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Best Free Online Tool for Uml Diagrams

A UML diagram is a great visualization and communication tool. It shows how all the components in a system and their relationships and collaborations and dynamic and behavioral processes (like the nouns and verbs in English). Although there are some good free programs for creating UML diagrams, but these tools are usually designed for developers.

Below are the list of great tools designed to make you more productive.

Visual Paradigm

Score: 4.1 / 5

Pricing: Free; $4 for a starter plan; $9 for advanced

UML diagram creator

Another intuitive and powerful UML diagram software is Visual Paradigm. You can save time and effort by choosing from one of its built-in temples to get started. Another interesting feature is that it shows you the editing components whenever you hover over the interface. Visual Paradigm is an integrated software platform that accelerates the development of applications and solutions. It provides a set of tools for visual modeling and data-driven business processes. Visual Paradigm supports multiple languages, platforms and databases for faster development of business applications.


Umple is an open-source modeling tool for software developers and students to make UML in the fastest way in their classroom. Its works online as an eclipse plugin and as a stand-alone command-line Jar.

Umple is an open-source modeling tool that can be used to create and document business processes, systems, and other organizational structures. It’s a higher-level language than many of its competitors, so it’s useful for those who have a background in programming or are interested in learning how to code.

Umple is written in Java, so it runs on any operating system that supports Java 1.8+. This means you can use Umple on Windows, Mac OS X, Linux, Solaris, and more!

Umpledocs is an online documentation tool built specifically for Umple developers. It allows you to create documentation with rich text formatting and use different stylesheets based on the type of content being displayed (e.g., class description or method signature).

Umple is a model-oriented programming technology that adds UML associations and state machines to Java and PHP. It is used to draw UML diagrams, embeds models in code, and generate a complete system.

It is licensed under MIT license.


  1. Simple
  2. UmpleOnline has been very stable.
  3. It makes you model in UML textually.
  4. saves time
  5. You can generate top quality code from class diagrams and state diagrams
  6. You can add a little bit of Umple code into an existing Java, PHP, or Ruby system
  7. Umple works like a pre-processor
  8. You can add just a small sprinkling of Umple into your code


UMLet is an open-source UML tool with a simpler user interface for fast UML diagrams.

UMLet is a free, open-source collaborative writing software. The software allows users to create documents together, in real time, from their computers or mobile devices.

UMLet supports multiple languages and writing formats, including Markdown and LaTeX. It also features an integrated file manager, allowing users to easily move files between their computer and the UMLet server.

It is licensed under GPL-3.0 License and written in JavaScript and Java. It runs stand-alone or as an Eclipse plug-in on Windows, OS X, and Linux.


  1. Draw UML diagrams fast
  2. Export diagrams to eps, pdf, jpg, SVG, and clipboard
  3. Share diagrams using Eclipse
  4. Create new, custom UML elements
  5. Build sequence and activity diagrams from plain text


UML Tools

Whitestar UML is a division of StarUML 5.0 that offers bug fixes and has improved its compatibility with the latest operating systems, i.e., support of Unicode strings or simply being developed and tested on Windows 7 and 8.

WhitestarUML is a free, open-source UML tool for Windows. The program allows you to create UML diagrams, validate them, and export them as image files or XML.

WhitestarUML supports:

  • Classes and associations
  • Generalization, specialization and aggregation relationships
  • Role/interaction/use cases
  • State machines


  • It offers a refreshed user interface.
  • It completely handles the functioning of Unicode strings.
  • It provides support on Windows 7, 8, and 10.
  • On-demand upload and download of units.
  • It directly integrates the ERD profile and extends to generate and parse the SQL tables.

Download link:


Modelio is an open-source collaborative Business, software modeling environment that is used by code developers, business architects, software architects, system architects, workgroups, and analysts.

It has a flexible extension mechanism with modules, a wide range of existing modules, and you can develop your own modules.

It is licensed under the GPL v3 license.

Modelio is a modeling tool that helps you build and maintain complex models. It provides a graphical user interface that enables you to create and manipulate models, and allows you to execute the model quickly with the click of a button.

Modelio supports many different types of models including:

• Discrete event

• Flow chart

• Process flow diagram

• Dataflow diagram


  1. Simple UML Modeler interface
  2. BPMN support integrated with UML
  3. Java code generator
  4. XMI import/export
  5. HTML model publishing
  6. Extension system
  7. Scripting language support (Jython)
  8. Workgroup
  9. Federated repositories and Portfolio Management
  10. Document generation
  11. Requirement Analysis integrated with models
  12. Code generation (C++, C#, Java, SQL, …)
  13. TOGAF, UPDM, SysML,
  14. Web Analyst: Web-based requirement analysis integrated with Modelio is an open-source technology, a professional diagramming tool for building diagramming applications. is an online drawing tool that allows you to create diagrams, flowcharts, and more. You can also export your work as PDF files, PNG images, or even SVG files. In addition to creating diagrams, you can import images and text into your diagram and change the color of objects.

The interface is simple enough for anyone to figure out how to use it but still has some advanced features such as exporting in SVG format. There is also a built-in chat feature so you can communicate with other users while working on your project.

With it you can share your diagrams with everyone, it comes with powerful features.

It is licensed under Apache-2.0 License and written in JavaScript.


  1. you can export images of diagrams directly from the lightbox viewer
  2. Move shapes forwards and backward on the drawing canvas
  3. An online whiteboard for Confluence with
  4. It comes with template diagrams with previews, subcategories, and search
  5. Draw freehand shapes and annotate diagrams
  6. Embed diagrams in PowerPoint
  7. Use with Google Classroom
  8. Create an interactive diagram and toggle layers with custom links
  9. Embed diagrams into Notion from
  10. Insert a diagram from specially formatted CSV data


JetUML is an open-source UML desktop application for creating and editing diagrams. It is support sketching, available both as a self-contained application and as a Java archive file. JetUML is a software tool for creating UML diagrams. It is written in Java, and it features a drag-and-drop interface, which makes it very easy to use. JetUML also supports reverse engineering of code in various programming languages, so that you can create diagrams from code.

It is licensed under GPL-3.0 License and written in Java.


  1. Diagrams can be saved in JSON
  2. Lightweight
  3. you can export to popular image formats
  4. It has the ability of copied to the system clipboard for integration with other tools
  5. It supports class diagrams, sequence diagrams, state diagrams, object diagrams, and use case diagrams


PlantUML is an open-source component that allows you to write a sequence diagram, use case diagram, class diagram, activity diagram, component diagram, state diagram, object diagram, deployment diagram, timing diagra

m, and more.

It also supports a wireframe graphical interface, JSON, and YAML data, network diagram, archimate diagram, entity relationship diagram, and more.

it is license under GPL license and written in Java.


  1. it generates a UML diagram from textual description
  2. Images can be generated in PNG, SVG, Latex format
  3. you can install PlantUML locally
  4. you can run it from the command line


StarUML is a software modeler for agile and concepts modeling for macOS windows and different types of Linux(Ubuntu, Debian, Redhat, fedora).

it is support code generation for various programming languages such as Java, C#, C++, and python, it also has Open APIs

It is licensed under MIT license.


  1. Compatible with UML 2.x
  2. Support modeling with SysML diagrams
  3. Cross-Platform Support
  4. Auto Update
  5. Retina Display Support
  6. Extension Manager
  7. Model-Driven Development
  8. The data are stored in a very simple JSON format,
  9. Fast Modeling
  10. Dark and Light Themes
  11. Command Palette
  12. PDF Export for Clean Printing
  13. It supports Markdown language


Dia Diagram Editor

Dia is an open-source program use to draw structured diagrams. With it, you can draw many shapes like UML, flow chart, and more.

Dia is free software released under the GPLv2, and you can download it in windows, Linux, and macOS.


UML Tools

GenMyModel is an online modeling platform that offers Business (Archimate, BPMN, flowcharts support) as well as IT modeling (RDS, UML2.5 class diagrams).


  • It provides an online platform.
  • It generates online code.
  • It provides a centralized repository for easy and simultaneous model collaboration.
  • You can import or export as a PDF.

Download link:


UML Tools

It is an online platform that offers UML tools for faster development of UML diagrams. It is based on UMLet, which is an eclipse plugin or work as a standalone tool.


  • It allows you to export the diagram as XML or any other image file such as Gif, JPEG, or SVG format.
  • It is an installation free web application.

Download link:

Eclipse Papyrus

Eclipse Papyrus is a modeling environment and open-source model-based engineering tool used in industrial projects.

It provides editors for all the UML diagrams (Class Diagram, Object Diagram, Package Diagram, Composite Structure Diagram, Component Diagram, Deployment Diagram, Profile Diagram, Use case Diagram, and more).


  1. Graphical editing tool for UML 2
  2. Fully customizable environment
  3. Define your own graphical, textual or tabular notation.
  4. Filter existing palettes or define your own ones
  5. Support SysML
  6. Real-time Systems modeling.
  7. It has a set of tools for integrating safety techniques


Diagramo is an online flowchart software, it makes your work easier.

It comes with a built-in editor and user-friendly features:


  1. It is FREE and Open Source
  2. It’s pure HTML5
  3. With it, you can share and collaborate
  4. Export to PNG, Gif, and JPEG
  5. You can download it and deploy it on your server
  6. Customizable



Open-source UML and SysML Modeling Application For Windows, Linux, and macOS.

Gaphor is a UML and SysML modeling application written in Python and license under the Apache-2.0 license.


  1. simple stacked user-interface
  2. It comes with a drag-and-drop functionality
  3. It allows the developers to quality visualize highly complex models.
  4. Lightweight
  5. Class support
  6. Export to SVG, PDF, PNG, and XMI
  7. Alignment and snapping option

Open ModelSphere

Open ModelSphere

Open ModelSphere is free software  Modeling Tools Available as open-source software released under GPL.



16 Popular Free And Open Source UML tools

Umletino is a free, web-based, stand-alone UML tool. It is a fast tool it is aimed to create uml sketches in the fastest way.


  1. Simple
  2. Fast
  3. markup-based element edits
  4. mouse-controlled overall layout design
  5. Drag and Drop tool



Archi is an open-source software architecture model, modeling toolkit to create the business, IT, and software architecture models using the ArchiMate modeling language.


  1. Contextual menus
  2. mouse-over descriptions of symbols
  3. hint window to relate your current work
  4. You will be prevented to create impossible relationships between diagram items.
  5. Easy to use
  6. Intuitive diagramming tool
  7. More than one model can be open at once
  8. You can lock elements of the diagram to avoid unwanted changes
  9. Elements can be grouped in a view using a group container type



ArgoUML is an open-source developer tool that is used for development purposes to help in creating diagrams, so easily can visualize projects that they intend to develop and deploy.


  1. Supports decision making
  2. Simplifies the modeling process
  3. It supports OCL, SVG, and XMI and can run on any Java platform.
  4. It is Compliant with UML 1.1
  5. It doesn’t support UML 2.0
  6. provide cognitive backing via its modeling structure


Using this software you can create a complete UML model without any cost, within a few minutes. It is easy to use and I’ve been using it for creating my own diagrams. All the templates are already created which makes it very simple to start using it. Although it is considered as an open source product, the company LucidCharts presents it in such a way that they make you buy their premium version if you want to make some changes to the diagrams or add them to your documents.

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