Sami Koskimäki
Principal Software Engineer at Quanscient
Helsinki, Finland
Summary
🤩
Rockstar🎓
Top SchoolSami Koskimäki is a Principal Software Engineer based in Helsinki with 11 years of hands-on experience building everything from machine learning and computer vision to mobile apps and full‑stack web systems. He co-founded multiple ventures and consultancies where he pairs pragmatic product thinking with engineering discipline to maximize customer value and minimize wasted effort. Sami is an active open-source author and contributor—best known for objection.js and notable contributions to the type-safe SQL builder Kysely, including MySQL support and nuanced SQL behaviors like duplicate-key updates. At Quanscient and prior firms he has driven architecture and delivery while remaining deeply technical, often focusing on backend and database query implementation. He holds a Master’s with distinction in Signal Processing and brings a research-informed mindset to practical software problems. A useful but less obvious detail: his work frequently blends rigorous testing and refactoring with subtle bug fixes around SQL schemas and joins, improving reliability in real-world deployments.
11 years of coding experience
13 years of employment as a software developer
Master’s Degree with distinction, Signal Processing, Master’s Degree with distinction, Signal Processing at Tampere University of Technology 1965-2018
English, Finnish
Stackoverflow
250reputation
17kreached
6answers
0questions
Github Skills (16)
typescript10
javascript10
typescripts10
sql10
database-design10
mysql10
typescript-types10
query-building10
testing9
nodejs9
postgresql7
async-await6
heroku-postgres6
orm6
objectionjs6
Programming languages (9)
Github contributions (5)
kysely-org/kysely
Feb 2021 - Jan 2023
A type-safe typescript SQL query builder
Role in this project:
Back-end Developer
Back-end DeveloperContributions:83 releases, 312 reviews, 514 commits in 1 year 11 months
Contributions summary:Sami made several contributions related to enhancing the query builder functionality, specifically for MySQL database support. They implemented features for duplicate key updates and insert ignore statements. They also made documentation updates and refactored a section of the code for improved maintainability. The user focused on the implementation of SQL queries.
browsertype-safesqlitenodejsdatabase
Vincit/objection.js
Apr 2015 - Apr 2022
An SQL-friendly ORM for Node.js
Role in this project:Back-end Developer
Back-end DeveloperContributions:2 reviews, 1775 commits, 364 PRs in 7 years 1 month
Contributions summary:Sami primarily focused on code cleanup and adding tests to the vincit/objection.js repository. Their contributions involved refactoring existing code, as well as adding more comprehensive tests that were related to issue #437, and #443. Furthermore, the user fixed a bug related to joinEager and table names with postgres schema, adding tests for this case.
mysqlnode-jssqlsqlitenodejs
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