Decoupling a Live App with Domain Events
Part 2 of the IHA Migration Series: implementing a dual-write strategy and migrating core services to an event-driven architecture.
Robert Goniszewski
Senior Software Engineer & AWS Certified Solutions Architect
Executive Summary
REF: DESC_2026_02Senior Software Engineer and AWS Certified Solutions Architect (Professional) with 6 years of experience in Fintech and Event-Driven architectures. Expert in Node.js, TypeScript, and AWS Serverless technologies. Proven track record designing high-availability systems including credit scoring engines and AI-driven (RAG/LLM) content platforms. Skilled in Infrastructure as Code (Terraform/CDK) and monolith-to-microservices migration. In parallel, I maintain a private closed-source product built as a sole developer in stable support mode as an engineering lab for new ideas.
Methodology focuses on Domain-Driven Design, type-safety, observability, and cost-efficiency. Technical leadership emphasizes mentoring and the long-term ROI of architectural decisions, ensuring systems scale without technical debt accumulation.
Selected Proof
- OPEN SOURCE
Maintainer of Grimoire, a local-first bookmark manager with thousands of GitHub stars and hosted docs.
- SYSTEMS
Shipped production event-driven and serverless backends across fintech, lending compliance, and SaaS.
- WRITING
Publishes architecture migration notes and open-source retrospectives on goniszewski.com/blog.
OPEN SOURCE
CCTraygoniszewski/cctray
A macOS menu bar app for real-time monitoring of Claude API usage, cost, and burn rate.
SELECTED PUBLICATIONS
ALL ARTICLESFrom Next.js Monolith to Event-Driven Architecture: Why We Started and What We Built
Part 1 of the IHA Migration Series — documenting the move from a Next.js monolith to a distributed, event-driven architecture using RabbitMQ, and the three pain points that made it necessary.
It Happened Again - Building a Platform for Tracking Recurring Events
How I designed and built IHA - a platform for tracking recurring events through structured records and source-backed timelines.
CAREER MILESTONES & PERFORMANCE DATA
Mar 2026 — Present
Senior Full-Stack Developer — RBD (Rodzina Bez Długów)
Building and evolving an in-house CRM platform and adjacent internal tooling in the legal-tech domain. Owning architecture decisions across the stack while handling sensitive PII with appropriate data-protection and access controls. Delivery emphasizes AI-assisted development, iteration speed, and maintainable product architecture.
DOMAINLegal tech — in-house CRM solution and supporting internal tooling
RESPONSIBILITYArchitecture decisions and careful handling of PII-sensitive data flows
DELIVERY APPROACHAI-assisted full-stack development for rapid, high-quality iteration
Jun 2025 — Feb 2026
Senior Backend Engineer — Devopsbay
Modernizing existing code and implementing core decisioning logic for a US mortgage platform using TypeScript and Jest. Ensuring deterministic integer-based monetary calculations and compliance with strict lending regulations. Engineered a PoC for an internal AI-driven SEO automation module using LLMs.
DOMAINUS mortgage decisioning and lending-compliance backend modernization
KEY TECHNOLOGIESNode.js, TypeScript, PostgreSQL, Docker, Jest, DDD
Jan 2025 — Present (Part-Time)
Principal Architect & Sole Full Stack Developer — It Happened Again (IHA)
Designed and shipped a closed-source production SaaS end-to-end as sole developer. The platform is now in stable support mode, with focused after-hours iterations used to test modern architecture patterns and delivery approaches.
MODE & SCOPELTS / Stable with low maintenance workload; sole developer across architecture, backend, infra, and delivery
KEY TECHNOLOGIESNext.js 15, React 19, TypeScript 5, Node.js 22, PostgreSQL + Drizzle ORM, Better Auth, Redis + BullMQ, Meilisearch, Docker, Cloudflare
CORE COMPETENCY INVENTORY
•Event-Driven Architecture
•Serverless & AWS Lambda
•Node.js / TypeScript
•Domain-Driven Design
•PostgreSQL & DynamoDB
•Infrastructure as Code
AI TOOLING EFFICIENCY
- Claude Code: Primary copilot for architectural decision-making and LLM-augmented UI/UX design exploration.
- Codex: Primary assistant for backend implementation, system design, debugging, and deep code reviews.
- GitHub Copilot: Multi-modal coding assistant used across day-to-day development tasks and rapid implementation workflows.
- Google Antigravity: Main AI-driven development IDE, powered by Gemini Pro.
TECH STACK & EXPERTISE
TypeScriptExp: 5 y
JavaScriptExp: 6 y
PythonExp: 1 y
Node.jsExp: 6 y
NestJSExp: 2 y
Express.jsExp: 4 y
ReactExp: 4 y
Next.jsExp: 4 y
SvelteExp: 2 y
AWSExp: 4 y
TerraformExp: 2 y
DockerExp: 5 y
PostgreSQLExp: 5 y
MongoDBExp: 3 y
RedisExp: 3 y
GraphQLExp: 3 y
CURRENT FOCUS & SPECIALIZATION
MAIN FOCUS
Fintech Systems & Event-Driven Architecture
ACTIVE LEARNING
AI/RAG/LLM Integration, System Design
STRATEGIC AREAS
- ■Scalability
- ■Security Hardening
- ■AI Infrastructure
- ■DX Optimization
CERTIFICATIONS & EDUCATION
2023
AWS Certified Solutions Architect (Professional)
Amazon Web Services
2022
AWS Certified Developer (Associate)
Amazon Web Services
2023
Graph Developer (Professional)
Apollo
2018 — 2022
Engineer in Software Engineering
WSB University in Gdansk
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