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Mantvydas Ciuklys

Senior Full-Stack Engineer | React, .NET, Azure

Kaunas, Lithuania | +370 605 00403

mantvydas.ciuklys@gmail.com | https://ciuklys.com

linkedin.com/in/mantvydas-ciuklys | github.com/mantvydasciuklys

Profile

Senior full-stack engineer with 7+ years building operational SaaS products with React, TypeScript, .NET and Azure. Owns features from requirements through production, including billing, debt collection, contract lifecycles and native identity scanning. Combines frontend architecture leadership with hands-on backend delivery, AI integration and experience building and training an engineering team.

Professional Experience

Amber Force / Hiper Consultancy

Continuous employment through Hiper Consultancy's acquisition by Amber Force.

Senior Software Engineer - StorageLogic

  • Co-built StorageLogic, the ERP supporting AllSafe's self-storage and vehicle-rental operations across 53 business locations in the Netherlands, within a three-developer team.
  • Independently built debt collection and contract lifecycle workflows through move-out; also delivered lead generation, tracking and analytics with real-time dashboards.
  • Lead React and TypeScript frontend architecture and delivery across web, iOS and Android, with code reviews and shared engineering standards.
  • Improved billing and payment reliability through retry-safe processing, automated collections and bank reconciliation on Azure for a platform handling approximately 40,000 invoices monthly.
  • Built Swift and Kotlin identity scanning with NFC chip reads and authenticity checks, replacing manual document handling and reducing onboarding work.
  • Built a .NET AI reporting assistant combining retrieval-augmented generation with read-only business-data tools, source citations and checks on generated figures and record references.
  • Developed an ML-based lead qualifier to prioritise incoming leads for sales; not yet released to production.

Software Engineer - Hiper Consultancy

  • Built and maintained a business platform used by Dutch accountancy firms to manage invoicing, projects and HR.
  • Reduced customer-reported issues by 80% by resolving longstanding defects and modernising fragile areas of the system.

Festo

Software Engineer

Internal applications, Office add-ins and delivery automation

  • Promoted from quality assurance to software engineering within months, then built internal applications and Office add-ins with .NET, React and JavaScript.
  • Automated testing and release workflows and supported the move to SharePoint Online, reducing repetitive work and release risk.
Mantvydas CiuklysResume | 1 of 2
Mantvydas CiuklysSenior Full-Stack Engineer
Consulting, products, skills and education

Consulting Experience

UAB Leksinova

Software Engineer

Concurrent part-time contract

  • Built and led a team of four developers and one QA engineer for a national Lithuanian bank, owning recruitment, onboarding and client communication.
  • Trained three developers transitioning from other technology stacks; delivered SharePoint and Microsoft 365 solutions and ran hands-on engineering workshops.

Selected Products

Fragmentum2026 | Independent creator and full-stack engineer | Early access

  • Building a knowledge workspace for links, notes and files with React, TypeScript, Fastify, Prisma and PostgreSQL.
  • Implemented keyword and semantic search, AI answers with source citations, and queued content ingestion and enrichment.
  • Built a Chrome extension and added Capacitor mobile and Tauri desktop shells around the shared web frontend.

Additional contract work

Colonist.io: UI design and bug fixes for a live multiplayer browser game. Persikas: Full-stack bug fixes and stabilisation of a personalised nutrition product.

Technical Skills

Backend and data
C#, .NET / ASP.NET Core, Node.js, Fastify, REST APIs, SQL Server, PostgreSQL, Prisma, Redis, Background processing
Frontend
React, TypeScript, JavaScript, Mantine, Tailwind CSS, TanStack Query & Router, Vite, Accessible UI
Cloud and testing
Azure, Docker, CI/CD, Azure DevOps, GitHub Actions, Automated testing, Monitoring, Playwright
Mobile and integrations
Capacitor, Swift, Kotlin, Tauri, NFC document scanning, Chrome extensions, Payments, Authentication
AI and engineering
RAG, MCP, Semantic Kernel, Semantic search, System design, Mentoring, Code review, Workflow automation

Education and Languages

Bachelor of Information Systems
Kaunas University of Technology, 2016-2020

Languages
Lithuanian (native) | English (fluent)