Matej
Lietava
Designing and operating production systems across backend services, APIs, cloud infrastructure, and frontend applications — focused on correctness, scalability, and data integrity.
The Index — Experience
003 — 001- Built and operated core RESTful APIs in Node.js behind AWS API Gateway — powering user accounts, crypto transactions, and custody flows.
- Designed and evolved PostgreSQL data models for account, payment, and custody workflows — for integrity, auditability, and query performance.
- Refactored critical transactional workflows to improve throughput, maintainability, and operational confidence across payment and custody processes.
- Delivered third-party integrations for KYC, fiat facilities, and account/payment capabilities — coordinating providers through to production rollout.
- Built services across API Gateway, ECS, RDS, S3, Lambda, and CloudWatch, with infrastructure managed in Terraform.
- Created reusable GitHub Actions and Jest integration tests adopted across repositories; contributed to Zumo's ISO 27001 certification.
- Implemented the OASIS TAXII specification, delivering a STIX/TAXII RESTful API.
- Designed data models and service boundaries for a Java ingestion microservice with AMQP event propagation.
- Acted as Scrum Master across delivery ceremonies.
- Backend (Java) and frontend (JSF/JSP/JavaScript) work modernising a legacy codebase.
- Built BI reports with JasperReports over Oracle SQL.
- Led 3rd-line support.
The Lookbook — Projects
View more on GitHub ↗
A financial-news pipeline that uses an LLM to classify articles into market narratives and map them to companies with sentiment — served through a FastAPI read API and a React dashboard surfacing which narratives are accelerating.
A native iOS app with a searchable Pokémon database and per-entry detail pages showing types, base stats, and abilities — built to explore native iOS development.