Senior Software Engineer

Whatnot

. Design, build, and ship features critical to growing the Japan market, including payment and payout methods, logistics integrations, seller onboarding and compliance, and locally tailored buyer and seller experiences .

Posted 10/16/2026full-timeTokyo • JapanSenior💰 ¥19,000,000 - ¥26,000,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates extensive full-stack software engineering expertise with a focus on building and integrating systems for the Japan market. Proficient in leading technical strategy and execution while collaborating with cross-functional teams in a high-growth environment.

Highest-signal resume keywords

Full-Stack ExperiencePython ProgrammingElixir ProgrammingJavaScript ProgrammingNear-Fluent Japanese

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

Software EngineeringSystem IntegrationTechnical LeadershipEnd-to-End Development0→1 Work

Industry Keywords

E-CommerceMarketplaceLivestream ProductJapan-Specific LogisticsPayments Integration

Tech Stack

Tools & technologies

ElixirJavaScriptPython

About the role

Key responsibilities & impact

Design, build, and ship features critical to growing the Japan market, including payment and payout methods, logistics integrations, seller onboarding and compliance, and locally tailored buyer and seller experiences
Own technical strategy for Japan in partnership with the Japan GM
Translate market needs into a roadmap and decide what to build and how
Own technical trade-offs, including how Japan-market work fits into Whatnot's global architecture
Lead execution across multiple workstreams
Coordinate with engineers and cross-functional partners in Japan and globally
Establish the technical foundation for Whatnot's engineering presence in Japan, including architecture, patterns, quality bar, and culture
Work across the full stack to build features for Japan and other global markets
Use Whatnot as both a buyer and seller as part of the job

Requirements

What you’ll need

8+ years of software engineering experience, including at high-growth technology companies
Experience operating as the technical lead of a team or initiative without direct reports
Full-stack experience across backend and frontend
Experience integrating systems end-to-end
Experience with Python, Elixir, and JavaScript
Comfort with 0→1 work in a small team without an established playbook
Near-fluent Japanese and English, written and verbal
Must live in or relocate to the Tokyo area
Must be able to regularly work from the Tokyo office
Must be legally authorised to work in Japan
Bonus: e-commerce, marketplace, or livestream product experience
Bonus: Japan-specific logistics, payments, or identity integrations
Bonus: localizing a global product for Japan

Benefits

Comp & perks

Generous Holiday and Time off Policy
Health Insurance options including Medical, Dental, Vision
Work From Home Support
Home office setup allowance
Monthly allowance for cell phone and internet
Care benefits
Monthly allowance for wellness
Annual allowance towards Childcare
Lifetime benefit for family planning, such as adoption or fertility expenses
Retirement; 401k offering for Traditional and Roth accounts in the US (employer match up to 4% of base salary) and Pension plans internationally
Monthly allowance to dogfood the app
Parental Leave
16 weeks of paid parental leave + one month gradual return to work
In-person onboarding experience at one of our offices