Top 10 Open Source Alternatives to PlantUML in 2025

PlantUML has long been a go-to tool for creating UML diagrams from plain text. However, the fast-evolving landscape of open-source software has introduced several powerful alternatives. Whether you're looking for more features, easier integration, or simply a different approach, this article explores the top 10 open-source alternatives to PlantUML in 2025.

Boost Your SEO by Getting Featured in Our Blogs and get a backlink.

We publish content about startups, education, tech, funding, etc. that ranks well not only in Google but also in Perplexity, ChatGPT, Grok and other AI tools.

👉 Get featured now!

1. Mermaid

Description: Mermaid is a JavaScript-based diagramming and charting tool that uses a markdown-like syntax to generate diagrams. It's highly popular for its ease of integration and wide variety of supported diagram types.
Key Features:
Text-based diagram creation.
Supports various diagram types (flowcharts, sequence diagrams, Gantt charts, etc.).
Easy to embed in websites.
Live editor and preview.
Active community and frequent updates.
Website: Mermaid
Source: Mermaid GitHub
Data Source: [3, 8, 14, 21]

2. Draw.io (Diagrams.net)

Description: Draw.io, now known as diagrams.net, is an open-source diagramming application that offers both online and offline functionality. It's favored for its user-friendly interface and extensive library of templates.
Key Features:
Drag-and-drop interface.
Extensive library of shapes and templates.
Real-time collaboration.
Integration with various platforms (Google Drive, GitHub, etc.).
Supports many diagram types (UML, flowcharts, mind maps, etc.).
Website: Draw.io
Source: Draw.io GitHub
Data Source: [1, 3, 7, 10, 11, 14, 18]

Get your FREE Landing Page Analysis!

Insert your landing page link and get a super useful analysis and easy fixes to get more clicks!

👉 Get Your Analysis Here!

3. Kroki

Description: Kroki is an integrative service that generates diagrams from various text-based diagram languages, making it highly versatile for different use cases.
Key Features:
Supports multiple diagram languages.
Generates diagrams server-side.
Easy to integrate.
Supports various output formats (PNG, SVG, PDF, etc.).
Can be self-hosted.
Website: Kroki
Source: Kroki GitHub
Data Source: [3]

4. ArgoUML

Description: ArgoUML is a classic UML modeling tool providing comprehensive support for UML 1.4 diagrams, suitable for both straightforward and complex projects.
Key Features:
Supports all UML 1.4 diagrams.
Code generation in multiple programming languages.
Reverse engineering capabilities.
Project management features.
Runs on any platform with Java.
Website: ArgoUML
Source: ArgoUML SourceForge
Data Source: [4, 15]

5. StarUML

Description: StarUML is a sophisticated UML modeling tool designed for professional software modeling with support for numerous UML diagrams and extensions.
Key Features:
Supports multiple UML diagrams.
Drag-and-drop interface.
Extensions and customization options.
Visual modeling and code generation.
Integration libraries.
Website: StarUML
Source: StarUML SourceForge
Data Source: [4, 12]

Validate your startup idea with the unique borrowed authority approach: we publish articles about your product in our blog and you get traffic and testers for your MVP

Prove Market Demand: See real organic traffic and waitlist conversions

Unlock High-Potential Keywords: Receive a curated list of top-performing keywords directly from Google Search Console data.

Estimate Customer Acquisition Cost (CAC): Gain financial foresight with an estimated CAC based on real keyword performance data.

🔗 Start validating your startup now

6. Eclipse Papyrus

Description: Part of the Eclipse ecosystem, Eclipse Papyrus supports UML and other modeling languages, providing extensive features for model-driven development.
Key Features:
Supports UML and other modeling languages.
Customizable interface.
Model-driven development support.
Rich set of modeling features.
Part of the Eclipse ecosystem.
Website: Eclipse Papyrus
Source: Eclipse Papyrus GitHub
Data Source: [4, 12]

7. Modelio

Description: Modelio is a versatile modeling environment supporting UML, BPMN, and other standards, known for its extensibility and integration capabilities.
Key Features:
Supports UML and BPMN modeling.
Extensible with custom modules.
Integration with programming languages.
Comprehensive set of modeling tools.
Support for various modeling standards.
Website: Modelio
Source: Modelio GitHub
Data Source: [4]

8. Inkscape

Description: Inkscape is a renowned open-source vector graphics editor that can be used for creating a wide variety of diagrams, despite not being a dedicated diagramming tool.
Key Features:
Vector graphics editor.
Drawing tools (pencil, pen, shapes).
3D boxes tool for quick drawing.
Custom brushes, layers, paint tools.
Used across various industries.
Website: Inkscape
Source: Inkscape GitHub
Data Source: [6]

9. D2

Description: D2 is a modern text-to-diagram language known for its clean syntax and readability, designed to create diagrams from code easily.
Key Features:
Text-based diagram creation.
Clean and readable syntax.
Live playground for testing without installation.
Designed for code-like expressiveness.
Supports various diagram types.
Website: D2
Source: D2 GitHub
Data Source: [24]

10. ZenUML

Description: ZenUML offers an intuitive interface for creating sequence diagrams with real-time updates and HTML DOM based rendering.
Key Features:
Real-time updates to diagrams.
Intuitive interface and gentle learning curve.
HTML DOM based rendering.
Image conversion support through a chrome extension.
Searchable diagram content.
Website: ZenUML
Data Source: [17]

These tools offer a variety of options for replacing PlantUML, ranging from simple diagram creation tools to comprehensive UML modeling environments. Each listing includes the tool’s description, key features, and direct links to the website and source code to help you make an informed choice for your needs.

Join ElonaHunt (like ProductHunt but for women) and explore the coolest women-focused startups out there!

Discover your next big inspiration and connect with like-minded female entrepreneurs!

👉 Join the Hunt Here

FAQ

1. What is Mermaid used for?

Mermaid is a JavaScript-based diagramming and charting tool that uses a markdown-like syntax to generate diagrams, making it easy to integrate into web pages and documentation. Learn more about Mermaid

2. What features does Draw.io (Diagrams.net) offer?

Draw.io (Diagrams.net) is known for its user-friendly drag-and-drop interface, extensive library of shapes and templates, real-time collaboration, and integration with platforms like Google Drive and GitHub. Explore Draw.io (Diagrams.net)

3. Can Kroki generate diagrams from multiple languages?

Yes, Kroki supports multiple text-based diagram languages including PlantUML and Mermaid, and can generate diagrams in various output formats such as PNG, SVG, and PDF. Discover Kroki

4. What standard does ArgoUML support?

ArgoUML supports all UML 1.4 diagrams and offers features like code generation, reverse engineering, and project management. Learn more about ArgoUML

5. Does StarUML support extensions?

Yes, StarUML supports extensions and customization, making it flexible for visual modeling and code generation. Explore StarUML

6. What modeling languages does Eclipse Papyrus support?

Eclipse Papyrus supports UML and various other modeling languages and offers a customizable interface for model-driven development. Learn more about Eclipse Papyrus

7. What capabilities does Modelio provide?

Modelio is an extensible open-source modeling environment supporting UML and BPMN modeling with integration capabilities for various programming languages. Discover Modelio

8. Can Inkscape be used for diagrams?

Yes, Inkscape is a versatile vector graphics editor that, while not specifically for diagrams, can be used to create a wide range of diagrams, flowcharts, and illustrations. Learn more about Inkscape

9. What is D2's focus in diagram creation?

D2 is a modern text-to-diagram language focused on clean syntax and readability, designed for code-like expressiveness and supporting various diagram types. Explore D2

10. What types of diagrams can ZenUML create?

ZenUML is designed specifically for creating sequence diagrams, featuring real-time updates, an intuitive interface, and HTML DOM based rendering for styling customization. Learn more about ZenUML

References

About the Author

Violetta Bonenkamp, also known as MeanCEO, is an experienced startup founder with an impressive educational background including an MBA and four other higher education degrees. She has over 20 years of work experience across multiple countries, including 5 years as a solopreneur and serial entrepreneur. She’s been living, studying and working in many countries around the globe and her extensive multicultural experience has influenced her immensely.

Violetta is a true multiple specialist who has built expertise in Linguistics, Education, Business Management, Blockchain, Entrepreneurship, Intellectual Property, Game Design, AI, SEO, Digital Marketing, cyber security and zero code automations. Her extensive educational journey includes a Master of Arts in Linguistics and Education, an Advanced Master in Linguistics from Belgium (2006-2007), an MBA from Blekinge Institute of Technology in Sweden (2006-2008), and an Erasmus Mundus joint program European Master of Higher Education from universities in Norway, Finland, and Portugal (2009).

She is the founder of Fe/male Switch, a startup game that encourages women to enter STEM fields, and also leads CADChain, and multiple other projects like the Directory of 1,000 Startup Cities with a proprietary MeanCEO Index that ranks cities for female entrepreneurs. Violetta created the "gamepreneurship" methodology, which forms the scientific basis of her startup game. She also builds a lot of SEO tools for startups. Her achievements include being named one of the top 100 women in Europe by EU Startups in 2022 and being nominated for Impact Person of the year at the Dutch Blockchain Week. She is an author with Sifted and a speaker at different Universities. Recently she published a book on Startup Idea Validation the right way: from zero to first customers and beyond and launched a Directory of 1,500+ websites for startups to list themselves in order to gain traction and build backlinks.

For the past several years Violetta has been living between the Netherlands and Malta, while also regularly traveling to different destinations around the globe, usually due to her entrepreneurial activities. This has led her to start writing about different locations and amenities from the POV of an entrepreneur. Here’s her recent article about the best hotels in Italy to work from.

About the Publication

Fe/male Switch is an innovative startup platform designed to empower women entrepreneurs through an immersive, game-like experience. Founded in 2020 during the pandemic "without any funding and without any code," this non-profit initiative has evolved into a comprehensive educational tool for aspiring female entrepreneurs.The platform was co-founded by Violetta Shishkina-Bonenkamp, who serves as CEO and one of the lead authors of the Startup News branch.

Mission and Purpose

Fe/male Switch Foundation was created to address the gender gap in the tech and entrepreneurship space. The platform aims to skill-up future female tech leaders and empower them to create resilient and innovative tech startups through what they call "gamepreneurship". By putting players in a virtual startup village where they must survive and thrive, the startup game allows women to test their entrepreneurial abilities without financial risk.

Key Features

The platform offers a unique blend of news, resources,learning, networking, and practical application within a supportive, female-focused environment:

Skill Lab: Micro-modules covering essential startup skills
Virtual Startup Building: Create or join startups and tackle real-world challenges
AI Co-founder (PlayPal): Guides users through the startup process
SANDBOX: A testing environment for idea validation before launch
Wellness Integration: Virtual activities to balance work and self-care
Marketplace: Buy or sell expert sessions and tutorials

Impact and Growth

Since its inception, Fe/male Switch has shown impressive growth:

3,000+ female entrepreneurs in the community
100+ startup tools built
5,000+ pieces of articles and news written

Partnerships

Fe/male Switch has formed strategic partnerships to enhance its offerings. In January 2022, it teamed up with global website builder Tilda to provide free access to website building tools and mentorship services for Fe/male Switch participants.

Recognition

Fe/male Switch has received media attention for its innovative approach to closing the gender gap in tech entrepreneurship. The platform has been featured in various publications highlighting its unique "play to learn and earn" model.