a new auth solution with SMS

Integrate Stytch one-time passcodes as your authentication solution.

Step 1: Build your UI for SMS login
Here’s an example of an authentication flow. One screen accepts the user’s phone number and the other accepts their one-time passcode.
Step 2: Login or create user
The LoginOrCreateUserBySMS endpoint will be used to log in or sign up a user. This request will send a one-time passcode to the provided phone number. By default, the code will expire in 2 minutes. You can alter the expiration with the ExpirationMinutes request field. If the phone number isn’t associated with a user yet, a user will be created. If the user_created attribute in the response is true, save the user ID and phone ID from the response. We recommend saving these IDs in new columns of your users table or within a new table linking your users with their Stytch IDs.
```
curl --request POST \
	--url https://test.stytch.com/v1/otps/sms/login_or_create \
	-u 'PROJECT_ID:SECRET' \
	-H 'Content-Type: application/json' \
	-d '{
	    "phone_number": "+12025550162"
	}'
```
Step 3: Authenticate one-time passcode
The AuthenticateOTP endpoint will be used in conjunction with all LoginOrCreateUserBySMS requests. The user should be prompted to enter the one-time passcode sent to them via SMS. After the user enters their code, send an AuthenticateOTP request with the code along with the phone ID used. If the response is a 200, the user is verified and can be logged in. If you'd like to keep this user logged-in for a while, include "session_duration_minutes": 60 (an hour, for example). Check out the session management guide to learn how to handle the session.
```
curl --request POST \
	--url https://test.stytch.com/v1/otps/authenticate \
	-u 'PROJECT_ID:SECRET' \
	-H 'Content-Type: application/json' \
	-d '{
	    "method_id": "phone-number-test-d5a3b680-e8a3-40c0-b815-ab79986666d0",
        "code": "123456"
	}'
```

Getting started with a SDK

This guide is coming soon.

Add multi-factor authentication (MFA) with SMS

Integrate Stytch one-time passcodes (OTP) as your multi-factor authentication solution.

Step 1: Build your UI for multi-factor authentication
Here’s an example of a multi-factor authentication flow. One screen accepts the user’s phone number and the other accepts their one-time passcode.
Step 2: Create or update user
The user you want to authenticate needs to be a Stytch user with an associated phone number. If they are, continue to Step 3. If the user already has a Stytch ID, send a UpdateUser request to add a phone number. If they don’t, send a CreateUser request to create a user with a phone number. We recommend saving the user and phone IDs in new columns of your users table or within a new table linking your users with their Stytch IDs.
```
curl --request POST \
	--url https://test.stytch.com/v1/users \
	-u 'PROJECT_ID:SECRET' \
	-H 'Content-Type: application/json' \
	-d '{
		"phone_number": "+12025550162"
	}'
```
Step 3: Send one-time passcode
Now that the phone number is associated with a Stytch user, send a SendOTPBySMS request. This will send a one-time passcode to the provided phone number. By default, the code will expire in 2 minutes. You can alter the expiration with the ExpirationMinutes request field.
```
curl --request POST \
	--url https://test.stytch.com/v1/otps/sms/send \
	-u 'PROJECT_ID:SECRET' \
	-H 'Content-Type: application/json' \
	-d '{
	    "phone_number": "+12025550162"
	}'
```
Step 4: Authenticate one-time passcode
The AuthenticateOTP endpoint will be used in conjunction with all SendOTPBySMS requests. The user should be prompted to enter the one-time passcode sent to them via SMS. After the user enters their code, send a AuthenticateOTP request with the code along with the phone ID used. If the response is a 200, the user is verified and can be logged in.
```
curl --request POST \
	--url https://test.stytch.com/v1/otps/authenticate \
	-u 'PROJECT_ID:SECRET' \
	-H 'Content-Type: application/json' \
	-d '{
	    "method_id": "phone-number-test-d5a3b680-e8a3-40c0-b815-ab79986666d0",
        "code": "123456"
	}'
```

Unsupported countries

Stytch does not support sending SMS passcodes to the following countries:

Afghanistan
Albania
Andorra
Angola
Aruba
Azerbaijan
Bahamas
Barbados
Belarus
Belize
Bermuda
Bhutan
Bosnia and Herzegovina
Botswana
British Virgin Islands
Burma (Myanmar)
Cambodia
Cape Verde
Cayman Islands
China – including Hong Kong
Congo, Dem Rep
Cote D’Ivoire (Ivory Coast)
Cuba
Curaçao and Caribbean Netherlands (Bonaire, Sint Eustatius, Sint Maarten, Saba)
Cyprus
Democratic Republic of Congo
Denmark
Dominica
Equatorial Guinea
Eritrea
Estonia
Faroe Islands
Fiji
French Polynesia
Gabon
Gambia
Gibraltar
Greenland
Guadeloupe
Guam
Guinea
Haiti
Indonesia
Iran
Iraq
Ivory Coast
Jordan
Korea Dem People's Rep
Kosovo
Kuwait
Kyrgyzstan
Laos PDR
Lebanon
Lesotho
Liberia
Libya
Macau
Macedonia
Madagascar
Malawi
Malaysia
Maldives
Mali
Martinque
Mongolia
Montserrat
Mozambique
Namibia
Nepal
New Caledonia
Niger
North Korea
Northen Mariana Islands
Oman
Pakistan
Palestine
Papua New Guinea
Philippines
Republic of North Macedonia
Reunion/Mayotte
Russia
Rwanda
Senegal
Serbia
Sierra Leone
Solomon Islands
Somalia
Sri Lanka
St Vincent Grenadines
Sudan
Sweden
Syria
Tajikistan
Thailand
Turkmenistan
Turks and Caicos Islands
U.S. Virgin Islands
Uganda
Uzbekistan
Venezuela
Vietnam
Yemen
Zimbabwe

If you attempt to send an SMS to an international code which corresponds with a country listed above the API will return an invalid_phone_number_country_code error. Please reach out to support@stytch.com if you have any questions.

Passcodes overview

Types of passcodes

SMS OTP

WhatsApp OTP

Email OTP

Example apps with Passcodes

Backend example apps

T3 stack

GitHub

Mobile example apps

iOS

GitHub

Android

GitHub

Flutter

Coming Soon

React Native

GitHub

Expo

GitHub

SMS one-time passcodes

Setting up a new auth solution with SMS

Step 1: Build your UI for SMS login

Step 2: Login or create user

Step 3: Authenticate one-time passcode

Getting started with a SDK

Add multi-factor authentication (MFA) with SMS

Step 1: Build your UI for multi-factor authentication

Step 2: Create or update user

Step 3: Send one-time passcode

Step 4: Authenticate one-time passcode

Unsupported countries