Senior Backend Developer

Hub; København; On-site; DKK 900,000 - 1,250,000; Full time

Benefits offered by this job

Pension contributions

Lunch on-site

Team events

Individual development

Job summary

FLEXECHARGE in Copenhagen seeks a Senior Backend Developer to own features end-to-end, primarily in TypeScript/Node.js with AWS serverless tech. You’ll design APIs, integrate with external systems, and occasionally contribute to the React/TypeScript frontend as the platform scales.

The role emphasizes end-to-end ownership, production-readiness, and a focus on the green transition. On-site work in Copenhagen with strong engineering autonomy.

Qualifications

• 3 to 5+ years of professional software development experience.
• Strong hands-on experience with TypeScript/Node.js and AWS serverless architectures.
• Experience with NoSQL data modelling and production data systems.
• Good understanding of authentication, authorization and application security.

Responsibilities

• Taking features from design through implementation and into production.
• Building and operating event-driven, distributed systems with async processing and retries.
• Designing APIs and integrations for enterprise and external systems with stable contracts and versioning.
• Improving existing codebase, refactoring, automated testing and managing technical debt.
• Occasional frontend work in React/TypeScript.

Skills

TypeScript

Node.js

Git CI/CD

Frontend basics (React/TypeScript)

Tools

AWS Lambda

DynamoDB

Event-driven

APIs

Job description

We're looking for an ambitious, self-driven Senior Backend Developer to join our engineering team. You'll work primarily with TypeScript and AWS serverless technologies, with occasional work in our React/Next.js frontend. A growing part of our platform is integrating with enterprise customers and external systems, so you'll design and own APIs and integrations that need to hold up under real-world use.

This is a high-impact role with end-to-end ownership, from requirements to a production-ready solution, and a chance to contribute meaningfully to the green transition.

What You'll Be Doing

• Taking features from design through implementation and into production
• Building and operating event-driven, distributed systems - async processing, retries, failure handling, idempotency
• Designing APIs and integrations for enterprise and external systems - stable contracts, versioning, auth, error handling, backwards compatibility
• Working in and improving our existing codebase - refactoring, automated testing, managing technical debt
• Occasional frontend work in React/TypeScript

Your Experience

• 3 to 5+ years of professional software development, with substantial recent experience in TypeScript/Node.js and AWS serverless or event-driven architectures
• Strong hands-on experience with AWS services - Lambda, DynamoDB, queues, event buses, API services, infrastructure as code
• Experience with NoSQL data modelling and production data systems
• Good understanding of authentication, authorization and application security
• Experience operating production systems - debugging, monitoring, safely deploying changes
• Comfortable with Git-based workflows and CI/CD
• Some React/TypeScript experience, and willingness to make occasional frontend changes

What We Expect at Senior Level

You can independently take a feature or technical problem from requirements to a production-ready solution. You're comfortable navigating unfamiliar code, understanding the blast radius of a change, and making pragmatic calls between delivery speed, reliability and maintainability.

You think carefully about system boundaries and integration contracts, understanding that APIs used by customers and external systems need to evolve safely and behave predictably when either side fails. You understand rollback, backwards compatibility, failure modes and safe deployment for systems handling production data.

You communicate trade-offs clearly and take responsibility for the quality of what you ship.

You're comfortable using AI-assisted development tools as part of your day-to-day work, and curious about how they can improve how software is designed, built, tested and maintained - not just for code generation, but for understanding unfamiliar code, planning changes, testing, reviewing, debugging and documentation. At the same time, you apply strong engineering judgement: you treat AI-generated output as a draft to review and validate, and you remain responsible for the correctness and security of what you ship.

Nice to Have

• Enterprise integrations - SSO/federated identity, webhooks, customer-facing APIs
• AWS CDK or similar IaC tooling
• DynamoDB single-table or composite-key modelling
• IoT, connected devices, telemetry or high-volume event processing
• Multi-tenant SaaS platforms
• Energy tech, EV charging, batteries, solar or energy management
• Data platforms, analytics or data lakes
• ISO 27001 or NIS2 experience
• Next.js

You don't need experience with every technology in our stack. We value strong fundamentals and the ability to learn unfamiliar domains fast.

What Is It Like to Work at FLEXECHARGE?

• Our office sits in Frederiksberg - bright, comfortable, and a genuinely nice place to spend your workday
• You're covered with pension contributions
• Lunch is on-site, delicious, and genuinely healthy and nutritious
• We like each other's company outside of work too, so think Friday bars, plus company team events and team buildings on a team level
• Opportunities for individual development

Our Interview Process

Here's roughly what happens once we've had a look at your application:

• A first conversation, about 30 minutes, you'll talk with our recruiter, get a feel for the role, ask whatever's on your mind, and we'll both get a sense of whether this is worth pursuing further
• Time with the team - a conversation with Artur, our Head of Engineering, and Robert, our CTO
• A technical stage - one or more interviews with the team, which may include a case exercise and follow-up discussions. These can take place remotely or at our office.
• A conversation with Max, our CEO, alongside someone else from the team

Hiring carefully matters to us - we want to get to know you properly, and we want you to get a real feel for us too. If there's anything we can do to make the process work better for you, tell us.

We'd love to hear from you.

Location & Practical Details

This is an on-site role based in Copenhagen.

Only candidates currently located in Copenhagen, or those who clearly state in their application that they plan to relocate, will be considered.

Please note:

• We do not offer visa sponsorship for this role
• We do not offer relocation services

Data Privacy (GDPR)

Applications for this role are processed exclusively through The Hub (thehub.io), our recruitment platform, in accordance with their privacy policy and applicable GDPR requirements. FLEXECHARGE does not process or store candidate data in any of its own internal systems. Your data will be handled confidentially and used only for this recruitment process.