diagrams.net

diagrams.net (formerly draw.io) is an open-source diagramming tool and self-hosted alternative to Lucidchart, Microsoft Visio, and Miro for creating technical diagrams, flowcharts, and architecture maps.

vs Lucidchart: Lucidchart is a cloud-based SaaS tool with per-user monthly pricing and diagrams stored on Lucid's servers. diagrams.net stores files locally or in your own cloud storage (Google Drive, OneDrive, GitHub), with no per-seat fees and no data-residency concerns. Lucidchart has richer real-time multi-user collaboration and a polished UX, but diagrams.net covers the full range of technical diagram types -- UML, ERDs, BPMN, network maps -- at zero licensing cost.

vs Microsoft Visio: Visio requires a Microsoft 365 subscription (Plan 2 or above, charged per user per month) and is Windows-centric, with files in a proprietary .vsdx format. diagrams.net is fully cross-platform, runs in any browser or as an offline desktop app, and stores diagrams as XML that remains readable without proprietary software. For teams outside the Microsoft ecosystem or those needing portable, vendor-neutral files, diagrams.net is the natural replacement.

vs Miro: Miro is an online whiteboard platform built for brainstorming, design sprints, and visual collaboration, with diagramming as one feature among many. It charges per editor and requires a persistent internet connection. diagrams.net is purpose-built for structured technical diagrams and can run entirely offline or be self-hosted for air-gapped environments -- making it the better fit for engineering and architecture documentation workflows.