Custom field with HTML and JavaScript

Implement specific logic or UI components in your forms using JS code. Pass data around, handle events, and make custom validations.

Custom field with HTML and JavaScript
Mutua Madrileña

How it works

Custom fields features

UI and logic with JavaScript

Add your own field UI and logic with a simple implementation that uses a JavaScript function with internal methods to store information, load external scripts or validate data.

Backend validations with JSON schema

Use the JSON schema standard to add backend validations to your custom fields. This adds a layer of security to validate field data structure: length of an array, object properties, string formats, etc.

Style your custom field with CSS

We have generic CSS classes and variables you can add to your source code to adapt your field style to the rest of your form. If you need further customization, you can always add your own CSS rules in our settings.

Get started with a template

Import a template with just a few clicks and adapt it to your needs


Signup form with Auth0

Learn how to add custom fields to your signup flow using Auth0.


Signup form with phone OTP verification with Amazon Cognito

Verify your users' phone number sending them a one-time-password (OTP) and sign them up with Amazon Cognito.

Amazon Cognito

Signup form with Supabase

A custom signup form with Supabase that collects basic information to create an account.


Passwordless login with Stripe Customer Portal

Allow your users to access the Stripe Customer Portal sending a magic link.


Signup form with phone OTP verification with Firebase

Verify your users' phone number sending them a one-time-password (OTP) and sign them up with Firebase.


Update/edit form with Airtable

Authenticate your users with email and allow them to edit/update their record information.

See all the templates

Other popular features

Discover what use cases you can build with Arengu

Security and privacy by default

We help you comply with your security and privacy policies. You decide where you want to store the information you collect, and who has access to it.

SOC 2 certified

Monitored by a 3rd party to stay compliant with SOC 2 security standards.

GDPR compliant

Full control of your data to help you comply with your privacy policies.

Hosted in the EU

Servers and data are securely hosted in the European Union.

Encrypted data

Data is stored encrypted using the AES256 algorithm.

Learn more about security

Out of the box integrations

Send your data back and forth between Arengu and your favourite apps.

Getting started with Arengu

Arengu allows you to build all your user flows connected to your current stack, and avoids coding all the UI, complex integrations, validations or logic from scratch. Try it for free and start building faster and scaling your application needs as they grow.