Install

pip install cereyan

Cereyan needs Python 3.11 or newer. The wheel is self-contained: it has no runtime dependencies and includes the Rust core and the web UI. Wheels are published for macOS (Apple silicon and Intel), Linux (x86_64 and aarch64, manylinux 2.28), and Windows (x86_64).

pipuv

pip install cereyan

uv add cereyan

Check the install:

cereyan --help
python -c "import cereyan; print(cereyan.__version__)"

What gets created

The first run creates the runtime home, ~/.cereyan by default, holding the SQLite database and, later, server.json while a server runs, secret.key once a secret variable exists, and storage/ for persisted results. Set CEREYAN_HOME or pass --home to put it elsewhere; see Engines and the home directory.

Windows

The Unix socket listener and engine niceness are Unix-only options, rejected or ignored with a message. Two behaviours are weaker on Windows, both of them signal-based:

Behaviour	On Windows
A flow's timeout_seconds offline (python pipeline.py, cereyan run)	Accepted and ignored; the flow runs unbounded. A served run is timed out by the server.
Cancelling a flow blocked in a sleep or an I/O call	The engine is ended rather than interrupted inside the flow, so on_cancellation hooks do not run.

Everything else — the server, the UI, schedules, engines, rules, artifacts, variables, and the MCP server — works the same.

Next: the Quickstart.