# Runtimes

By default, Pykka builds on top of Python’s regular threading concurrency model, via the standard library modules `threading` and `queue`.

Pykka 2 and earlier shipped with some alternative implementations that ran on top of `gevent` or `eventlet`. These alternative implementations were removed in Pykka 3.

Note that Pykka does no attempt at supporting a mix of concurrency runtimes. Such a future feature has briefly been discussed in issue #11.

- Threading
  - Installation
  - API
    - `ThreadingFuture`
      - `ThreadingFuture.get()`
      - `ThreadingFuture.set()`
      - `ThreadingFuture.set_exception()`
    - `ThreadingActor`
      - `ThreadingActor.use_daemon_thread`