The Flattr colors are Flattr Pumpkin, Slimy Green, we recommend using the Flattr color palette for personal projects and in the case of commercial use to visit the company website. The color codes: RGB, CYMK for print, and Hex for web HTML/CSS. Flattr Official Website
Download the Flattr color scheme palette image with the color hex codes as a single image. These are the suggested colors to be used for digital media.