Pywren lets you run your existing python code at massive scale via AWS Lambda


  def my_function(b):
    x = np.random.normal(0, b, 1024)
    A = np.random.normal(0, b, (1024, 1024))
    return, x)

  pwex = pywren.default_executor()
  res =, np.linspace(0.1, 100, 1000))

Scaling Examples

40 TFLOPS on Lambda [more]
80 GB/sec read and 60 GB/s write to S3 [more]

Getting started

First, make sure you have an account with Amazon Web Services. Then download and install pywren via PIP as outlined in the getting started materials Then enjoy running your code on thousands of cores simultaneously!


Key technologies leveraged include:

The overall goal is to mimic the Python 3.x futures interface as much as make sense.

Key Limitations:

  • low limit of simultaneous workers (maybe 3k if you reserve ahead)
  • finite amount of time per worker (300 seconds), but [see support for stand-alone workers!]
  • non-trivial function invocation overhead, sometimes 15 sec!


"Occupy the Cloud: Distributed computing for the 99%" arXiv 1702.0402 Eric Jonas, Shivaram Venkataraman, Ion Stoica, Benjamin Recht

Recent news

2017-10-11  Investigating alternative cloud backends for PyWren - We try out serverless offerings from other cloud providers to see how they compare with AWS Lambda

2017-10-11  PyWren 0.3 - Annoucing PyWren 0.3, with region-specific runtimes, better error handling, and a storage API

2017-03-27  PyWren 0.2 - Annoucing PyWren 0.2, bugfix release and interactive setup script.

2017-03-06  PyWren 0.1 - Annoucing PyWren 0.1, with Python 3 support, large-scale reducers, better logging, support for running on arbitray instances, and a new website!

2016-10-27  Microservices and Terabits - Using Pywren to benchmark S3, we achieve over 80 GB/sec of read performance and 60 GB/sec of write performance using Amazon S3.

2016-10-25  Microservices and Teraflops - Can AWS Lambda be used for scientific computing ? Here we use a new platform, pywren, to achieve over 25 TFLOPS using pure python across thousands of simultaneous workers.


PyWren is developed and supported by: