Senior Backend Engineer (Sorting)

Location: Hamburg or Berlin, Germany; hybrid workplace

Salary: €70,000–€85,000 per year

Company

hirify.global is a European e-commerce company combining fashion and technology to create personalized online shopping experiences.

What you will do

• Shape product visibility for millions of users by combining ML model outputs with business logic, including campaign boosts and sponsored items.
• Build and own the high-throughput ranking engine “Spotsetter” for fast, deterministic, and fair product sorting.
• Design batch write pipelines that stream data from BigQuery into high-performance Postgres and MySQL stores.
• Develop low-latency serving APIs with Fastify and Node.js/TypeScript.
• Collaborate with data engineers, product managers, and commercial teams on data-driven ranking decisions.
• Work with the Tech Lead on architecture, contribute ideas, and maintain a clean codebase.

Requirements

• 5+ years of experience with backend systems; Node.js/TypeScript is preferred, while experience with Java, Go, or Kotlin is also welcomed.
• Strong hands-on SQL knowledge, including Postgres/MySQL schema design, query optimization, and batch operations beyond basic ORMs.
• Good algorithmic intuition for sorted data, deduplication, latency trade-offs, and constraint logic.
• Interest in bridging backend engineering and ML by serving model scores or ranking data in live systems.
• Clear communication skills in English and a pragmatic, solution-oriented mindset.
• Ownership of ranking problems and backend products, with attention to measurable business impact.

Nice to have

• Experience with job queues such as BullMQ and Redis or with batch-processing pipelines.
• Exposure to AWS Step Functions, CDK, GCP, or BigQuery.
• Background in e-commerce, sponsored products, or ad-tech systems.
• Curiosity about learning-to-rank algorithms.

Culture & Benefits

• Full-time hybrid work in Hamburg or Berlin.
• Flat hierarchies, direct communication, pragmatic decisions, ownership, and trust.
• Inclusive environment focused on acceptance and diverse perspectives.
• Company events, team lunches, afterwork drinks, and other social activities.
• Additional employee perks are available through the company benefits program.

Hiring process

• Apply online through the career page.