The best open source alternative to Wufoo is OhMyForm, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Wufoo and seven of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Wufoo are LiquidFeedback (Free, Open Source), Formspree.io (Freemium, Open Source), ApPHP DataForm (Paid, Open Source) and FormBucket (Paid, Open Source).
OhMyForm is a free and open source alternative to commercial form creators like Typeform and Google Drive - Forms providing all the features you need to run, administer, analyze and distribute forms for free.
ApPHP DataForm script is a simple tool for creating HTML forms with ease. It was especially designed for web developers, who do not want to spend excessive time on creating forms in HTML or through PHP, but want to use a first-class OOP backend.
FormBucket gives you a hosted endpoints for your static site forms. Your markup, your CSS. We take care of the rest. You can redirect users to any URL, send autoresponder emails and add unlimited webhooks.
Quill forms is a free Typeform alternative for WordPress which enables you to design engaging and interactive quizzes for free. It comes with a lot of features like drag and drop question types, having multiple themes, customizing messages and more!.