Senior Backend Engineer – AWS, PostgreSQL, N8N & API Integrations

TITLE Senior Backend Engineer – AWS, PostgreSQL, n8n & API Integrations DESCRIPTION I am looking for a senior backend systems engineer to implement a proprietary internal operations platform from a completed, professional-grade technical specification. This project has already undergone extensive business analysis and systems design. The business architecture, workflows, and technical requirements have already been documented. This is an implementation project. The objective is to build the system according to the documented specifications. I am not looking for a redesign of the architecture. The architecture has already been approved and documented. Shortlisted candidates will receive a complete implementation package, including: • System Requirements Specification (21 sections) • Architecture Summary • Build Roadmap • Prioritized Backlog • Technical diagrams (ERD and workflow diagrams) Business context and full technical documentation will be shared with shortlisted candidates before work begins. TECHNOLOGY STACK • AWS (RDS, EC2, VPC, Cognito, Secrets Manager, KMS) • PostgreSQL • n8n (self-hosted) • HubSpot API • External REST APIs WHAT I'M LOOKING FOR • Strong AWS backend experience • PostgreSQL schema design, triggers, row-level security, JSONB, and enums • Workflow automation (n8n preferred) • API integration experience • Ability to implement from detailed technical documentation • Strong communication and problem-solving skills Preferred • Experience building secure or compliance-focused systems • Experience with CRM integrations • Experience integrating public APIs Not a Fit If • Your AWS experience is limited to front-end hosting. • You have no experience with PostgreSQL triggers or row-level security. • You prefer redesigning architecture instead of implementing an existing specification. HOW WE WILL WORK This project will be completed through multiple milestones. Each milestone has clearly documented deliverables and acceptance criteria. The first milestone focuses on the platform foundation. Developers who deliver high-quality work and communicate well will be invited to continue building the remaining milestones. Implementation quality is more important than speed. TO APPLY Please answer all five questions. Applications without complete answers will not be reviewed. 1. Describe a project where you joined after the architecture had already been designed. How did you approach understanding it before writing code? 2. Describe your AWS and PostgreSQL experience. 3. Have you worked with n8n or another workflow automation platform? Briefly describe the project. 4. Tell me about an API integration project you've completed. 5. Based only on this job description, what questions would you ask before starting development? Please list your top three. Please begin your proposal with the words "Architecture Reviewed" so I know you have read the entire job posting. Shortlisted candidates will then receive the Architecture Summary and additional documentation for a written technical review before work begins.