SoSci Survey is an online service (also available for self-hosting) to easily create and publish online questionnaires. It's been founded in 2006 and grown ever since. Due to its enormous flexibility, SoSci Survey its intensively used by social researchers, and commercial research institutes who need enhanced features or need to comply to high privacy standards. Sosci Survey's USPs are a substantial range of features (uncounted types of questions, invitation management, fully labelled SPSS and GNU R output, intuitive user interface and extensive handbook, multiple pre-defined responsive design templates, use of images, audio, and video files, response probing, pretest features, piping, and many more) and even more professional features (use of HTML and JavaScript, working with own design and question templates, integration of commercial access panels, sending email and SMS invitations, automated reminders, various access restrictions, preview URLs for third parties), and no less features for complex questionnaires (fully programmable questionnaires and conditional questions, dynamic content, multilingual surveys and international charsets via UTF-8, experimental randomization, embedding of external survey tools, mobile experience sampling/MESM, passing external data to interviews, etc.). As SoSci Survey is rooted in university research, the online service is freely available to non-commercial research (i.e., most university courses and BA, MA, and PhD theses) with only one limitation, which is a maximum 5000 interviews per survey project. The software is available in English and German, questionnaires can be created in any known language.