Ryan Kosai is an award-winning software professional, based in Seattle, WA. Experienced as both an individual contributor and team leader, his specializations include internet telephony, tech startups, and the consumer web.

His interests include data mining, European history, and mechanical watches.

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Algorithm::LinearFit::Random (Perl + C)

Perl module to estimate a multiple linear regression in n-dimensional space. This is typically most useful in inconsistent, overdetermined matrices where the "best fit" line is desired. Runs 100 times faster than the pure Perl equivalent.


sqltidy (Perl)

Useful tool to reformat SQL in an aesthetically pleasing way. Handles complex syntax including deep-nested subqueries and joining to a subselect.


Patch to OpenSIPS (C)

Eliminates memory leaks in "unsafe" module functions. This patch has been used in a production environment routing millions of calls per day.


Horseracing prediction

Currently experimenting with a prediction engine for racetrack betting markets, based on n-dimensional regression, principal component analysis, nearest neighbor clustering, and backprop networks. This work relies heavily on recommender system methodologies from Netflix Prize papers.

Papers: BellKor | BigChaos | PragmaticTheory

Perl Golf Entry

I won a contest at work to print the full lyrics to "99 bottles of beer" with the shortest program. 187 characters of Perl:

$b=" on the wall";sub w{$x=($i||=99)." bottle".'s'x!!--$i.' of beer'}map{print"$x$b, $x.\n",w!=99?"Take one down and pass it around":"Go to the store and buy some more",", $x$b.\n\n"}1..w

Selected Experience

I have been an individual contributor and team leader, working on both remediation and green-fields projects. I write object-oriented Perl, emphasizing readability and conceptual clarity.

Senior Engineer, ExtraHop Networks

Individual contributor on a network-based app monitoring solution. Responsible for data analysis middleware, and front-end data visualization features. Python, Flex, JavaScript.

ExtraHop Networks

Lead Developer - Number Management, Marchex

Team lead and senior engineer, responsible for building and testing Marchex's core VoIP platform. Led a team of five engineers (dev+qa) to sunset and replace several legacy services, coordinating feature development, testing, and the migration of customers to the new system.

I was personally responsible for writing the company's next-gen SIP router, and was a significant contributor to its Asterisk-based call handling platform. Perl, Oracle, Redis.


Lead Developer & Founder, Athleon.com

Raised over half a million in angel and venture financing, then recruited and led a four-developer team to build a product serving hundreds of thousands of coaches and athletes.

Singlehandedly built alpha product in Perl, HTML, CSS, JavaScript, and Flex (LAMP stack). Defined product strategy, road map, and technical vision.




Marchex Venture Award - Team Award, Lead Developer (Q3'11), Marchex Blue Arrow - Individual Award, Engineering (Q2'11), Marchex Blue Arrow - Team Award (Q2'11), Perl "Golf" Tournament - First Place (2010)


UW Business Plan Competition 2008 - Best Consumer Product, UW Business Plan Competition 2008 - Herbert B. Jones 2nd Place Prize, DFJ Venture Challenge 2008 - Finalist, MIT Venture Forum Startup Demo - First Place (Dec 2007)

University of Washington:

Mary Gates Research Scholarship (2006), UW Engineered Biomaterials Research Scholarship (2005), Mary Gates Honors Scholarship (2003, 2004), UW President's Scholar Award (2003, 2004), Robert C. Byrd Honors Scholarship (2003, 2004, 2005, 2006)


B.S. Electrical Engineering, University of Washington (2007). Specialization in analog circuits and biomedical devices.


F. Asphahani, M. Thein, O. Veiseh, D. Edmondson, R. Kosai, M. Veiseh, J. Xu, M. Zhang. Influence of cell adhesion and spreading on impedance characteristics of cell-based biosensors. Biosensors and Bioelectronics. 2007 Dec 8.



Favorite Watches

Jaeger Lecoultre Reverso - Designed in the 1930's, with an Art Deco style, this watch swivels in place, exposing either the front or back of the watch. This mechanism was designed with Polo in mind, and helps protect the watch crystal from impact.


Bell & Ross WW1-97 - Intended to be reminiscent of pilot's watches from the first world war, this model includes a reserve indicator, and a 97-hour power reserve. While some other mechanical watches have longer reserves, 97 hours is quite impressive for an automatic-movement watch.


Jaeger Lecoultre Master Ultrathin - This is an extremely thin watch. 1.85mm thick movement, 4.2mm casing. Plus, it has a transparent sapphire crystal back, so you can see everything.

Master Ultrathin

Rolex Kew A - Probably the most accurate Rolex watches ever released. These watches were certified at the Kew Observatory, which also tested marine chronometers for the Royal Navy. One of the tests involved making sure it continued to keep accurate time while heated in an oven!

Entertaining Reading

The Crack Up (F. Scott Fitzgerald)

Leninigen versus the Ants (Carl Stephenson)

The Last Question (Isaac Asimov)



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