Senior Backend & Automation Architect | n8n, Python, APIs, RAG

Senior Backend & Automation Architect – n8n, Python, RAG, API Integrations We are looking for an experienced Senior Backend / Automation Engineer to help us develop a reliable, production-ready automation system for two companies in Germany operating in the windows and doors industry. We are not looking for someone who simply connects a few n8n nodes, builds chatbots or creates basic AI agents. We already have an existing n8n installation, Google Workspace, ClickUp and a documented automation project with defined business processes and technical requirements. We need an experienced engineer who can review our existing work, identify weaknesses and implement a reliable, maintainable system. Project overview Our goal is to automate business administration while maintaining full control over critical operations. The system should support: * Gmail, Google Drive, Google Calendar and ClickUp integration. * Managing customer projects across two separate companies. * Correctly identifying and matching emails, customers, projects and documents. * Tracking business processes, deadlines and follow-ups. * Processing and analyzing business documents using AI and, where appropriate, RAG. * Comparing document versions and identifying inconsistencies. * Detecting technical differences between quotations, measurements and supplier order confirmations. * Verifying information against reliable sources before updating records. * Human approval for critical actions. * Complete activity logs, error handling, monitoring and recovery procedures. Technical expectations We are particularly interested in experience with: * n8n, Python and REST APIs. * PostgreSQL or comparable database systems. * Backend architecture and workflow orchestration. * LLM integration, RAG and document processing. * Data validation, source tracking and version control. * Reliable error handling, retries, monitoring and logging. * Google Workspace and ClickUp APIs. * Security, access management and GDPR requirements. AI should assist with information extraction and analysis. Business processes and critical decisions must be controlled by clearly defined rules. The system must never silently treat AI assumptions as verified facts. How we want to work We already have an approved project plan and existing infrastructure. We do not want to restart the entire project unnecessarily. Phase 1 – Paid technical assessment Review our existing architecture, documentation and implementation in a strictly read-only environment. Identify technical risks, reusable components and implementation requirements. Deliver a written assessment with findings, recommendations and estimated development effort. No production modifications during this phase. Phase 2 – Implementation After approval, develop the system in clearly defined modules with documentation, testing and acceptance criteria. Each module must be tested and verified before moving forward. All source code, workflows, configurations and documentation must remain under our control. Who we are looking for We prefer an experienced individual engineer who has already built and maintained complex automation systems in production. We value engineering quality, reliability, clear communication and long-term maintainability over fast delivery. We are open to a long-term collaboration if the initial assessment is successful. When applying, please answer: 1. Have you built production automation systems involving n8n, APIs, databases and AI/RAG? Please provide examples. 2. How do you prevent incorrect AI-generated information from being written into business systems? 3. How do you handle failed workflows, duplicate events, inconsistent data and system recovery? 4. Have you worked on existing automation projects rather than building everything from scratch? 5. What would you charge for an initial technical assessment, and what deliverables would you provide? We will start with a limited, paid assessment using documentation and test data. Access to real customer information or production systems will not be granted during the initial evaluation. We are looking for someone who can take genuine technical responsibility for a reliable business system, not just deliver a working demonstration.