As the saying goes, a picture paints a thousand words. And when it comes to explaining the complexity of software development, this is especially true.
UML (Unified Modelling Language) diagrams are an incredibly effective way to communicate the complex ideas and processes that go into developing new software.
This is essential to ensure that everyone is on the same page before any coding starts.
To draw sequence diagram mockups quickly and effectively however you need the right software. We’ve taken a look at the best UML tools to help you draw fast UML diagrams including free open source apps.
Many of these apps such as the excellent SmartDraw even work on both Mac & PC so this article will also be of interest to Windows users too.
Why UML Modelling Software Is So Important
UML tools allow you to clearly explain software development ideas before any programming is done.
When combined with some decent project management software this saves a lot of time and wasted resources creating something coherent that everyone understands.
This is especially important when trying to communicate ideas to new members of a programming team or inexperienced developers.
The best UML modelling tools allow you to create product mockups quickly, easily and with maximum impact.
It’s important to understand however that UML software is distinct from general diagram software. At the end of the day, UML tools are more about modelling than drawing diagrams and flowcharts.
While many of the best diagram software for Mac can be used for UML, there’s a whole sub-genre of software dedicated to UML modelling because of this.
Important Considerations When Choosing A UML Tool
Here’s a few questions you should consider before choosing which UML tool for Mac to go for.
- Do you need just a UML model or also to draw and create diagrams? Incredibly easy to use and powerful diagramming apps like SmartDraw are multi-purpose as they support both UML drawing but also other tasks such as flowcharts and org charts.
- Do you need support for all 13 classes of UML diagram? Most apps that support UML do but currently that includes class, activity, object, use case, sequence, package, state, component, communication, composite structure, interaction overview, timing, and deployment. These are in-turn divided into 2 different types, Structural UML diagrams and Behavioral Structural Diagrams.
- Is it compatible with that latest UML 2.0 standard? Again, you’ll find that most are but some older open source tools may not be.
- Do you need to just create UML diagrams frequently? If not, there are many free sequence diagram apps that are fine to do the odd job. If you’re going to create UML models frequently however, it’s strongly recommended to pay or subscribe to an app.
- Do you need portability? There are many free open source UML tools that use their own text based input language for diagrams but they require learning their own specific language and commands. Bear in mind there there may also be no way to export them to another format such as XML which you can import into another UML program if you change app later down the line.
- Do you need Visio import support? Although Visio isn’t available for Mac, there are some very good alternatives to Visio on Mac which can import Visio UML diagrams in VSDX format.
With these things in mind, here then is our list of the best UML software for Mac in order of ranking.
Lucidchart is another powerful but user-friendly online diagramming software that makes it easy to make sequence diagrams.
Lucidchart allows you to drag and drop objects, has an extensive shape library and is one of the best UML tools for Mac when it comes to collaboration in a team.
You can export to PDF or instantly to presentation mode for presentation and you can import Visio files.
Note that it does not export to the latest Visio VSDX format though (for that you need SmartDraw).
You can start using Lucidchart for free now although you’ll need to upgrade to a full plan to use more objects, storage space and other features.
You can find more in our full review of Lucidchart.
Star UML is probably the most popular UML software for Mac or PC on the market and is used by big brands like Amazon, IBM and Apple.
Star UML is a sophisticated software modeller for agile and concise modeling or interface realization and offers both a Mac and Windows desktop client.
There are useful touches such as PDF export for printing, HTML publishing and Quick Edits for fast modelling.
You can also extend it with things such as Python, Java and C++ code generator extensions.
Overall, StarUML is easily the best sequence diagram tool we’ve tried and even better, you can use StarUML for free.
Even better, you only need to upgrade if you intend to use it for commercial use with prices starting at $89 for an individual license.
If you’re looking for something that does the hard work for you when it comes to UML design, look no further than SmartDraw.
SmartDraw is about as user-friendly as it gets when it comes to sequence diagrams and even automates the process for you.
SmartDraw has templates for all types of UML diagram which automatically balance and re-balance as you build to keep your diagrams tidy and organized.
It has a huge object library of over 40,000 which is far more than most similar apps. It’s also one of the few UML diagram tools for Mac that can both import and export Visio files in the latest VSDX format.
You can also try a start a UML diagram now SmartDraw for free to see what you think for yourself.
For a more in-depth look, check out our full SmartDraw review.
Visual Paradigm is one of the major competitors to StarUML and is also used by big companies like Adobe, Intel and NASA.
Although its not exclusively for UML design like StarUML, the UML tools are one of it’s strongest features. Visual Paradigm is design object-oriented software idea for Case Diagrams, Class Diagrams and Sequence Diagrams.
There are two versions of Visual Paradigm – the Community Edition which is free and the Commercial Edition. The Community Edition is generous in features and allows unlimited diagrams, project sizes and shapes.
It also includes 13 different types of UML diagram plus ERD diagrams. You can use Visual Paradigm either online or there’s a Mac desktop client too.
Astah is one of the most professional and powerful UML tools out there used by companies ranging from Amazon to Oracle.
Astah is specifically focused on UML software for software development and is extremely popular among IT professionals, consultants and programmers.
The professional version of Astah not only does UML but also supports flowcharts for workflows, brainstorming and mindmapping.
If you want to map out your software ideas quickly, clearly and improve customer satisfaction, Astah is about as good as it gets for software developers.
If you prefer desktop apps over cloud based ones, then OmniGraffle might be for you. OmniGraffle is arguably the best desktop diagram software for Mac with powerful UML tools.
OmniGraffle has a huge number of UML templates and mockups and even if you can’t find what you’re looking for, you probably will in the many community driven resources for OmniGraffle templates.
OmniGraffle can import Visio files and even if you decide not to upgrade to the full version, you can continue to use it as a free desktop Visio viewer.
Check out our full OmniGraffle review for more.
ConceptDraw Diagram (formerly ConceptDraw Pro) is a powerful cross-platform diagramming software which works on both Mac and PC. ConceptDraw Diagram is ideal for project managers as it’s fully integrated with ConceptDraw Project – a powerful alternative to Microsoft Project on Mac. ConceptDraw has all 13 UML stencil libraries with almost 400 vector graphics.
You can see some samples of UML diagrams made with ConceptDraw Diagram here.
You can also check out our full review of ConceptDraw Diagram here.
UMLet is a free open source UML modelling tool with a very simple user interface that’s easy for beginners to use.
The difference between UMLet and other sequence diagram tools is that it allows you to modify diagrams using a text input tool instead of pop-up dialogs.
You can build sequence and activity diagrams from plain text, export to PDF, EPS, JPG and SVG and create your own custom UML elements.
You can watch a brief overview of how to use UMLet below:
PlantUML is another free open source sequence diagram software that uses text input to build UML charts. PlantUML requires using a specific PlantUML Language to construct sequence charts but once learned it’s very flexible.
PlantUML is partciularly good at drawing Usecase diagrams, Class diagrams and activity diagrams.
PlantUML also has a useful Atlassian plugin which allows you to quickly draw UML models in Confluence Cloud.
PlantUML even supports non UML diagrams such as Wireframes, Archimate diagrams and Gantt charts.
It really doesn’t get much simpler than yUML. yUML is a basic free UML software ideal for those that need to embed UML diagrams in blogs, wikis, forums or bug trackers.
Although it’s very simple, yUML has been used by companies as big as Twitter, Bose and Lockheed Martin. yUML is not a visual drawing tool – it work via GET and PUT commands.
It’s very quick and easy to learn and once you’re up and running, you can whip-up sequence diagrams very quickly and conveniently.
We hope we’ve helped you find the right UML tool for your needs.
This top list is by no means an exhaustive look at UML authoring software though. For example, we’ve omitted popular tools such as ArgoUML which require Java because we don’t recommend installing Java on Mac for a number of reasons.
If you have any questions or problems with any of the software featured here, let us know in the comments below.