How do I make a sequence diagram?

List your actors (User, Service, Database, etc.), write the messages in order, note any return values, and mention loops or alt branches. Paste that into Figviz, pick a style, and click Generate. The diagram appears in seconds. Refine the prompt if any step is missing and regenerate.

Yes. Every Figviz account starts with free credits you can use to generate sequence diagrams straight away. Buying a pay-as-you-go credit pack removes the watermark and unlocks higher resolutions. Credits never expire.

What are lifelines and activation bars?

Lifelines are the vertical dashed lines in a sequence diagram that represent each actor or system over time. Activation bars are the narrow rectangles drawn on a lifeline to show the period when that actor is actively processing a request. Together they make it easy to see who is busy at any moment in the interaction.

Can it show loops and alt fragments?

Yes. Mention the fragment type in your prompt (for example "show a loop that retries up to three times" or "add an alt fragment for success and failure branches") and Figviz will include the labeled fragment box around the relevant section of the diagram.

Can I use it for software documentation?

Yes. Sequence diagrams generated by Figviz are ideal for API references, design docs, architecture decision records, and runbooks. Export at up to 4K resolution for crisp diagrams in Confluence, Notion, Figma, Miro, or printed materials. Diagrams from a paid account can be used in your own commercial projects and client deliverables.

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Sequence Diagram Generator Sequence Diagrams

Describe an interaction and get a clean, labeled UML sequence diagram in seconds, complete with vertical lifelines, horizontal message arrows, activation bars, and loop or alt fragments. Document software flows without touching a diagramming tool.

✓Lifelines and activation bars✓Loops, alt, and opt fragments✓Request and return arrows✓Slide and doc readyLast updated: 2026-06-21

Sequence Diagram Examples

Browse sequence diagrams made with Figviz, or generate your own above

User Login Authentication

A login flow showing the User, Browser, Auth Server, and Database exchanging credentials and returning a JWT token.

authenticationloginJWT

Online Payment Checkout

A checkout sequence covering the Customer, Frontend, Payment Gateway, and Order Service with confirmation steps.

paymentcheckoute-commerce

API Request-Response

A REST API call chain from Client through API Gateway to Microservice and back, with status codes labeled.

APIRESTmicroservice

E-Commerce Order Placement

An order placement flow across Customer, Cart Service, Inventory Service, and Shipping Service.

orderinventoryshipping

Loop and Alt Fragments

A sequence demonstrating loop and alt combined fragments for retry logic and conditional branching.

loopaltfragments

Simple Two-Actor Sequence

A clean two-actor sequence diagram showing the core UML elements: lifelines, messages, and activation bars.

basiclifelinestwo-actor

Sequence diagram prompts you can copy

Start with a common interaction flow, then replace the actors and messages with your own system details.

Password reset flow

A user-facing journey with an expiring token and a conditional error branch.

Create a UML sequence diagram for a password reset flow. Actors: User, Web App, Auth API, Email Service, Database. Flow: User requests reset, Web App sends email address to Auth API, Auth API checks Database, creates a one-time token, asks Email Service to send a reset link, then returns confirmation. In an alt fragment, show unknown email returning a generic confirmation without sending a link. Show lifelines, activation bars, solid request arrows, dashed returns, and message labels. White background.

File upload with virus scan

A service flow with asynchronous processing and a status callback.

Create a UML sequence diagram for a document upload with virus scanning. Actors: User, Browser, Upload API, Object Storage, Scan Worker, Notification Service. Flow: Browser uploads a file to Upload API, API stores it in Object Storage and queues Scan Worker, worker scans the file, then an alt fragment shows [clean] marking it available and notifying User versus [infected] quarantining it and notifying User. Include asynchronous arrows for queued work, activation bars, and dashed return messages. Classic UML style, white background.

Inventory reservation retry

A purchase flow that uses loop and alt fragments.

Create a UML sequence diagram for inventory reservation during checkout. Actors: Checkout Service, Inventory Service, Database, Payment Service. Checkout Service tries to reserve stock. Use a loop fragment for up to 3 database retry attempts after a conflict. Use an alt fragment: [stock reserved] charge Payment Service and return order confirmation; [out of stock] release any reservation and return an unavailable message. Show all lifelines, activation bars, request arrows, and return arrows. White background.

What is a sequence diagram generator?

A sequence diagram generator is a tool that turns a written description of an interaction into a formal UML sequence diagram. You describe the actors (people, services, or systems) and the messages they exchange, and the tool draws the vertical lifelines, horizontal arrows, and activation bars that make the flow readable at a glance. Figviz uses AI to interpret plain language, so you can describe a login flow, an API call chain, or a checkout process without writing any diagram syntax. The result is a clean, export-ready diagram in seconds.

How to make a sequence diagram

List the actors or systems involved (for example: User, Browser, Auth Server, Database).

Write the messages in order, from the first trigger to the final response.

Note any return values, HTTP status codes, or data passed back.

Mention loops, alt branches, or opt blocks if the flow has conditions or retries.

Choose a style (Classic, Colorful, or Minimal) and generate.

Refine the prompt if any step is missing or out of order, then export.

Sequence diagram elements: lifelines, messages, activation bars, and fragments

Lifelines: vertical dashed lines that represent each actor or system for the duration of the interaction.

Messages: horizontal solid arrows showing a call or signal sent from one lifeline to another, labeled with the operation name.

Return arrows: dashed horizontal arrows showing the response or return value flowing back.

Activation bars: narrow rectangles on a lifeline showing when that actor is actively processing.

Combined fragments: labeled boxes around a section of the diagram to show loops (loop), conditional branches (alt), optional steps (opt), or parallel flows (par).

Self-messages: arrows that loop back to the same lifeline, showing an internal operation or recursive call.

Tips for clear sequence diagrams

Keep actor names short and consistent between the description and the diagram. Always write messages in chronological order top to bottom, the way a reader follows the diagram. Specify return values explicitly (for example "returns 200 OK with JSON") so the dashed arrow gets a useful label rather than a generic one. If a section repeats or branches, name the fragment type (loop, alt) and its condition in your prompt. For large flows, break them into sub-flows and generate one diagram per scenario rather than one giant diagram that is hard to read.

Sequence diagrams in software documentation

Sequence diagrams are a standard part of software design docs, API references, and architecture decision records. They communicate the runtime behavior of a system in a way that static class diagrams cannot: you can see the order of calls, who is waiting on whom, and where the critical path runs. Figviz lets you generate a diagram directly from a plain prose description of a feature, which makes it easy to keep docs in sync with the system as it evolves. Export at 4K resolution for crisp rendering in Confluence, Notion, Figma, or printed runbooks.

Frequently asked questions

A sequence diagram generator is a tool that creates a UML sequence diagram from a description of an interaction. With Figviz you describe the actors and the messages they exchange, and the AI draws the lifelines, arrows, activation bars, and fragment boxes, so you get a finished diagram without writing code or using a drag-and-drop editor.

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