Baserow
Airtable's spreadsheet-database model, self-hostable and open-source: that is Baserow. It presents data in a spreadsheet-style grid, but underneath each table is a real relational structure with typed fields, links between tables, filters, sorts, and multiple views (grid, gallery, form, kanban, calendar). Beyond the database core, it includes an application builder for composing pages and portals on your data, workflow automations, and dashboards. Everything is API-first: each table exposes a REST endpoint with token auth and webhooks, so it plugs directly into n8n, Zapier, or custom scripts. The stack is Django (Python) on the backend, Vue.js on the frontend, PostgreSQL for storage, with Redis for async tasks. Core features are MIT-licensed; premium features are a paid add-on. The self-hosted version has no row, storage, or API request limits - Airtable's per-base record caps and monthly API quotas simply don't exist here, and capacity is bounded only by your PostgreSQL database and disk. Existing Airtable bases, CSVs, and Excel files import directly with structure preserved, so migration doesn't start from a blank slate, and both the backend and frontend support plugins for custom field types and integrations without forking the core. For non-technical teammates the interface behaves like a spreadsheet; for engineers, the data model is the API.
REI3
Replace the spreadsheet that quietly runs your department with a proper multi-user application that you design in a browser with REI3, a self-hosted low-code platform. Authors define their data model once, then assemble forms, lists, calendars, Gantt plans, Kanban boards, and charts around it, with form states that show, hide, or require inputs as a record moves through its workflow. Calendars create records from a drag-selected time range, Kanban cards change state by drag and drop, and bulk-update forms edit hundreds of records at once. Phones scan barcodes and QR codes through the camera, and signature pads capture drawings. Roles and record-level access policies decide who sees what, sign-in runs through LDAP, OpenID Connect, or multi-factor authentication, and end-to-end encryption keeps selected fields unreadable even to administrators. REST endpoints work in both directions, ICS feeds publish calendars, CSV moves data in bulk, and IMAP and SMTP accounts connect applications to email. A drag-and-drop PDF editor produces letterheads, labels, and documents with signatures and barcodes. More than a dozen free ready-made applications, including tickets, time tracking, IT assets, a password safe, and a CRM, install from the admin panel. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.