Examples

Six runnable programs under examples/, each a small application built around one machine. Every one runs in CI (test/unit/examples/), so they keep up with the engine. Each page says what the example does, shows its machine, walks through how it is built, and draws its main path as a sequence diagram.

Each also says how it runs, along the two axes of execution models: its semantics — does the caller wait for the result, or hand the event to a worker? — and its execution model — the caller’s own thread, a background event loop, or coroutines on the caller’s loop. Between them the examples cover each combination an application meets:

example	what it is	semantics	execution model	why
minimal	the smallest machine, driven by a script	synchronous — DurableRunner	background (the default)	a script: nothing to choose
place_order	an order lifecycle: retries, a selector, on error	synchronous	background	scenarios replayed one after another
webhook_payment	a payment driven by webhooks, with a durable timeout	asynchronous — DistributedRunner + a worker	background (FastAPI’s def handlers run in a thread pool)	the webhook must answer at once; a worker advances the machine
nicegui_wizard	a multi-step form that survives reloads and restarts	synchronous — AsyncDurableRunner	coroutines	NiceGUI calls its handlers on its event loop
inline_transaction	an order whose state commits with the shop’s own writes	synchronous	inline	one transaction for the shop’s rows and the machine
monitor_demo	seeds a store with executions in every state, for the monitor	synchronous, with the trace on	background	a one-off seeding script

Run any of them from the repository root, for example:

uv run python -m examples.minimal.run

• minimal — the smallest machine
• place_order — an order lifecycle
• webhook_payment — a payment driven by webhooks
• nicegui_wizard — a form that survives reloads and restarts
• inline_transaction — one transaction for the shop and the machine
• monitor_demo — data for the monitor