LimeSurvey (PHPSurveyor) is a free and open source on-line survey application written in PHP based on a MySQL, SQLite, PostgreSQL or MSSQL database, distributed under the GNU General Public License.
Developed by Carsten Schmitz / The LimeSurvey team
SmartSurvey is a SaaS platform where users can capture, analyse and report virtually any type of data via a simple, yet stylish, online survey service.
SurveyNuts is an online survey software designed to help users quickly create online and mobile questionnaires, gather answers, and view results graphically.