Mid-Level Backend Developer

Genki Test; United States; Hybrid; USD 59,479 - 71,245; Full time

Benefits offered by this job

Employee equity participation

Company-issued MacBook

25 days paid annual leave

Flexible working hours

Regular team off-sites

Job summary

Genki Test, a fully remote startup, is seeking a Mid-Level Backend Developer to join their growing team. You will work on building and evolving the backend system that powers health insurance products for digital nomads. Your expertise in Kotlin and understanding of event sourcing will be vital to navigate and enhance this complex system.

The position offers up to 5,000 EUR/month based on experience, with flexible hours and 25 days paid annual leave, among other benefits.

Qualifications

• Experience in working on larger backend systems in production.
• Ability to ramp up quickly on complex business logic.
• Comfortable with event-driven architecture patterns.
• Focus on code quality and clean APIs.
• Hands-on experience with AI-agentic development tools.

Responsibilities

• Build and evolve core backend systems for our product.
• Develop new features and improve existing system reliability.
• Navigate a system under development and evolve the architecture.

Skills

Backend systems production experience

Event sourcing expertise

AI-agentic development tools

Readable code and meaningful tests

Complex product domain understanding

Tools

Kotlin

Stripe

Heroku/Railway

GraphQL

Job description

Genki means "healthy, energetic, and full of spirit". That is our identity.

We are 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 across 200 countries.

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

We are looking for a Mid‑Level Backend Developer to help build and evolve the core system that powers our products and operations. You will join as the second developer on our backend team and report to the Lead Backend Developer.

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

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

We are 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 have. Send a link to your GitHub profile, code samples, prompts, or any other evidence of your experience.

Experience

• You have worked on larger backend systems in production and understand the complexity they bring.
• You have worked in complex product domains and can ramp up quickly on business logic that is not always obvious.
• You are comfortable with event sourcing, event‑driven architecture, or similar patterns.
• Code quality is important to you: 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 detail and take pride in getting it right.
• You are curious and self‑driven, digging into unfamiliar code, asking good questions, and figuring things out.
• You prefer to understand why something works rather than just make it work.
• You are comfortable making decisions when not all information is available.
• You have worked in a startup or scaleup and understand that pace and ambiguity.
• You thrive in a fully remote, async‑first team and know how to communicate clearly without meetings for everything.
• You are open to different ideas, opinions, and people with diverse cultures, backgrounds, and interests.

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.

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.