drawioseq

Generate draw.io sequence diagrams from plain-text .seq files — automatically on every save.

Write this:

title: Order Flow

participant Client
participant Server
participant DB

activate Client

Client ->+ Server: POST /order
Server ->+ DB: INSERT order
DB -->>- Server: ok
Server -->>- Client: 201 Created

deactivate Client

Get this → a fully editable .drawio file next to your .seq file, ready to open in draw.io or the Draw.io Integration VS Code extension.

Features

• Auto-generates foo.drawio alongside foo.seq on every save
• Manual trigger via Command Palette: drawioseq: Generate .drawio from current .seq file
• Status bar indicator shows generation progress and result
• Helpful errors — if lark is not installed, the extension tells you exactly what to run
• Powered by drawio-seqgen (vendored, no external calls)

Requirements

Python 3 must be installed and available on your PATH as python3 or python.

The lark parsing library must also be installed:

pip3 install lark

The extension will show an error with this command if lark is missing.

Syntax

One statement per line. Comments start with //.

Participants

participant Alice
participant J: John         // with display label
participant Big width 250: Big Box

Messages

Alice -> Bob: Hello!           // solid arrow
Alice --> Bob: dashed
Alice ->>+ Bob: activate Bob
Bob -->>- Alice: deactivate Bob
Alice ->| Bob: fire and forget
Alice -> Alice: self call
Alice: shorthand self call

Frames

opt condition
  Alice -> Bob: maybe
end

alt x == 1
  Alice -> Bob: yes
else
  Alice -> Bob: no
end

loop until done
  Alice -> Bob: again
end

Other

title: My Diagram
activate Alice
deactivate Alice
note on Alice: some note
vertical offset 30

Full syntax reference: drawio-seqgen

Release Notes

0.0.1

Initial release.