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Salary
≈ $34k – $91k per year (Estimated)
Location
Remote (Japan)
Employment
Contractor

Confirmed on the employer's own hiring board on Sep 24, 2026. First seen by Alion on Sep 24, 2026.

Overview
Company
Impact
Profile match
Preferred Networks is a Japanese artificial intelligence company founded in Tokyo in 2014 and long regarded as the country's most technically ambitious AI startup. It created Chainer, one of the first define-by-run deep learning frameworks and an influence on the design of modern autograd systems, and has since built a full vertical stack from its own MN-Core accelerator silicon up to foundation models. The company applies that stack to manufacturing, robotics, materials science through the Matlantis simulator and healthcare, working closely with Japanese industrial partners including Toyota, Fanuc and Hitachi.

Job DescriptionJob Description / 職務内容

PFNは、ハイパーパラメータ最適化を始めとしたブラックボックス最適化問題を効率的に解くためのOptunaというソフトウェアの開発を主導しています。Optunaはオープンソースのソフトウェア(OSS)であり、開発コミュニティはPFNに留まらず国内外に大きく広がりつつあります。このポジションでは、Optunaの機能開発・コードレビュー・コミュニティ運営を共に行うパートタイムエンジニアを募集します。

主な業務内容

- Optunaの機能開発・コードレビュー

- Optunaの開発コミュニティ運営

At PFN, we are leading the development of Optuna, a software for efficiently solving black-box optimization problems, such as hyperparameter optimization. Optuna is an open source software (OSS), and while development is driven by PFN, its community is becoming widespread across the entire world. You will be developing Optuna, doing code review, and taking part in community management together with us as a part time engineer.

Job description

- Development and code review of Optuna

- Optuna developer community management

Qualifications / 応募資格(必須)

- ユーザーを持つプロダクションコードやOSSの開発・運用の経験

- バージョン管理やコードレビューを伴う集団開発の経験

- 高い業務遂行能力と優れたコミュニケーション能力

- ビジネスレベルの日本語能力

- Pythonによるソフトウェア開発の経験

- Experience of developing and maintaining production or open source software released for actual users

- Experience of version control and peer review with teams

- High work morale and communication skills

- Business level Japanese language skill

- Experience in software development using Python

Preferred Qualifications / 応募資格(歓迎)

- コンピュータサイエンスに関する技術分野における学士号・修士号・博士号

- Rustによるソフトウェア開発の経験

- 機械学習についての基礎知識

- リレーショナルデータベースに関する知識・経験

- Kaggle等の機械学習コンペティションにおける優秀な成績

- ベイズ最適化・ハイパーパラメータ最適化・ブラックボックス最適化に関する知識・経験

- ビジネスレベルの英語能力

- Bachelor’s degree, master’s degree or PhD in computer science of related field

- Experience in software development using Rust

- Basic understanding of machine learning

- Expertise with relational database

- Significant results in machine learning competitions such as Kaggle

- Expertise with Bayesian optimization, hyperparameter optimization and black-box optimization

- Business level English language skill

Contenits in resume

- レジュメのフォーマットは一般的な履歴書に従う必要はありません。これまで参加したプロジェクト、アルバイト/インターン、執筆した論文、公開している実装等について自由にお書きください。

- 自身の技術ブログ、GitHubリポジトリ、その他の制作物へのリンクなどがあれば記載してください。

- The format of your resume does not need to follow any particular one. To help us understand as much as possible about you, please write about projects you have participated in, part-time jobs/internships, papers you have written, implementations you have published, etc.

- Please include links to your own technical blogs, GitHub repositories, and papers, if any.

Employment Period / 雇用期間

6ヶ月~

6 months~

Location / 勤務地

東京都千代田区大手町1-6-1 大手町ビル / Otemachi Bldg., 1-6-1 Otemachi, Chiyoda-ku, Tokyo, Japan 100-0004

もしくはリモート勤務 (日本国内に限る) / or remote work (limited to work in Japan)

Selection Process/ 選考プロセス

書類選考

コーディングテスト

面接(複数回)

内定

Document Screening

Coding test

Interview (multiple times)

Offer

Employment terms

労働時間: 週10時間以上(ただし、働く日数や時間は本人の都合に合わせて自由に調整していただいて構いません)

時給: 2500円(応相談)

Allowances

通勤手当

Commutation allowance

Holidays

休日:土曜日、日曜日、国民の祝日、国民の休日、年末年始

Holiday: Saturdays and Sundays, public holidays, Year-end and new-year

雇用形態 / Employment Status

有期雇用

業務委託:応相談

Fixed term part-time employment

Outsourcing contract: negotiable

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