Communication diagram maker

No matter the kind of communication diagram you have in mind, our UML diagram tool can help you get to work on it right away, with diagram specific shape libraries to get you started.

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See the Architecture, Not Just the Order

Creating a communication diagram is like drawing a map of a neighborhood and then tracing the routes of the mail carriers. It’s less about "when" things happen and more about "who" talks to whom.

Visualizes Structural Relationships

Unlike other interaction diagrams, this one excels at showing how objects are physically or logically linked. It’s essentially an Object Diagram with "traffic" (messages) drawn on top of it, making it clear which objects are central to the system's architecture

Collaborate in real time

Invite people to view, edit, or give real-time feedback on your UML diagram using comments and @mentions. Review individual contributions by enabling collaborator colors, and use revision history to see changes or revert to a previous version.

Built-in UML diagram shape library

Our shape library has what you need for your Communication diagrams. Our shape library includes all the symbols and notation similar to Sequence diagrams. With our Communication diagram creator, you can make your diagrams look professional and build them with best practices in mind.

Get an easy-to-use UML diagram with templates

Start with a template or build your diagram from scratch using UML shapes in Lucidchart’s shape library. Link data within your diagram from spreadsheets or add formulas to reference parent-child relationships between shapes.

Boost productivity with 100+ integrations

Connect Lucidchart to apps from leading providers like Google, Microsoft, and Slack. Explore the Lucid integrations marketplace for apps to streamline communication, strategic planning, task management, and more.

Lucidchart feature highlights

Real-time collaboration

Streamline work by enabling multiple collaborators to create and edit the same diagram at once.

Data linking

Create accurate diagrams faster by linking shapes to data from Google Sheets, Excel, or CSV files.

Conditional formatting

Transform data by visually highlighting patterns and insights for quick comprehension at a glance.

Layers

Add layers to visualizations for multiple levels, distinct visibility controls, and streamlined editing.

Revision history

Collaborate confidently—view changes, revert to prior versions, and ensure diagrams are up to date.

Shape libraries

Use existing shape libraries for Salesforce, enterprise architecture, and more—or customize your own.

AI prompt flow

Build and experiment with LLMs on the Lucid canvas. Test prompts and inputs to see what works best.

Lucidchart feature highlights

Streamline work by enabling multiple collaborators to create and edit the same diagram at once.

UML diagram templates and examples

Use a template from our gallery to get a head start on your UML diagram.

Activity diagram with swimlanes

Go to Activity diagram with swimlanes template

UML class diagram

Go to UML class diagram template

Web sequence diagram

Go to Web sequence diagram template

Getting started in Lucidchart

Getting Started in Lucidchart

Follow along with this video tutorial and learn how to make any type of diagram in Lucidchart.

Make a diagram

Why teams choose Lucidchart

As an intelligent diagramming application, Lucidchart provides simple yet powerful capabilities for visualizing information.

Collaboration. Bring teams together side by side on a shared canvas from anywhere in the world.

Alignment. Build transparency and shared understanding of how a team or company works.

Large-scale change. Increase visibility, standardization, and knowledge sharing across your entire org.

End-to-end workflows. Upgrade to the Lucid Suite for a complete, connected visual collaboration solution.

What is a UML Communication diagram?

A communication diagram offers the same information as a sequence diagram, but while a sequence diagram emphasizes the time and order of events, a communication diagram emphasizes the messages exchanged between objects in an application. Sequence diagrams can fall short of offering the "big picture.” This is where communication diagrams come in and offer that broader perspective within a process.

How to create a UML Communication diagram

Identify the Context and Participants

Start by defining the specific use case or operation you want to model. Once the scope is set, identify the objects (instances of classes) and actors (external users or systems) involved in that specific scenario.

Establish the Structural Links

Draw lines (links) between the objects that need to communicate. A link indicates that a relationship exists between two objects, allowing them to send messages to one another.

Add Messages and Direction

Define the messages (methods or signals) that pass between the objects. For each message, draw a small arrow pointing in the direction of the communication flow next to the link.

Apply Sequence Numbering

Since there is no vertical timeline, you must use decimal numbering (e.g., 1, 1.1, 1.2, 2) to indicate the order of operations.

1: The initial trigger message.
2: The first nested message sent by the receiver of message 1.
3: The next top-level message.

Refine with Iteration and Loops (Optional)

Add details like guards or iteration markers to show complex logic. Review the diagram to ensure it accurately represents the collaboration without becoming a "spaghetti" of crossing lines.

Additional Lucidchart resources

Lucid Training Labs

Learn visual collaboration skills in free, self-serve courses and live training workshops.

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Lucid Community

Connect with other users to share tips and insights. Provide feedback to Lucid’s product team.

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Help center

Find detailed articles with step-by-step instructions for using specific Lucid features.

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Lucidchart tutorials

Go to the Lucidchart tutorials playlist on YouTube for video training on various topics.

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Collaborate with AI

Get an overview of Lucid’s AI functionality and find additional resources.

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Lucid blog

Explore tips for optimizing collaboration, aligning teams, and driving initiatives in Lucidspark.

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Lucidchart pricing

Create a free account and compare options for paid Individual, Team, or Enterprise plans.

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Frequently asked questions about UML diagrams

Can I build a UML diagram using markup?

Yes. First, you will need to enable the UML sequence diagram shape library. Then, Lucidchart provides a UML sequence markup feature that auto-generates a sequence diagram based on the text you provide.

How can I change the formatting of a UML diagram?

You can add styling and formatting to your UML diagram using the Properties bar at the top of the Lucidchart editor.

Can I show the difference between current and future states within the UML diagram?

Yes, use the layers feature to visualize current, ideal, or future states of any process or system side by side. Start with your current system and then create a layer depicting future states. Use hotspots to toggle between layers.

Learn more

What are the options for sharing my UML diagram in Lucidchart?

Publish and share diagrams with Lucidchart users and non-users via email, shared link, PDF, or image file. You can also share your diagram on social media or embed it onto any webpage.

Everything you need to make a diagram

In addition to our online communication diagram tool, Lucidchart offers support and training resources to help you branch out to any type of diagram.

Lucid Training