Hidden fields for custom signup forms

Automatically populate HTML hidden inputs in your signup and login forms. Collect users data from cookies, UTMs, and URL parameters without effort.

Hidden fields for custom signup forms

HTML hidden inputs in forms

Reduce friction by filling-in hidden fields with custom data from the URL. Automatically get user information from cookies and tracking parameters, like UTMs. Enrich your user database and improve your marketing strategy without effort.

How it works

Create a hidden field. Click on the ‘Hidden fields’ button, on the upper part of the form editor, to add a hidden field to the form.

Give it a name. Add the field name in the left column. If you're getting a parameter out of the URL, just make sure their names match.

Reference its value. Add a fixed value on the right column, if needed. If you haven't set any values from the URL nor the SDK, they will be automatically taken.

Publish and test it. Publish the form and click on the ‘Preview’ button to test it.

Check the data. Go to the ‘Submissions’ tab to see the list of field values, including the hidden fields. Then click on ‘Metadata’ to see additional values and details about the submission, including the URL and UTMs you have set.

Other Forms features

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

Learn about Forms


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.

Learn about Flows


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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Out of the box integrations

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