No credit card needed. Just download and go crazy for 7 days.
( Works on Mac OS 10.7 and above and Windows 7,8 and 10. No mobile version at the moment.)
To start a 7-day free trial, just enter your email above and then click the download button to download the app. After downloading, double-click the installer file to install. No credit card or pre-payment required. You get seven days to make some awesome simple diagrams.
The trial is feature complete, and you'll be able to save your diagrams.
Read about bug fixes and new features here: Product History
Behind the scenes, SimpleDiagrams uses Adobe AIR to make it easy for me to make a great cross-platform app. So if you want to know the base system requirements for SimpleDigrams, please review Adobe AIR's system requirements.
I love Linux. I want to publish a version for Linux. If you love Linux, please help me support it by emailing Adobe and asking them why they dropped Linux support for AIR.