SMS & Email OTP verification

SMS & email verification with one-time passwords

Reinforce the security of your registration forms by easily implementing OTP via email or SMS


Try an email OTP flow demo

This working demo generates an OTP and sends it via email.

✉️ Generate OTP

This first step has a flow that verifies if the email domain has a valid MX record, if it's valid, it generates a 4-digit OTP and sends it via email using Mailjet.

Try it using an email with non existing domain and another one which you have access to verify the OTP.

What our clients say

"With Arengu, we are able to easily experiment and test our sign up flow, by separating it from our core platform. At the same time, the flow has become more robust when it comes to eliminate errors."
Peter Hanekamp
CEO, Taiga
"Arengu is a key part of our acquisition strategy to build personalized sign-up pages at scale. They are a flexible and easy-to-use solution to achieve our business goals."
Tahís Gómez
Acquisition Marketing, Privalia
"Thanks to Arengu we've been able to improve our customer registration experience, increasing the conversion rates by 30%. All in a quick and easy way."
Rafa Rovira
Digital Marketing Manager, Khama
"Arengu is a quick, trustworthy and flexible solution that allowed us to launch faster in new international markets and keep our focus in our core platform."
Borja Maceira
CTO, Opositatest

Why use SMS or email verification with Arengu?

Verify & qualify users

Use one-time passwords to verify your users’ identity and get qualified leads by sending them to your users’ email or phone number. Make sure you acquire users that will convert by ensuring their identity is truthful.

OTPs can be equally sent to the users’ email addresses or phone numbers, so you can use them as a cross-device security system and be double sure your users are who they claim they are.

Reinforce your flows security

Data is the new bacon. Protect your users’ data and your business by implementing SMS or email verification, either as a standalone verification method or a part of a multi-factor authentication strategy.

SMS and email verification add a strong security layer that helps you tackle malicious attempts, such as account takeovers or data theft.

Avoid fraud & block spam

Clean up your database by blocking automated fraudulent attacks, such as spam accounts or bots — the majority of attacks in the internet. 

Make your forms fraud proof by implementing verification systems that are user friendly and easy to implement. Tackling automated identity attacks from the forms will help you keep a cleanusers database.

Powerful alone. Better together.

All-in-one solution to build, automate and scale your signup flows.


Drag & drop form builder

Easily create your custom form with our drag & drop builder. Add multiple steps, require payment details, add custom server-side logic... without writing a single line of code.

  • Forms with Flows

  • Approval workflows

  • Multi-step forms fields

  • Payment fields

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Visual flow editor

Easily build server-side logic that can be used in your forms or as a standalone product. Create custom validations, integrate with other APIs or automate tasks without coding.

  • Validation flows

  • Eliminate maintenance costs.

  • Easy to integrate with your stack.

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Hosted static pages

Maximize your conversion rates building dedicated static pages at scale with message-matched content and get the best results for your ad campaigns.

  • Simple HTML templates

  • Automated pages from a .CSV file

  • HTTPS & CDN-hosted assets

  • Mustache template tags

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Other popular use cases

Use ready-made templates to build complex use cases in minutes. Or build yours from scratch for a completely custom experience.

Developer friendly

Save development time, embed anywhere with a line of code.

Stack agnostic

Embed it, with a simple line of code, in most popular CMS platforms, landing page builders and development frameworks.

Integrations with any API

Quick integration with almost every API and common ID providers (Auth0, Okta...), adding flexibility to forms and logics.

Save time and resources

We help teams with repetitive and complex actions, building - easy to edit, maintain and scale - templates.

Frequently asked questions

How does an OTP work? How are OTPs generated?
What is an OTP? What does OTP mean?
Why should I use an OTP verification?
Can I set up passwordless forms with OTPs?
What is two-factor authentication (2FA)?
Can I use my own email or SMS provider?
Does Arengu support email templates for OTPs? Can I customize the OTP message?
Does Arengu support a native email address verification action?
Pros and cons of email and SMS verification: Which is the best option?