Open Source Spreadsheet
Most tools in this category answer two different needs that people lump together. One is a real calculating spreadsheet that opens your existing workbooks, preserves formulas, and recalculates the same numbers. The other is a database wearing a grid, where typed columns, links between tables, and an API matter more than cell math. Open source lets you keep either one on infrastructure you control: the workbook editors run offline on your own machine, and the database-style tools store rows in a database you host and can query directly, instead of leaving years of shared data trapped in one vendor's cloud.
NocoDB
Self-hostable no-code platform that turns any database into a spreadsheet interface
Teable
Spreadsheet-like no-code Postgres for building database apps and team workflows
APITable
API-oriented low-code spreadsheet for collaborative apps, automation, and embedded database views
Grist
Relational spreadsheet software that combines spreadsheet flexibility with database structure
ONLYOFFICE Docs
Collaborative online office suite for documents, spreadsheets, presentations, forms, PDFs, and diagrams
Baserow
Open source no-code database and app builder with AI, automations, dashboards, and self-hosting
LibreOffice
Free open source office suite with Writer, Calc, Draw, Impress, and broad document format support
EtherCalc
Web spreadsheet for real-time collaborative editing with self-hosting via Docker Compose or Cloudflare
undb
Open source no-code database and BaaS built on SQLite for local-first, self-hosted data management
Our picks
The right pick depends on whether you want a true spreadsheet or a shared database with a grid on top.
Best for a grid over an existing database: NocoDB NocoDB connects to an existing MySQL or PostgreSQL database and turns it into a spreadsheet-style workspace with grid, form, kanban, and calendar views. The database stays the source of truth, and REST APIs plus an SDK expose every table for teams that already run SQL.
Best for spreadsheet power users: Grist Grist keeps a spreadsheet's flexibility but adds database-style columns and references, and it runs Python formulas alongside familiar Excel functions. Each document is a portable SQLite file you can back up like any other, and the same app runs as a server, a desktop install, or in the browser.
Best no-code database for teams: Baserow Baserow pairs a spreadsheet-style grid with a PostgreSQL backend and an application builder that publishes apps and portals on your own domain. Automations, dashboards, and an API-first design help a non-technical team grow a shared table into an internal tool; the core is MIT-licensed with no self-hosted storage limits.
Best true spreadsheet for Office files: ONLYOFFICE Docs ONLYOFFICE Docs is the pick when you need an actual calculating spreadsheet, not a database. It is built around Office Open XML, so .xlsx workbooks open and save with high fidelity, and it supports real-time co-editing across a suite you deploy on your own servers.
Spreadsheet or database: which one you actually need
The first fork in the road is whether you want a spreadsheet or a database that looks like one. If you exchange .xlsx files with the outside world, run heavy formulas, or need faithful print layouts, you want a genuine workbook editor like LibreOffice Calc or ONLYOFFICE, and your test should be your messiest real workbooks - volatile formulas, array formulas, merged cells, and locale-specific separators - not a clean sample. If instead your spreadsheet is really a shared list that ten people edit and other systems read, a relational tool like NocoDB, Baserow, or Grist will serve you better, because typed columns and links stop the quiet data rot that plain grids invite.
Where the data lives is the second decision. NocoDB points at an existing MySQL or PostgreSQL database and turns it into a grid, which suits teams that already run a database and want it to stay the source of truth. Teable and Baserow store rows in Postgres and expose a REST API, so records stay queryable outside the app. Grist is unusual in that it can run as a server, a desktop app, or entirely in the browser, and it keeps each document as a portable SQLite file you can copy and back up like any other file.
Automation is where these tools quietly become application platforms, so treat it as a first-class requirement. Look for a documented API, webhooks, and formula support you can actually maintain: Grist runs full Python formulas, while the Airtable-style tools lean on spreadsheet-like formula fields. Whatever you pick, confirm the exit path before you load years of data - export that preserves formulas and structure, not just final values.
Related categories
Frequently asked questions
What is the difference between a spreadsheet and a spreadsheet-database tool?+
A spreadsheet like LibreOffice Calc or ONLYOFFICE calculates in free-form cells and reads .xlsx files. A spreadsheet-database like NocoDB, Teable, or Baserow looks similar but stores typed records in a real database, with links between tables, forms, and multiple views. If you need formulas and file fidelity, pick the former; if you need shared, structured data that other systems query, pick the latter.
Will these open my existing Excel files correctly?+
The office suites are built for it: ONLYOFFICE targets Office Open XML directly, and LibreOffice Calc opens most .xlsx and .ods workbooks. Perfect fidelity is never guaranteed, though - pivot tables, charts, macros, external links, and unusual layouts carry the most risk. Test with your real files, not templates: open, recalculate, save, reopen, and compare both the values and the visual layout before you move a team over.
Which of these support real-time collaborative editing?+
Several do, in different ways. EtherCalc is built entirely around it - share a room URL and edit the same sheet together. ONLYOFFICE offers real-time co-editing of workbooks, and the database-style tools like Teable and APITable are designed for many people entering data at once. For live multi-user budget reviews, test with a realistic number of editors and a real workbook size rather than assuming it behaves like a single-user file.
Can other systems read the data through an API?+
This is a strength of the database-style tools. NocoDB, Teable, undb, and Baserow all expose REST APIs, and APITable adds a Datasheet Query Language for SQL-like queries, so a grid can feed dashboards, scripts, or other apps. Grist adds webhooks alongside its REST API. If your spreadsheet is really a system boundary, prefer these over a plain workbook editor, which was never designed to be queried programmatically.
Do any of these keep working offline?+
Yes. LibreOffice is a desktop suite that runs fully offline, and Grist ships a desktop app plus an in-browser build that work without a server. undb follows a local-first approach and can run from a single binary. The browser-based collaborative tools generally expect a running server, so if uninterrupted offline editing matters, favor the desktop or local-first options and keep periodic backups of the file.
Which tool fits a non-technical team versus developers?+
Non-technical teams tend to do best with a no-code grid such as Baserow or Teable, where forms, views, and formula fields need no setup beyond the browser. Developers who want the database itself as the source of truth often prefer NocoDB, which sits on top of an existing SQL database, or undb, which doubles as a backend-as-a-service. Grist splits the difference with Python formulas for people comfortable writing a little code.
Can I turn a grid into a simple app or portal?+
Some of these go well beyond data entry. Baserow includes an application builder that publishes apps and portals on your own domain, plus automations and dashboards. APITable is built as a low-code platform with dashboards and automation hooks into tools like n8n and Zapier. If you want the grid to become a lightweight internal tool rather than just a table, check for an app builder and automation actions specifically.