jsPsych

jsPsych is an open-source JavaScript library for creating behavioral experiments that run in a web browser. It is designed for researchers in psychology, neuroscience, and related fields who need to deploy studies online or in classroom settings without specialized software. The project is hosted on GitHub and released under the MIT license, ensuring wide accessibility and extensibility.

At its core, jsPsych uses a timeline model: researchers assemble a sequence of trials, each implemented as a plugin, to present stimuli and collect responses. Plugins cover a wide range of tasks, including perception and attention tasks, memory probes, surveys, and reaction-time measurements. When an experiment runs, jsPsych records data from each trial (stimulus, response, reaction time, and metadata) and stores it in JSON or CSV format for analysis.

The library emphasizes modularity and extensibility. Developers can write new plugins or reuse existing ones to support custom stimuli, response devices, and data formats. It integrates with standard web technologies and can post data to servers or export files for offline analysis. jsPsych experiments can be hosted on common platforms such as GitHub Pages or Pavlovia.

Since its inception, jsPsych has become a widely used tool in online experimentation, supported by an active community of researchers and contributors. Its open design and browser-based deployment reduce the barriers to conducting scalable behavioral studies.