Senior Backend Engineer – Elixir/Phoenix (m/w/d)

In Kürze ...

At Pets Deli, we’re looking for a Senior Backend Engineer who enjoys building reliable systems and taking ownership of their work - from clarifying requirements and making architectural decisions to writing, testing and releasing code.

• Remote within Germany: you can work from anywhere in Germany, though being based in Berlin is ideal. Residence in Germany is required.
• Work permit: a valid work permit for Germany is mandatory for this position.
• Time together: attendance at our headquarters may be required up to four times a year.
• English as our company language.
• Room to grow: our proactive career development programme supports growth in both your role and position.

Deine Aufgaben

The platform you’ll work on

We’ve developed a custom e-commerce platform built with Elixir and Phoenix. It is the system of record for orders, checkout, billing and subscriptions. You’ll help extend its capabilities, maintain it and progressively migrate functionality from our legacy backend into it.

Alongside this platform, we operate a Node.js serverless backend. Moving functionality into our core platform means understanding existing behaviour, managing dependencies and delivering changes in workable increments.

Our technical environment includes:

• Core backend:  Elixir and Phoenix.
• Database and hosting:  PostgreSQL on AWS RDS, with our core platform deployed on ECS Fargate.
• Legacy backend:  Node.js on AWS Lambda, DynamoDB, SQS and EventBridge.
• Frontend:  Next.js, React and TypeScript, with Tailwind CSS, hosted on ECS Fargate.
• Integrations:  Contentful and payment integrations including Mollie, Klarna, PayPal and Apple Pay.
• Monitoring:  New Relic, Sentry and CloudWatch.

What you’ll do

• Build and maintain backend services, APIs and core functionality in Elixir and Phoenix, including migrating business logic from legacy services.
• Shape solutions with stakeholders: clarify requirements, evaluate trade-offs and break complex work into independently deliverable pieces.
• Make and document architectural decisions, improve existing code and resolve performance and reliability problems.
• Own quality from implementation through release: test critical paths, edge cases and interactions between services before handing work to QA, and use monitoring to validate releases.
• Lead code reviews, mentor other developers and help establish coding, testing and documentation standards.
• Improve development tools, CI/CD and engineering practices.
• Keep delivery visible by coordinating dependencies, raising risks early and communicating changes to scope or estimates.

This is a fully hands-on senior engineering role, with responsibility for both the code you deliver and the technical decisions behind it.

Dein Profil

• At least five years of relevant technical experience.
• Strong Elixir/Phoenix experience, or senior-level experience with a language or framework built on similar principles , particularly functional programming, concurrency and message-based systems.
• Experience building reliable systems that handle many concurrent requests.
• Strong debugging and problem-solving skills.
• Experience with REST APIs, automated testing and CI/CD.
• The ability to work independently, explain technical trade-offs and turn incomplete requirements into a clear delivery approach.

For candidates with an Elixir/Phoenix background, we look for good knowledge of OTP, GenServers, Supervisors, LiveView, Ecto and BEAM.

Experience with PostgreSQL, Docker, Kubernetes and monitoring tools is a plus. Full-stack development experience is a plus, particularly with React, Next.js and TypeScript.

How we use AI

We use AI tools and agentic development pipelines as part of engineering. We’re looking for someone who actively develops with AI and takes responsibility for how it is used: defining architecture, coding standards and rules, reviewing the output and validating the result.

Engineering judgment and ownership remain central to the role.

Deine Chancen

• A meaningful product with real impact on the lives of pet lovers
• A supportive, open-minded, and agile team with lots of creative freedom
• Flexible working hours & remote-first culture (within Germany)
• A modern office in Berlin Prenzlauer Berg (snacks, coffee & 10+ friendly office dogs ?)
• Competitive salary & your choice of equipment (Mac/Windows)
• Personal development budget, internal coaching & regular team events

We believe diverse perspectives make better teams. That's why we explicitly welcome applicants of all backgrounds, regardless of ethnicity, gender identity, disability, age, religion or belief, or sexual orientation.
Our hiring process
The process has three stages:

• 2 Remote introduction calls:  a conversation about your experience, the role and your questions. Saturday appointments are possible & a meet the team session
• First coding session in Berlin:  an on-site pair-programming session.
• Second coding session …