Worked as an SRE on the Infrastructure team. Helped launch Duo's Federal offering.

Worked for two years on Desktop Platform (infrastructure for Dropbox's Windows, Mac, and Linux desktop app), then worked as an SRE on Magic Pocket (Dropbox's exabyte scale block storage system).

Software Engineer

Improved the reliability and functionality of backend systems. Migrated data processing / ETLs from AWS Data Pipeline to a simpler Python + RQ system (reduced complexity, easier maintenance, better monitoring). Replaced email-based alerting system with an error aggregation service. Technologies used: Python, Postgres, redis, RQ, AWS (EC2, Redshift, SQS, S3, CloudWatch, RDS, boto).

Sr. Software Engineer, Backend

Operations for Lumosity.com with over 60 million users. Handled operations at every level of the stack as Lumosity.com grew from 20 million to 60+ million users. Scaling, security, performance & profiling, monitoring, automation, configuration management, being on-call & performing maintenance. Technologies used: sharded MySQL, sharded Redis, HAProxy, Chef, Ruby, Rails, Python, Nginx, memcached, Graphite, Nagios. Hosted on SoftLayer (bare metal) and AWS.

Sr. Software Engineer, Operations

Operations. Maintained and helped build out infrastructure of 200+ dedicated servers. Migrated internal Subversion repos to Git & Github. Set up automated testing & CI (Jenkins) system. Rewrote bash deploy scripts in Python + Fabric.

Built online promotions for top brands (Xbox, Disney, Gap, Condé Nast, Dell, Coca-Cola). Developed Facebook applications; integrated with Twitter search and Facebook Connect for social programs.

Web Developer

Website administration, web development, and software development for the Robofest program at LTU.

Robotics Lab Assistant

I have been using Python for over 10 years, since version 2.2.

I have submitted documentation patches to CPython.

It is my favorite language and I've used it for all kinds of things: web applications, data processing, systems administration / automation, scraping, robotics, monitoring, and much more.

I handled web operations at every level of the stack for Lumosity.com as the site grew from 20 million to 60+ million users: deployment, scaling, security, performance & profiling, monitoring, automation, configuration management, being on-call & performing maintenance.

I have used Chef, Puppet, Ansible, and pure Python (with libraries like Fabric) for automation and configuration management.

I have quite a bit of Linux sysadmin experience (bash scripting, troubleshooting, kernel tuning) for Ubuntu, Debian, RedHat, and CentOS.

Managed a cluster of 200+ bare metal machines at Lumosity, >10k bare metal machines at Dropbox (over three US data centers), and >1k EC2 instances at Duo/Cisco.

I have used EC2, S3, auto-scaling groups, Redshift, RDS, Elasticache Redis, Data Pipeline, ELB, SQS for multiple projects.

I have done quite a bit of automation with Boto2/3, Ansible, s3cmd, and the AWS command line tools.

Experience with building AMIs.

Built and scaled a large Redis cluster for production traffic on lumosity.com. Server migrations, replication, sharding, monitoring, trimming and backing up of data, embedded Lua scripts, etc.

I also wrote a data processing pipeline which used Redis, RQ, and rq-scheduler as part of my work at CommandIQ.

I have done some frontend work with JavaScript, React, and jQuery.

I've also used JavaScript on the backend for an event processing and ETL system.

I have done frontend web development and design.

Pretty comfortable with bootstrap.

Experienced with MySQL, sqlite, Postgres, Redshift, and Percona's tooling for MySQL DBA.

Developed rewards.xbox.com, a large and fairly high traffic Django site, as part of my work at ePrize.

Wrote custom admin functionality for CMS features like content blocks, managing of assets (images, video), translations, and internationalization.

Implemented REST web services using Django and Django REST Framework (DRF).

Experience with MySQL from both the development and operations sides.

Migrations, online schema changes, sharding, replication, tuning, query optimization, monitoring.

Experience with both the official MySQL Server and Percona Server.

Wrote my own multi-threaded traffic replayer that parsed the MySQL protocol from a tcpdump to extract SELECT statements.

Migrated multiple large subversion repositories to git.

Implemented git workflow for a development team of ~50 people (github pull requests + git-flow + the "repo" tool from AOSP).

People come to me when they have git problems :)

Over 10 years experience writing server-side / backend software in Python, perl, Ruby on Rails.

I was active on the Flask mailing list for a few years, answering peoples' questions.

I've written and worked on some fairly large Flask applications.

I taught two online courses here on Codementor for web development with Flask.

I've written custom blueprints, e.g. https://pypi.python.org/pypi/flask-itemshop.

When I'm not using Git for work I tend to use Mercurial.

Senior Software Engineer

Steven Kryskalla

I taught two online classes for Codementor.io. The first class focused on Python for beginners. The second class focused on building web applications using Flask.

Personal details

Steven K.

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