Houdini is described as 'all-in-one fundraising platform developed in Ruby on Rails. It’s licensed under AGPL/LGPL and vailable, without cost, to anyone in the world' and is a Crowdfunding Service in the category. There are more than 25 alternatives to Houdini for a variety of platforms, including Online / Web-based, Android, iPhone, SaaS and Self-Hosted solutions. The best alternative is Liberapay, which is both free and Open Source. Other great apps like Houdini are PayPal (Paid), Open Collective (Freemium, Open Source), Patreon (Paid) and Flattr (Paid).
Flattr is a social micropayment service, that makes it easy for you to "flatter" things on the internet that you like. When you're registered to Flattr, you pay a small monthly fee of your own choosing.
GNU Taler is a privacy-preserving payment system. Customers can stay anonymous, but merchants can not hide their income through payments with GNU Taler. This helps to avoid tax evasion and money laundering.
Goteo is a social network for crowdfunding and distributed collaboration (services, infrastructures, microtasks and other resources) for encouraging the independent development of creative and innovative initiatives that contribute to the common good, free knowledge, and open...