Mid-Level Backend Developer

About Genki

Genki is a Japanese word that means "healthy, energetic, and full of spirit". That's us!

We're a fast-growing, fully remote startup.

We believe in a future where more and more people will be nomads and world residents. Our mission is to help them stay healthy and live well wherever they go. It all starts with great health insurance that works all over the world.

Primary description

Genki · Vietnam (Remote)

Description

Genki means "healthy, energetic, and full of spirit". That's us.

We're a fully remote, profitable startup of about 25 people, five years in and growing steadily.

We build tailored health insurance for long-term travelers like digital nomads, serving over 75,000 people in 200 countries.

Our vision is to help them stay healthy wherever they go, far beyond insurance.

We're looking for a Mid-Level Backend Developer to help build and evolve the core system that powers our products and operations. You'll join as the second developer in our backend team, reporting to our Lead Backend Developer.

Our backend runs on Kotlin with a custom framework built around event sourcing. It's not yet fully documented, so you'll need to be comfortable reading code, asking questions, and finding your way through a system that's still being shaped. You'll build new features, improve testability and reliability, and help evolve the architecture over time.

The product is complex and spans multiple domains. You'll need to build deep understanding quickly and be comfortable making decisions with incomplete information.

We're moving fast, increasingly with AI-agentic development tools. You should have some hands-on experience with these tools and a genuine drive to go deeper.

Show us what you've got. Send us a link to your GitHub profile, code samples, prompts, a vibe-coded job application, or whatever expresses your experience best!

Requirements

Experience

• You've worked on larger backend systems in production and understand the complexity they bring.
• You've worked in complex product domains and can ramp up quickly on business logic that isn't always obvious.
• You're comfortable with event sourcing, event-driven architecture, or similar patterns.
• You care about code quality: readable code, meaningful tests, and clean APIs.
• You have some experience with AI-agentic development tools (Claude Code, Codex, or similar) and want to go deeper.

Our current tech stack

• Language: Kotlin with coroutines
• Framework: Custom, built around event sourcing
• Billing: Stripe
• Infrastructure: Heroku (migrating to Railway)
• AI-agentic development: Claude Code with custom plugin
• APIs: GraphQL

Working style

• You pay close attention to the details and take pride in getting them right
• You're curious and self-driven. You dig into unfamiliar code, ask good questions, and figure things out
• You'd rather understand why something works than just make it work
• You're comfortable making decisions when not all the information is there yet
• You've worked in a startup or scaleup and know what that pace and ambiguity feels like
• You thrive in a fully remote, async-first team and know how to communicate clearly without meetings for everything
• You're as open to different ideas, opinions, and to people with different cultures, backgrounds, and interests as we are

Benefits

• Up to 5,000 EUR/month (depending on experience) with employee equity participation through a vesting program
• Fully remote, from anywhere in the world & live as a digital nomad if you want to (the country list above are just examples)
• Flexible hours, startup atmosphere
• Most of the team is in Europe and Southeast Asia, with a few hours of daily overlap around German business hours
• Company-issued and managed MacBook, plus a desk in your favorite co-working space
• 25 days paid annual leave
• Regular team off-sites to connect in person

Location

Vietnam

Skills