(Senior) Backend Engineer (m/w/d)

📍 Bielefeld, Deutschland (hybrid) · Vollzeit · Tech & Data

We are building the most modern screwdriver for German SMEs and our backend is at the heart of it. We are expanding our tech team with a (Senior) Backend Engineer, who will bring our APIs, integrations, and AI workflows forward.

You build the backend and integration architecture that runs our AI-native B2B-commerce business. From APIs to event-driven architecture to integrating LLMs and ML models in productive workflows. You think in systems, build pragmatically, and know when MVP is better than perfection.

If you think in architecture, build pragmatically, and have a passion for tech in an AI-native setup, this is your next step.

Aufgaben

Backend & APIs

• REST/GraphQL-APIs develop (Python)
• Cloud Functions build on GCP
• ERP-, CRM- and supplier-APIs integrate
• PostgreSQL / Firestore / BigQuery — data modeling and performance optimization

Event-driven Architecture & Automation

• Event-driven systems build with GCP Pub/Sub
• Workflow orchestration with n8n or Airflow
• Robust error handling, retry logic, and monitoring

AI & LLM Integration

• LLMs (OpenAI, Anthropic, …) integrate for data extraction, routing, and classification
• Ai-agents build for autonomous workflows
• RAG-workflows, Vector DBs, Prompt Engineering
• Guardrails and error handling for non-determinism

AI-assisted Development

• Ai-tools (Cursor, Claude Code) use effectively
• Best practices establish for AI-assisted development in the team
• Code-reviews, testing, CI/CD-pipelines

Infrastructure

• CI/CD with GitHub Actions / Cloud Build
• Infrastructure as Code with Terraform
• Monitoring, logging, alerting

Qualifikation

Muss

• 5+ years backend development
• Very good knowledge of Python
• Experience with serverless architectures (Cloud Functions, AWS Lambda, etc.)
• Solid understanding of event-driven architecture (Pub/Sub, Message Queues, Events)
• Experience with SQL and relational databases (PostgreSQL, etc.)
• Familiarity with REST APIs, Git, and CI/CD-pipelines
• KI/ML as a tool, not buzzword: you use LLMs to make workflows smarter, not more complex
• Pragmatism: MVP over perfection, speed over over-engineering

Nice to have

• LLM-integration for data extraction from emails, PDFs, request documents
• Intelligent routing & decision making with ML models
• Predictive pricing, forecasting or anomaly detection in processes
• Prompt Engineering & optimization of LLM-outputs
• Ai-agents for autonomous workflows
• Handling non-determinism: error handling, guardrails, feedback loops
• Clean data preparation for ML models and RAG-workflows
• GCP-experience (Cloud Functions, Pub/Sub, BigQuery)
• Workflow/orchestration-tools like n8n, Airflow, Zapier or make
• Terraform or other IaC-tools
• Firestore / NoSQL
• Vector DBs, RAG, fine-tuning, CV APIs
• Industry knowledge: connection elements, B2B-commerce

Benefits

• Stack-Ownership: You shape our data and integration architecture actively from API-layer to LLM-workflow.
• AI-native by default: Cursor, Claude Code & Co. are tools at our company, not discussion topics. Who has passion, sets best practices for the whole team.
• Strong environment: You work directly with Technical Lead, Data & Automation Engineers together for short distances, real feedback, fast iteration.
• Influence & Responsibility: You shape our tech platform and build our workflows from scratch with direct impact on architecture and business.
• Focus on talents: Environment for self-motivated top performers with best conditions for growth.
• Transparent compensation – we communicate our compensation model clearly and openly in the first conversation.
• Sense-giving work & tangible product: Your contribution makes industrial procurement more efficient — with direct impact on entire industries.
• Inspiring working environment: modern, high-quality office in Bielefeld with top connectivity
• Near the startup ecosystem in Berlin and OWL

We want to know: Why you? Why now? Why this?

Let's f*ing go!

At getspecialfasteners.com, we value equal opportunities and diversity. We welcome all applications regardless of age, gender, nationality, disability, religion, sexual orientation, ethnic and social background.

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