Nextjournal was designed to make research easier to reproduce, reuse, and trust. It is a web-based application for creating living documents with executable code. The notebook-style multi-language programming and presentation environment focuses on long-term reproducibility. It is designed so that code the documents contain can be run and reused years later by automatically versioning the full software stack without requiring any knowledge of version control software. It was created to facilitate seamless collaborative development and sharing with the larger scientific community.