Florin Cernat
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Florin Cernat

Available for new contracts

Senior Java Developer · Contractor

Backend systems that hold up in production, built faster with AI.

9+ years designing and shipping Java services for banking, fintech, healthcare and streaming products that cannot afford downtime. I join your team as a contractor, take ownership of hard backend problems and bring AI into both the product and the way it gets built.

Tell me about your project See services
9+
years of professional Java
5
industries: banking, fintech, healthcare, streaming, public sector
B2B
contract, fully remote, EU time zone

Services

What I can take off your plate

Java backend development

Spring Boot services, APIs and integrations: designed for clarity, tested properly and documented so your team can own them after I leave.

AI integration

Add LLM features to existing Java products: document understanding, semantic search (RAG), assistants and agents that call your real APIs safely.

Performance audits & modernization

I find why your system is slow, unstable or expensive to run (queries, memory, architecture) and propose concrete fixes ranked by impact. Then I can implement them, including Java 8 upgrades and breaking up monoliths.

AI-assisted delivery

I use AI coding agents daily, with review discipline. I can help your team adopt the same workflow: faster output without lower quality.

Selected results

Outcomes, not just tickets closed

  • €150k+saved in vendor costs with an in-house Spring Boot adapter for a major European bank’s e-banking system.
  • 50,000+users paying contactless through the Garmin Pay integration I built for a European banking app.
  • +60%performance and reliability on a UAE business-banking app, with 50% fewer customer issues, as tech lead.
  • £5M+VC funding secured by a London payments startup whose backend I led from the architecture phase.
  • 2h → 15mdeploy pipeline time after fixing performance issues in a global healthcare product.
  • 100+Kafka producers and consumers kept consistent while splitting a banking monolith into microservices.

Experience

Where the 9+ years went

Banking, fintech, healthcare and streaming: long-lived backend systems with real users, real money and real consequences when something breaks.

  1. May 2026 – now

    Senior Java Developer (Contractor) · Leading US streaming platform

    Solution and technical designs for new features. Configurable search ranking the business tunes without code changes, a new EXTRA video type across the platform. Java, Spring Boot and Quarkus microservices on AWS.

  2. 2025 – 2026

    Java Automation Developer & Scrum Master · European Commission

    Secure document-exchange platform. Built the REST API test automation framework, Selenium regression suites that saved 3 days of manual testing, and a Java virtual-threads stress tool simulating 50k+ requests.

  3. 2019 – 2025

    Senior Java Developer & Tech Lead · OceanoBe

    Banking cloud migration to microservices with Kafka, Garmin Pay and AliasPay payments, fraud-detection integration. Tech lead for a UAE business-banking app and a London payments startup. Earlier: market-risk platform for a major Italian bank and a global healthcare product.

  4. 2017 – 2019

    Java Developer · UniCredit Bank

    Spring Boot adapter extending the e-banking system that saved €150k+ in vendor costs, customer-data sync over ActiveMQ, the Instant Payments admin panel, and 3 test automation projects.

  5. 2014 – 2017

    BSc Computer Science · Alexandru Ioan Cuza University, Iași

How I work

Simple engagement, no surprises

  1. 01

    Intro call

    30 minutes to understand the problem, the team and the constraints. Free, no obligation.

  2. 02

    Scope & proposal

    A short written plan: what gets built, milestones, and a daily rate or fixed price.

  3. 03

    Delivery

    Weekly demos, code in your repository from day one, clear updates in your channels.

  4. 04

    Handover

    Documentation, tests and a walkthrough so the work stays useful long after the contract ends.

AlsoBusiness process automation with AIFor companies in Romania I also build AI automations: invoices, emails, reports and internal workflows that run on their own.Read more in Romanian

Writing

Notes from the work

All articles

Contact

Have a project in mind?

Tell me what you are building and where you are stuck. I usually reply within one working day.

Prefer email or LinkedIn?

Email me LinkedIn

Tell me about your project

Two minutes of your time. It helps me reply with something concrete instead of a list of questions.