Fumiaki Kinoshita
Staff Engineer at HERP, Inc.
Tokyo, Japan
Summary
🤩
RockstarFumiaki Kinoshita is a Staff Engineer based in Tokyo with 14 years of experience building reliable back-end systems and developer tools. He has led tech stack standardization and served as technical lead for an AI-driven product at HERP, after seven years developing quantitative trading algorithms, real-time trader UIs, and simulation environments at Tsuru Capital. A dedicated Haskell contributor, he’s made substantive contributions to prominent projects like GHC and bytestring—extending core typeclass instances and hardening low-level byte handling—reflecting deep expertise in functional programming and systems-level correctness. Comfortable bridging research-grade type system work and production engineering, he pairs pragmatic product focus with attention to low-level performance and documentation. Outside work he’s a bird lover, hinting at a patient, observant approach to complex engineering problems.
14 years of coding experience
7 years of employment as a software developer
Github Skills (14)
functional-programming10
monads10
typeclass10
algebraic-data-types10
haskell10
bytestring10
data-structure9
github-repos9
git-repository9
data-structures9
performance-optimization8
api-design7
documentation7
build-automation5
Programming languages (14)
Github contributions (5)
haskell/bytestring
Jun 2020 - Aug 2020
An efficient compact, immutable byte string type (both strict and lazy) suitable for binary or 8-bit character data.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:8 reviews, 5 commits, 8 PRs in 1 month
Contributions summary:Fumiaki primarily contributed to the `bytestring` library by implementing and modifying core functionalities. Their work included addressing architectural issues related to unaligned memory access, adding partition functions to Char8 modules, and deprecating legacy components. They also focused on fixing documentation and enhancing code comments to improve clarity and usability of the library.
byte-string8-bitbytecompactstring
ghc/ghc
Jan 2015 - Jul 2020
Mirror of the Glasgow Haskell Compiler. Please submit issues and patches to GHC's Gitlab instance (https://gitlab.haskell.org/ghc/ghc). First time contributors are encouraged to get started with the newcomers info (https://gitlab.haskell.org/ghc/ghc/wikis/contributing).
Role in this project:Back-end Developer
Back-end DeveloperContributions:10 commits in 5 years 6 months
Contributions summary:Fumiaki primarily contributed to the Glasgow Haskell Compiler (GHC) by implementing and adding instances to Haskell's base library. Their work included adding `Eq`, `Ord`, `Show`, and `Read` instances for `Const` and adding `Monad` instances for `((,) a)`, `(,,) a b`, and `(,,,) a b c`. Furthermore, the user added instances for `Functor`, `Applicative`, and `Monad` to `Kleisli`, reflecting a focus on extending type class implementations within the Haskell ecosystem. These contributions demonstrate a deep understanding of Haskell and its type system.
ghcget-startednewcomershaskellcabal
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.