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PlantUML alternatives: 5 apps ranked by verified data

Facts checked Oct 25, 2026AppBreakup editorialHow we rank

Common reasons people leave PlantUML: default visual style looks dated, and local use needs Java installed. We ranked 5 alternatives by how directly each one replaces PlantUML, then by reviews, real visits and how recently each app's facts were checked against its own website. Mermaid currently ranks first.

Quick comparison

#AppPricingOpen sourcePlatformsVerified factsScore
1Mermaid logoMermaidOpen sourceYesWeb, Self-hosted4 of 466.5
2D2 logoD2Open sourceYesWindows, macOS, Linux +15 of 562.6
3Structurizr logoStructurizrOpen sourceYesWeb, Self-hosted4 of 459.6
4Gleek logoGleekFree plan + paidNoWeb4 of 455.3
  1. Mermaid logo

    1. MermaidTop pick

    Best for: Developers who want diagrams as text that render in GitHub, docs and wikis

    Open sourceSelf-hostableWeb, Self-hosted

    66.5

    score / 100

    Why switch from PlantUML

    Simpler syntax and native rendering on GitHub and GitLab without a server.

    Pros

    • Diagrams are plain text you can version and review
    • Rendered natively by GitHub, GitLab and many doc tools
    • Free and MIT licensed
    • Covers many diagram types

    Cons

    • Little control over layout
    • Large diagrams become hard to read
    • Styling options are limited
    Visit Mermaid Compare with PlantUMLDetails and reviews
    How this score is calculated
    Editorial fit ×0.3100
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.1585
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Mermaid a good PlantUML alternative?

    Verified facts

    4 of 4 verified
    License
    MIT
    Checked Oct 25, 2026github.com(opens source in a new tab)
    Syntax
    Markdown-inspired text definitions
    Checked Oct 25, 2026mermaid.js.org(opens source in a new tab)
    Online editor
    Mermaid Live Editor
    Checked Oct 25, 2026mermaid.js.org(opens source in a new tab)
    Award
    2019 JavaScript Open Source Award
    Checked Oct 25, 2026mermaid.js.org(opens source in a new tab)
  2. D2 logo

    2. D2

    Best for: Developers who want diagrams as code with more layout and styling control than Mermaid

    Open sourceWindows, macOS, Linux, Web

    62.6

    score / 100

    Why switch from PlantUML

    Modern text-to-diagram language with nicer default layouts and themes.

    Pros

    • Clean default output with themes and custom fonts
    • Multiple layout engines to choose from
    • Offline CLI with live-reload watch mode
    • Modular diagrams through imports

    Cons

    • Not rendered natively on GitHub
    • Smaller ecosystem than Mermaid or PlantUML
    • Still needs a CLI or plugin to render
    Visit D2 Details and reviews
    How this score is calculated
    Editorial fit ×0.387
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.1585
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is D2 a good PlantUML alternative?

    Verified facts

    5 of 5 verified
    License
    MPL-2.0
    Checked Oct 25, 2026github.com(opens source in a new tab)
    Platforms
    macOS, Linux, Windows
    Checked Oct 25, 2026d2lang.com(opens source in a new tab)
    Project
    Independent, fiscally sponsored by Hack Club
    Checked Oct 25, 2026d2lang.com(opens source in a new tab)
    CLI
    Local CLI with watch mode
    Checked Oct 25, 2026d2lang.com(opens source in a new tab)
    Custom fonts
    Your own .ttf files
    Checked Oct 25, 2026d2lang.com(opens source in a new tab)
  3. Structurizr logo

    3. Structurizr

    Best for: Software architects documenting systems with the C4 model as code

    Open sourceSelf-hostableWeb, Self-hosted

    59.6

    score / 100

    Why switch from PlantUML

    Better for architecture: one model, many C4 diagrams kept in sync.

    Pros

    • One model generates many consistent diagrams
    • Reference implementation of the C4 model
    • Text DSL works well in version control
    • Self-hostable

    Cons

    • Only for software architecture diagrams
    • DSL has a learning curve
    • Server edition binaries need a paid licence
    Visit Structurizr Details and reviews
    How this score is calculated
    Editorial fit ×0.377
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.1585
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Structurizr a good PlantUML alternative?

    Verified facts

    4 of 4 verified
    Approach
    Models as code for the C4 model
    Checked Oct 25, 2026structurizr.com(opens source in a new tab)
    Open source
    Yes
    Checked Oct 25, 2026structurizr.com(opens source in a new tab)
    Pricing
    Free except prebuilt server binaries
    Checked Oct 25, 2026docs.structurizr.com(opens source in a new tab)
    Creator
    Author of the C4 model
    Checked Oct 25, 2026structurizr.com(opens source in a new tab)
  4. Gleek logo

    4. Gleek

    Best for: Developers and analysts who want quick text-typed diagrams in the browser

    Free plan + paidWeb

    55.3

    score / 100

    Why switch from PlantUML

    Keyboard-driven text-to-diagram tool in the browser with no setup.

    Pros

    • Keyboard-only workflow, no dragging
    • Supports flowcharts, UML and ER diagrams
    • Nothing to install
    • Inexpensive premium plans

    Cons

    • Free plan limited to 5 files and 40 objects
    • Free diagrams are stored only in the browser
    • Smaller community and fewer integrations
    Visit Gleek Details and reviews
    How this score is calculated
    Editorial fit ×0.363
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.1585
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Gleek a good PlantUML alternative?

    Verified facts

    4 of 4 verified
    Free plan limits
    5 diagram files, 40 objects
    Checked Oct 25, 2026gleek.io(opens source in a new tab)
    Premium price
    €6.95 per month
    Checked Oct 25, 2026gleek.io(opens source in a new tab)
    Free trial
    None
    Checked Oct 25, 2026gleek.io(opens source in a new tab)
    Input
    Text in Gleek's own syntax
    Checked Oct 25, 2026gleek.io(opens source in a new tab)

The best PlantUML alternative for…

The highest-ranked app in this list for each need.

Mermaid logo

Best PlantUML alternative for most people

Mermaid

Simpler syntax and native rendering on GitHub and GitLab without a server.

D2 logo

Best PlantUML alternative for a free option

D2

Modern text-to-diagram language with nicer default layouts and themes.

Gleek logo

Best PlantUML alternative for a free plan you can upgrade

Gleek

Keyboard-driven text-to-diagram tool in the browser with no setup.

Structurizr logo

Best PlantUML alternative for open source

Structurizr

Better for architecture: one model, many C4 diagrams kept in sync.

Mermaid logo

Best PlantUML alternative for self-hosting

Mermaid

Simpler syntax and native rendering on GitHub and GitLab without a server.

St

Best PlantUML alternative for Mac

StarUML

A visual UML modeller if you'd rather draw than write text.

D2 logo

Best PlantUML alternative for Windows

D2

Modern text-to-diagram language with nicer default layouts and themes.

D2 logo

Best PlantUML alternative for Linux

D2

Modern text-to-diagram language with nicer default layouts and themes.

Mermaid logo

Best PlantUML alternative for working in the browser

Mermaid

Simpler syntax and native rendering on GitHub and GitLab without a server.

PlantUML alternatives: common questions

What is the best alternative to PlantUML?

Mermaid ranks first right now. Simpler syntax and native rendering on GitHub and GitLab without a server. D2 and Structurizr follow it in our ranking.

Is there a free alternative to PlantUML?

Yes. Mermaid (open source), D2 (open source), Structurizr (open source) and Gleek (free plan + paid) have a free option. Check each app's verified facts for current plan limits.

Is there an open-source alternative to PlantUML?

Yes: Mermaid, D2 and Structurizr. Mermaid and Structurizr can also be self-hosted.

Which PlantUML alternatives work on Linux?

D2 and StarUML run on Linux.

Why do people switch from PlantUML?

The complaints we hear most: default visual style looks dated; local use needs Java installed; syntax has many inconsistencies between diagram types.

How is this list ranked?

Every app is scored with the same published formula: how directly it replaces PlantUML, reviews (weighted by verification), visits from AppBreakup, how recently its facts were checked against its own website, and reader votes.