An accredited Internet Astronaut from Finland.

I'm a Ruby developer from Helsinki, Finland. You can find me and my open source projects on GitHub as matiaskorhonen, I occasionally blog about programming and a variety of random things at, and I tweet as @matiaskorhonen.


Ruby like it's 1995

Cast your mind back to the year 1995. Gansta’s Paradise is the top hit of the year. Friends is the hottest show on TV. And just days after I turn nine, Matz releases Ruby publicly for the first time. In this talk I go back to Ruby 0.95 and see what it takes to get it running on modern hardware.

Rails Security: above and beyond the defaults

I originally gave this talk at Rubyfuza 2017 and subsequently repeated it for the Ruby Dev Summit online conference.

The talk is about generic web security with a particular regard towards securing Rails applications.

Things I've made

Piranhas is a book price comparison tool. Search through six Amazon country-specific stores, the Book Depository, and Wordery to find the cheapest source for your books.
Beer Styles
Beer Styles wraps up the 2015 and 2008 BJCP Style Guidelines in a pleasing interface on the iPhone and iPad.
Brewing Utilities
A collection of useful calculators for homebrewing. Refractometer conversion, kettle volume, dilution and boil-off, and priming sugar calculators.

Open source things

Tram Challenge
The goal of the Tram Challenge is to visit all the tram stops on the Helsinki tram system as quickly as possible.
The winner of the 2016 Gopher Gala, Goad does distributed web app load testing via AWS Lambdas
The winner of the 2015 Gopher Gala, Goffee does Global uptime monitoring via Tor.
A Tweetbot custom media endpoint for uploads to S3, written in Go.
Heroku Buildpack: Monit
Run Monit, the open source monitoring utility, on Heroku.
Monit gem
A Ruby interface for Monit


Random Errata is my blog, where I occasionally write about tech stuff, beer making, and other random things.