Senior Platform Engineer

Who you are

• Have 8+ years of software engineering experience, including 5+ years in a senior IC role owning developer platform, developer experience, or data platform work
• Have owned developer experience as a first-class product. Build pipelines, test infrastructure, framework upgrades, local dev flow. You have measured DevEx metrics (build time, PR turnaround, flake rate) and moved them
• Have straddled backend and data engineering deliberately. You are fluent in TypeScript / NestJS and comfortable in Python. You have built ETL pipelines, worked with a warehouse (Snowflake, BigQuery, Redshift, or equivalent), and shipped systems where data correctness matters
• Go deep on the warehouse and the operational database rather than treating either as a black box. You can reason about Snowflake or similar structures, dynamic tables, warehouse sizing, and query cost, and you have shipped data quality automation: duplicate detection, outlier flagging, schema drift, lineage, whether with dbt tests, a dedicated validation framework, or your own
• Have shipped data quality automation. Great Expectations, dbt tests, custom frameworks, or your own thing. Duplicate detection, outlier flagging, schema drift, and lineage are all patterns you have implemented
• Have taken over a system from a single point of failure. You know how to do knowledge transfer well: pair sessions, written runbooks, shadowing, gradual ownership handover
• Have opinions about test infrastructure at scale. Unit vs integration vs E2E, contract testing, data test fixtures, test parallelisation. You have made these choices in a real codebase and can defend them
• Are AI-native in your engineering practice. Claude Code, Cursor, or equivalent, integrated into your daily flow. You use AI to move faster on framework work, refactoring, and repetitive automation. You have opinions on where AI helps and where it does not
• Communicate in writing first. RFCs, tech docs, decision records. Async by default, but you’re not afraid to “pick up the phone” to rapidly unblock yourself, instead of waiting for a fixed meeting
• Are comfortable with ambiguity. The Application & DevEx charter is broad. You will shape it as much as inherit it
• Experience in climate tech, carbon accounting, or sustainability platforms
• Experience replacing a legacy analytics layer (CubeJS, Looker, Metabase, or equivalent) with a modern stack
• Experience with Prisma ORM at scale
• Experience automating manual data checks into production systems
• Nx or similar monorepo tooling experience

What the job involves

• We are hiring a Senior Platform Engineer (m/f/d) to become the second senior voice in Platform, alongside our DevOps Lead, and to bridge two worlds he cannot cover alone: application-level developer experience and data engineering
• You will build the automation foundation for the manual data quality checks a single team member has held for years and is now transitioning out of.
• You keep our analytics layer running while planning its successor. You raise developer experience as a measurable discipline. You are hands-on, you write code daily, and you set the standard for how the engineering group builds and ships
• Own Application & DevEx in the Platform group. Developer frameworks, application-level tooling, framework upgrades (NestJS, TypeScript ecosystem), test infrastructure, local dev flow, build pipelines. You define "how we build at Cozero" and reduce friction across the engineering group
• Lead the data platform infrastructure. Warehouse and operational database architecture, cost and performance tuning (Snowflake and Postgres, or similar), orchestration (Dagster, Airflow, or equivalent), ingestion and CDC pipelines, transformation layer, environments and deployment for data workloads, and the infrastructure for AI and ML workloads: serving and inference, LLM application infra, evaluation and versioning, cost control. You work closely with our DevOps lead on the layers underneath. You provide the paved path; Data and Engineering build on top of it
• Make data reliability an engineering discipline. Pipeline observability, lineage, data quality checks, alerting and freshness SLOs, test coverage for transformations. Convert tribal knowledge and manual checks into maintained, observable, test-covered systems
• Raise developer experience as a discipline. Build times, test flakiness, local dev flow, repo hygiene, framework upgrade cadence. You measure these and reduce them. AI-assisted tooling (Claude Code, Cursor) is part of the toolkit, and you push the team's fluency here. Eg building skills, agents or Bots to expedite our delivery speed with solid quality gates
• Participate in the on-call rotation. Every senior engineer, including platform, takes a turn as primary or backup on a 2-week cycle
• Mentor across squads. Your work touches every squad's daily experience. Fast, actionable code and design reviews

Benefits

• VSOP: As a valued team member, you'll have the opportunity to join our VSOP pool, allowing you to share in the company's financial success
• 27 days of vacation: We offer 27 days of paid time off on top of national holidays, no matter where you are based
• Flexible working hours: Trust is the backbone of our culture, so you have the autonomy to set your own work hours. We recognize that work-life balance varies for each individual, so you are encouraged to adjust your schedule to suit your personal needs, whether that's spending time with family or focusing on your health and well-being
• Learning budget: You will have a budget of EUR 500 per year to allocate towards any learning and development activities of your choice. You have the freedom to select whatever you believe is best for your growth
• Work from home budget: You will receive a one-off payment of EUR 500 to purchase any equipment you need for your remote office. We provide you with a Mac
• Work from anywhere: We fully embrace remote work and its flexibility. However, we must adhere to the tax regulations specific to each country
• In-person Gatherings: There's nothing like in-person connections to boost team spirit. That's why we organize two types of gatherings: company-wide events twice a year and team-focused meetups twice a year