Sequence Chart
Sequence Diagram Configuration
Participants
Define the participants (actors or systems) in your sequence diagram. Each participant represents an entity that sends or receives messages.
Participants
Messages
Define the messages exchanged between participants. Messages show the flow of communication and can have different arrow types to indicate synchronous, asynchronous, or return messages.
Messages
Notes
Add notes to provide additional context or explanations in your sequence diagram. Notes can be positioned relative to participants.
Notes
Select one participant for left/right, one or two for over
Select one participant for left/right, one or two for over
Display Settings
Free Online Sequence Chart Maker
What is a Sequence Chart?
A sequence chart (or sequence diagram) shows how participants — people, systems, or services — exchange messages over time in a defined order. It maps the exact flow of communication step by step, making it easy to understand who sends what, when, and to whom. Use it to document system interactions, plan API integrations, or explain multi-step processes to technical and non-technical audiences alike.
Key Features
Participants and Actors
Define systems, services, or people as either box-style participants or stick-figure actors. Each gets its own lifeline running down the diagram.
Multiple Arrow Types
Choose from solid, dotted, async, and cross arrows to precisely represent synchronous calls, return messages, fire-and-forget events, and failures.
Activation Bars
Mark when a participant is actively processing a request with activation and deactivation controls, so processing time is visually clear.
Sequence Numbers
Toggle auto-numbered messages to make diagrams easier to reference in documentation, reviews, or presentations.
Notes and Annotations
Attach notes to the left, right, or spanning over participants to add context, explain decisions, or flag important conditions.
Zoom and Pan
Navigate large, complex diagrams without losing detail using built-in zoom and pan controls.
Best For
When to Use
- When the order of interactions between multiple systems or people matters
- When you need to show who initiates each step and who responds
- When documenting how a feature works across services before or after building it
- When reviewing a process for bottlenecks, redundant calls, or missing error handling
- When aligning engineers and product managers on a shared flow before implementation
Common Mistakes
- !Adding too many participants at once — keep diagrams focused on one flow or scenario
- !Using vague message labels like 'request' instead of specific actions like 'POST /api/login'
- !Skipping activation bars, which hides how long each participant is actively processing
- !Mixing high-level and low-level detail in the same diagram — pick one abstraction layer
- !Omitting error or failure paths, leaving viewers with an incomplete picture of the flow
- !Using only solid arrows for everything instead of choosing arrow types that reflect the interaction style
Related Tools
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