casen dev — BPMN Kit Docs

casen dev turns a folder of .bpmn, .dmn and .form files into a local development environment. It starts a small web server, opens the BPMN Kit editor in your browser, and re-checks each file every time it changes — whether you saved it in the browser or in another editor.

casen dev              # the current folder
casen dev ./processes  # another folder

  casen dev  /home/me/shop
  UI        http://127.0.0.1:4747/
  files     3 (2 bpmn, 1 dmn, 0 form)
  scenarios @bpmnkit/engine

✖ orders/order.bpmn  lint 0✖ 2⚠  tests 1/2
    FAIL out of stock
      variables.inStock: expected false, got true
✓ orders/refund.bpmn  lint 0✖ 0⚠
✓ risk-score.dmn
  3 files · 1 failing: orders/order.bpmn
  Watching for changes. Ctrl+C to stop.

What you get

A file list. Every .bpmn, .dmn and .form file under the folder, with a green or red mark for its last check. Hidden directories, node_modules, dist, build, target, coverage and out are skipped.
The editor. BPMN opens in the full diagram editor with in-canvas lint markers; DMN in the decision editor; forms in the form editor.
Simulation. The Play button runs the diagram in the browser on @bpmnkit/engine, with tokens drawn on the elements they sit on. DMN files in the same folder are deployed with it, so business rule tasks evaluate.
Saving back to disk. Edits are written about half a second after you stop, or at once with Ctrl/Cmd+S. Each save is written into the file that is already there, keeping its indentation, attribute order and comments, and is only used if it reads back as the same model — the same writer as the VS Code extension, so moving a box changes the lines for that box, not the whole file.
Live reload. Change a file anywhere else — your text editor, git checkout, a code generator — and the open diagram reloads. If you have unsaved edits in the browser at the same time, nothing is thrown away: you choose between reloading and overwriting.
Checks on every change. Each changed BPMN file is linted exactly as casen lint would lint it (including a project .bpmnlintrc, and connector inputs checked against the element templates from the file’s folder up to the served folder — see workspace templates), and the scenarios in its <file>.bpmn.tests.json sidecar are run as casen test runs them. Changing a .dmn file re-runs the scenarios of the processes beside it. Results appear in the browser’s Checks panel and in the terminal.
Tests you can edit. The Tests tab of Play mode reads and writes the same .bpmn.tests.json sidecar, so scenarios written in the browser are the ones casen test runs in CI.

Flags

Flag	Default	What it does
`--port <n>`	`4747`, or the next free port	Port to listen on. An explicit port that is taken is an error.
`--no-open`	opens the browser	Print the URL without opening a browser.
`--engine ts\|wasm`	`ts`	Engine for the scenario runs after each save. `wasm` runs them on Reebe compiled to WebAssembly, for Zeebe semantics — the engine `casen test` uses. Simulation in the browser always uses `@bpmnkit/engine`.

Deploying and AI

casen dev does not start the AI bridge or connect to a cluster. For those, run the proxy alongside it:

casen proxy start   # port 3033: AI bridge, Camunda API proxy, run history
casen deploy ...    # deploy what you built

Security

The server only listens on 127.0.0.1. It answers only requests addressed to a loopback host name, which stops DNS-rebinding pages, and every API call needs a random token that exists only inside the page it served, so other sites open in the same browser cannot read or write your files. Reads and writes are limited to .bpmn, .dmn, .form and .bpmn.tests.json files inside the project folder: paths that climb out of it, hidden paths and symlinks pointing outside it are refused. Nothing is ever executed on your behalf.