Steven Hazel, Developer in San Francisco, CA, United States
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Steven Hazel

Verified Expert  in Engineering

Software Developer

San Francisco, CA, United States
Toptal Member Since
September 27, 2019

Steven began his career as a software developer with a keen interest in startups and new technologies, and a focus on shipping products. After many startup experiences, he decided to co-found his own company and has spent the past decade building Sauce Labs into a successful enterprise software company.



Preferred Environment

Emacs, Kubernetes

The most amazing...

...project I've built was Sauce Labs, a Saas product for automated software testing used by many tech companies and large enterprises.

Work Experience

Co-founder, CTO

2008 - 2019
Sauce Labs
  • Co-founded the company and was the primary engineer building the initial product.
  • Guided architecture throughout.
  • Led the transition to deploy our service with Kubernetes.
  • Hired and ran the engineering and product teams. Scaled the development team.
  • Architected, coded, maintained, and handed off a complex collection of about a dozen back-end microservices in Python.
  • Built a web app in JavaScript and Python.
  • Authored components in a variety of languages, including Go, Scala, Ruby, and JavaScript.
  • Worked with sophisticated tests and tests infrastructure for a large number of significant companies, including Selenium and Appium tests and most unit testing frameworks and CI systems.
Technologies: Selenium, Kubernetes, Python

Director, Engineer

2006 - 2007
  • Managed the development team through the release of an online movie store.
  • Assisted in the development and product management of several versions of the BitTorrent client.
  • Planned and guided the release of the product.
  • Worked with key stakeholders to secure buy-in for the acquisition of µTorrent.
  • Designed and helped to code a complex web app in Python and Javascript, featuring streaming video and credit card transactions.
Technologies: Twisted, Python

Senior Software Developer

2005 - 2006
Grouper (now Sony Crackle)
  • Designed and built a file-sharing system in C# similar in idea to BitTorrent.
Technologies: C#

Software Developer

2002 - 2003
  • Built a file sharing system in C and PHP.
Technologies: PHP, C


An Async/Await system for Python 2 which inspired the version of this feature included in Python 3.

Apple iOS code-signing implementation in cross-platform Python.


An early supervised compiler/interpreter, allowing online compilation and execution of code in a variety of languages, with a secure container-like back end written in Haskell.

Sauce Labs
A popular Cloud service for web and mobile testing. This involves a Cloud of VMs and mobile devices, and a microservice-based architecture for coordinating the Cloud, executing tests, collecting assets, and serving up an API and UI. I was the primary architect and wrote and maintained much of the code over many years.


Selenium WebDriver, Asyncio, React, FFTW




Selenium, Twisted, Django, Ruby on Rails (RoR), Ant Design


Functional Testing, Continuous Delivery (CD), Continuous Integration (CI), Unit Testing, Functional Programming


Python, C, PHP, Ruby, Scala, Go, Reason ML, Rust, JavaScript, Haskell, C#, CSS, HTML


JSON, MySQL, NoSQL, CouchDB, Redis, MongoDB


Kubernetes, Docker


Async/Await, Scalability, VST, Audio, DSP, Digital Audio Workstations (DAW)

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