Backend Engineer Intern

⚠️ Note: We are not able to sponsor visas for this role. Candidates must already be based in or near Tokyo, or planning to relocate soon.

We're building Mynago, an AI-powered language learning platform rooted in proven polyglot methods. Real dialogues, cultural context, and spaced repetition. AKA, we are committed to creating a product for people who ACTUALLY want to learn.

Our mission is to bring real, learning-first technology to the world. We build every lesson around the learner: their goals, their level, their life. Not generic content served the same way to everyone.

We're looking for a Backend Engineer Intern to help build and ship the services and APIs that power our platform - the infrastructure that makes the AI actually work for real learners.

What You'll Do

• Build and maintain backend services and APIs powering an AI language learning app used by learners worldwide
• Work with Supabase (Postgres), Edge Functions, and third-party integrations (RevenueCat, Stripe, PostHog)
• Debug and optimize AI pipelines: TTS, lesson generation, model routing
• Own monitoring, bug detection, and proactive fixes

What Makes This Role Special

• Learn by Doing: Build production features that go live and matter to real users - from day one
• Real Impact: Your code will be in the critical path for product stability and growth. This isn't a sandbox
• Startup Culture: Fast-moving, internationally minded team in Shibuya, Tokyo's tech heartbeat
• Ownership: End-to-end responsibility for services you can point to in your portfolio, not tickets from a backlog no one cares about
• Meaning: Be part of a team that genuinely cares about building something meaningful in the language learning space

Who We're Looking For

• University student or recent graduate based in Tokyo, Japan
• Native or fluent English speaker (Japanese is a strong plus)
• Strong interest in backend development and applied AI
• Comfortable with Git and basic cloud deployment on platforms like Vercel, Railway, Render, or similar
• Self-starter who doesn't wait for instructions
• You're resourceful - you dig into docs, debug independently, and bring solutions not just questions
• Independent, detail-oriented, and scrappy, you like turning ambiguity into working software
• Can commit a minimum of 15 hours per week

Bonus points if you have a GitHub, side project, or portfolio you can share. We love seeing what people build on their own time.

The Details

• Commitment: 3+ months, flexible scheduling
• Work Style: Hybrid. In-person every working day during the first 2–3 weeks of onboarding, then at least 1 day per week in Shibuya for team sync. Flexible remote the rest of the time
• Compensation: This is an unpaid internship. We're upfront about that. What you get is direct access to the founder with real ownership for projects, hands-on experience building an AI startup in Tokyo, and a clear path to a paid role based on performance. University credits available on request

About Mynago

• Company: Mynago
• Website: mynago.com
• LinkedIn: linkedin.com/company/langaholic
• Location: Shibuya, Tokyo, Japan

How to Apply

Send your resume to hiring@mynago.com with "Backend Engineer Intern" in the subject line.

Even better, include a link to something you've built. A repo, an API, a side project, anything that shows us how you think and what you can ship.