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Alex Kubica

Senior Software Engineer

Alex Kubica

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About me

Senior software engineer with 11 years of experience building full stack products and backend systems. Recent work spans financial data pipelines, portfolio APIs, authorization, real time updates, and production infrastructure. Experienced in project ownership, code review, and mentoring.

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Experience

  1. Merklebase

    Software Engineer

    to

    Financial systems at scale

    Built and scaled a digital asset portfolio platform across full-stack development, financial data systems, infrastructure, and AI features.

    Large portfolio position loads
    <1s
    Previously 30s+ timeouts
    Transaction rows migrated
    ~7.3M
    Per client database scaling
    tx/sec in load tests
    1,000+
    Across 50 positions
    • Shipped React, Node.js, PostgreSQL, AWS, WebSockets, integrations, and financial data services for a digital asset portfolio platform.
    • Built lending and credit workflows across frontend screens, backend APIs, database changes, and financial data integrations.
    • Optimized position and P&L history systems with rollups, faster transaction ingest, and reconciliation tooling, cutting large portfolio position loads from 30s+ timeouts to sub-second responses and improving processing from ~10 tx/sec per position to 50-100 tx/sec per position in load tests.
    • Migrated ~7.3M transaction rows and moved client workloads from one shared database to per-client databases with PgCat routing, reducing shared-instance load and enabling per-client resource scaling.
    • Led design and delivery of an RBAC-based permissions system, dividing implementation with another engineer across scoped access, endpoint authorization, invitations, and all-portfolio access.
    • Matured platform infrastructure with Prisma migrations, Terraform-managed services, CI/CD gates, health checks, production alerts, and deployment automation.
    • Developed AI portfolio features with chat tools, document retrieval/RAG, tracing, evaluations, and tested worker/API pipelines.
    • React
    • Node.js
    • PostgreSQL
    • AWS
    • AI

  2. monday.com

    Full Stack Developer

    to

    Product growth meets AI

    Worked on a growth team focused on account setup and post-signup team adoption.

    • Built and shipped product experiments across onboarding, account setup, and adoption flows.
    • Executed A/B tests end to end with product and growth stakeholders to validate team hypotheses.
    • Implemented an LLM-powered chat experience that used monday.com's GraphQL API to create boards.
    • Introduced a stronger technical-spec process for new team initiatives.
    • Wrote internal setup and workspace documentation to help engineers work on team-owned features faster.
    • A/B testing
    • LLM
    • GraphQL

  3. ArborKnot

    Full Stack Developer

    to

    From APIs to design systems

    Built product, platform, and communication workflows across frontend, backend APIs, and operational back-office systems.

    • Implemented a design system from scratch and used it to accelerate consistent product delivery.
    • Built consumer-facing REST APIs documented with Swagger/OpenAPI.
    • Developed campaign-management back-office workflows for operational teams.
    • Helped migrate a legacy monolith toward a microservices architecture.
    • Integrated Twilio and SendGrid to automate SMS, WhatsApp, and email communication flows.
    • REST APIs
    • Design systems
    • Twilio
    • SendGrid

  4. Wix

    Frontend Developer

    to

    Making the web multilingual

    Worked on Wix Multilingual, building and maintaining product experiences for site localization.

    • Maintained and delivered new features in the Multilingual back-office application.
    • Implemented the Multilingual core app for EditorX.
    • Built production frontend features with React and Redux.
    • Mentored junior developers and students.
    • React
    • Redux
    • Localization
    • Mentoring

  5. IDF

    C4I and Cyber Security Directorate

    Full Stack Developer

    to

    Building the foundations

    Built internal web, data, and infrastructure systems across several teams and technology stacks.

    • Built and maintained CRUD applications and internal web platforms.
    • Maintained an authentication module used as shared web infrastructure by other teams.
    • Built an OpenID authorization gateway proxy.
    • Designed and built a no-backend GraphQL API using PostGraphile.
    • Added PostgreSQL support to a MongoDB-based project.
    • Refactored a legacy AngularJS users-and-roles management app into React.
    • Built ETL workflows in a data engineering team.
    • Set up CI/CD in a GitLab environment.
    • Mentored new developers.
    • Authentication
    • ETL
    • PostgreSQL
    • React
    • CI/CD

Core skills

  • JavaScript
  • TypeScript
  • React
  • Node.js
  • PostgreSQL
  • SQL
  • AWS
  • CSS
  • REST APIs
  • GraphQL
  • WebSockets
  • system architecture
  • authentication and authorization
  • ETL
  • AI agents
  • Claude Code
  • Codex
  • CI/CD

Education

2016 to 2019

BSc, Computer Science

Netanya Academic College

2015

Programming Bootcamp

IDF Mamram