Gleek alternatives: 4 open-source picks
These 4 Gleek alternatives replace it for $0, led by Mermaid Live Editor, PlantUML Server and Excalidraw. All 4 are open source. License, stars and last commit checked by hand on 2026-08-29. No trials, no crippled tiers.
Type Mermaid, see the diagram immediately, and export it; narrower than Gleek, but finished, free, and pleasantly uncomplicated.
A usable browser editor for architecture, sequence, process, and data-model diagrams written as text; the syntax is less forgiving than Gleek's.
Virtual hand-drawn style whiteboard for sketching diagrams collaboratively
licenseMIT
runsyour server
setupnot verified by us yet — check the repo README
facts verified 2026-08-29
The diagramming workhorse — flowcharts, architecture diagrams, UML — runs fully client-side or as your own container.
licenseApache-2.0
runsyour server
setupnot verified by us yet — check the repo README
facts verified 2026-08-29
What each one is, in full: Excalidraw · draw.io
last updated 2026-08-29 · no votes, no pay-to-list · just what's real
how to choose a Gleek alternative
Easiest to get running
Excalidraw — a one-click install, no server to maintain.
Most proven
Excalidraw, with 129,000 GitHub stars — the largest community of the 4, which usually means more answers when something breaks.
what you give up by leaving Gleek
- multiplayer cursors and comments
- large template libraries
- high-fidelity import and export
- presentation and enterprise controls
None of the picks above covers all of it. The full verdict says which gaps matter.
Gleek alternatives at a glance
| tool | license | running it | platforms | stars | active |
|---|---|---|---|---|---|
| Mermaid Live Editor | open source | they host it | web, self-hosted | 6,719 | 2026-08 |
| PlantUML Server | open source | they host it | web, self-hosted | 2,210 | 2026-06 |
| Excalidraw | MIT | one-click install | self-hosted, web | 129,000 | 2026-08 |
| draw.io | Apache-2.0 | one-click install | self-hosted, web | 43,000 | 2026-08 |
why people still pay for Gleek
Gleek: The shapes are easy; customers pay for low-friction editing, reliable exports, collaboration, and a canvas that never fights them.
questions about switching from Gleek
Is there an open-source alternative to Gleek?
Yes: Mermaid Live Editor, PlantUML Server, Excalidraw and 1 more. Every tool on this page is open source: no trials, no crippled tiers.
Can open source really replace Gleek?
Our verdict is YES. Excalidraw (129k stars), draw.io (43k stars), Mermaid Live Editor (7k stars) are mature open-source replacements for Gleek — self-host in one command and stop paying. The full verdict, and what you give up by switching, is at caniopensourceit.online/gleek.
What is the easiest open-source Gleek alternative to set up?
Excalidraw — a one-click install, no server to maintain.
What is the most popular open-source Gleek alternative?
By GitHub stars, Excalidraw (129,000). draw.io is next with 43,000.
