Nicolae Stelian Astefanoaie

Professional Summary

Backend Engineer with 15+ years building and scaling distributed systems, across fintech, media, and telecommunications. Architected a payment platform processing €1.2M+ daily for 7,000+ merchants and led multimedia platform development for Spain's largest media sites (CadenaSER.com, AS.com). Drives technical direction end-to-end — from system design proposals and cross-team coordination to production reliability and engineering process improvements.

Technical Skills

Languages

Java, TypeScript/JavaScript, PHP, SQL

AWS

Lambda, CloudFormation, API Gateway, SQS, S3, MSK/Kafka

DevOps & Observability

Docker, Kubernetes, ArgoCD, Infrastructure as Code, CI/CD, Grafana, Prometheus

Frameworks & Tools

Spring Boot, Node.js, Symfony, React

Databases

PostgreSQL, MySQL, DynamoDB, Elasticsearch

Architecture & Practices

Distributed Systems, Microservices, Event-Driven Architecture, TDD

Professional Experience

Software Engineer

Teya (Fintech), Madrid

Nov 2023 – Present

2 yr 3 mo

Architected the Pay By Link payment platform from scratch — authored design documents, presented technical proposals to a 10-person team, and drove cross-team coordination to unblock dependencies
Grew transaction volume from €0 to €1.2M+ daily, serving 7,000+ merchants; achieved 90K transactions on Black Friday through the WordPress plugin alone, within one month of launch
Defined project milestones, created technical task breakdowns, and designed API specifications for CMS integrations (WordPress, Shopify, Magento, PrestaShop)
Owned PCI-DSS compliance, 3DS authentication integrations, and API key management across all payment flows
Established code review standards and shaped team engineering processes — sprint workflows, on-call rotations, and deployment practices
Stepped in to deliver frontend work (checkout page, merchant onboarding) when team capacity was limited, ensuring feature delivery timelines were met

Software Developer

Aircall (Telecommunications SaaS), Madrid

Jan 2022 – Oct 2023

1 yr 9 mo

Owned call lifecycle subsystem — reception, routing, event processing, and recording — on a platform handling tens of millions of calls monthly
Diagnosed and resolved production incidents across Twilio, Datadog, and AWS as part of on-call rotation
Optimized Lambda execution paths to meet response time SLAs under high-throughput conditions

Senior Software Developer

Novabase (Consultant to Prisa Group), Madrid

Mar 2015 – Jan 2022 (two engagements)

6 yr 2 mo

Built multimedia management systems for Spain's largest media platforms (CadenaSER.com, AS.com, Meristation.com, CanalPlus)
Designed automated audio processing pipeline: ad detection, segment extraction, and concatenation — publishing radio shows to web, Alexa, Google Assistant, and Apple Podcasts within 15 minutes of broadcast
Led CDN migration from Akamai to Fastly/S3, reducing costs by 40%; migrated content systems to ARC XP (Washington Post's platform) using API Gateway, Lambda, SQS, and Step Functions
Delivered CMS for 40 LATAM radio stations with live streaming, content management, and web publishing
Authored system design documents, led architectural proposals across teams, mentored developers, and drove adoption of testing practices

Certifications

AWS Serverless

Amazon (2022)

Certified Symfony Developer

SensioLabs (2018)

Algorithms Specialization

Coursera (2019)

PHP Certified Engineer

Zend Technologies (2010)

Education

BS in Computer Science

Faculty of Computer Science
University A.I. Cuza, Iași, Romania
(1999–2003)

Languages

Romanian

Native

English

Professional

Spanish

Full Professional

Earlier Career

Senior Software Developer — IBM, Madrid (Aug 2017 – Apr 2018 · 8 mo)
Senior Software Developer — PromoTouch Global, Madrid (May 2014 – Mar 2015 · 10 mo)
Software Developer — Pipeline Software, Madrid (Jul 2012 – Mar 2014 · 1 yr 8 mo)
Software Developer — Dejavu Arts, Madrid (Apr 2011 – Apr 2012 · 1 yr)
IT Team Lead — Romanian Border Police, Otopeni Airport (Dec 2005 – Apr 2011 · 5 yr 4 mo)
Junior Software Developer — Petar Computers, Botoșani, Romania (Feb 2005 – Dec 2005 · 10 mo)