REI3 — Self-Hosted, Open-Source

Features

• Fast results: Quickly replace spreadsheet based 'solutions' with proper multi-user applications.
• It can count: Summarize records, do date calculations, apply business rules and much more.
• Make things visible: Show tasks on Gantt charts, generate diagrams or display information-dense lists.
• Workflows included: Adjust forms based on the current state of a record, export to PDF or send notifications.
• Compliance tools: With roles and access policies, REI3 can give and restrict access globally or for specific records.
• End-to-end encryption: Built-in support for E2EE - easy to use with integrated key management features.
• Integration options: REI3 can serve as and call REST endpoints, create or import CSV files and offer ICS for accessing calendars.
• Ready for mobile: Works well on all devices, with specific mobile settings and PWA features for great-feeling apps.
• Fulltext search: Users can quickly find desired content by using search phrases and language specific lookups.
• Many inputs available: From simple date ranges, to drawing inputs for signatures, to bar- & QR code inputs that can scan codes via camera - REI3 offers a growing list of input types for various needs.

Installation

See official install docs: https://rei3.de/latest/x64_linux

Why self-host REI3

Self-hosting gives you three things SaaS can’t: data ownership (the files live on disks you control), cost predictability (a one-time setup vs. recurring per-seat fees that grow with your household or team), and longevity (open-source means the app keeps working even if the maintainers move on, since you can pin a working version). The trade-off is that you take on the operational work of running a server, applying updates, and handling backups.

What hardware do you need

Most self-hosted apps run comfortably on modest hardware — a Raspberry Pi 4, a mini PC, a NAS with Docker support, or a small VPS is usually enough for personal or family use. CPU and RAM requirements scale with how many simultaneous users or how much data you push through REI3. Storage requirements depend on the kind of data you keep; check the README for guidance on data retention.

Where to go from here

• Browse the full self-hosted app directory
• Compare self-hosted alternatives side-by-side
• DevOps roadmap — learn the skills to run your own server