LimeSurvey (nix)

LimeSurvey is a mature, open-source survey platform written in PHP that lets you design and publish online surveys, questionnaires, and forms without writing code. It is a self-hosted alternative to SurveyMonkey, Typeform, Qualtrics, and Google Forms, and is widely used by academic institutions, businesses, and public bodies.

It supports an extensive range of question types, conditional logic and branching, quotas, multilingual surveys, customizable themes, and access control via tokens. Responses can be collected anonymously or tracked, exported to common formats (CSV, Excel, SPSS, R), and analyzed with built-in statistics and charts. It stores data in MySQL, MariaDB, PostgreSQL, or MSSQL.

Typical use is running self-administered surveys where you need full control over your data and respondent privacy — for example research studies, customer feedback, event registration, and GDPR-sensitive data collection hosted on your own server.