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Hello, I'm Andrii. Founder of FolioFlux.

10+years shipping products
OSSRuby, Rails & AI contributor

I build and modernize software with Rails and Next.js.

Founder of FolioFlux. I help teams turn complex workflows into dependable web products, from the first product decision to production.

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Direct senior ownership · Remote worldwide

Andrii Furmanets, senior full-stack product engineer
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About

Senior product engineering without the handoffs.

I help product teams turn complex, high-risk work into clear releases. The useful part is not another layer of consulting—it is direct ownership from the interface to production.

How I work

Complex delivery gets easier when product decisions and technical decisions stay in the same conversation. I keep the scope visible, ship in reviewable slices, and close the production details that make software dependable.

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10+

Years building fintech, SaaS, Web3, and developer-facing products.

PublicContributions across Ruby, Rails & AI

Delivery focus

Product decisions stay connected to production details.

  • One owner across product UI, Rails APIs, data, testing, and release.
  • Pragmatic modernization that keeps the roadmap moving.
  • Production AI workflows with approval, evaluation, and observability.

Selected work

Complex products, made usable and shippable.

A live fintech platform and two public products show how decisions move through product UX, application logic, data, testing, and release.

  1. 01

    Personal finance

    FolioFlux

    Live product · 2026

    A clearer picture of your money.

    A finance workspace for freelancers, independent professionals, and their accountants. Import bank and card CSVs, review transactions, and trace totals back to their source rows.

    Product case study: a number you can check

    The problem: a financial total is hard to trust without its source. The workflow starts with a CSV preview, continues through transaction review, and lets you open a dashboard figure to inspect its rows.

    The public walkthrough uses sample data, not customer results. Hosted AI agents and MCP access remain planned. The separate open-source ledger-mcp project demonstrates local, read-only finance tools with synthetic CSV fixtures.

    Inspect the separate local demo
    View FolioFlux sample-data walkthrough
  2. 02

    Local-first finance

    mono-ledger-sync

    Open source · v1.0

    Private financial data, turned into a usable local workspace.

    Monobank sync, review, reports, budgets, backups, and deterministic exports, shipped as a local TypeScript product.

    Sourcenpm package
  3. 03

    AI product workflow

    Draftmora

    Open source · v0.1.2

    An AI task board that keeps approval in the loop.

    Messy notes become structured tasks through agent proposals, explicit human approval, and durable local history.

    Sourcenpm package

Services

Built for the delivery gap between idea and production.

Bring me in where product UX, application logic, integrations, and production risk meet. The engagement stays focused around a concrete outcome.

Discuss the project
01

Full-stack product delivery

A focused workflow carried from product framing and interface design through APIs, data, testing, and release.

  • Product UI
  • Rails + APIs
  • Release ownership
02

Application modernization

Reduce production risk and improve a fragile application in reviewable slices while the team keeps shipping.

  • Architecture
  • Performance
  • Accessibility
03

Production AI workflows

Turn a convincing prototype into a dependable product with tools, approvals, evaluations, fallbacks, and observability.

  • Agent tools
  • Human approval
  • Evals + guardrails
04

Technical delivery support

Join an existing team to unblock a high-risk scope, strengthen the implementation, and leave a maintainable path forward.

  • Technical direction
  • Hands-on delivery
  • Handoff

Process

A clear delivery loop.

Enough structure to keep risk visible, without a heavyweight consulting process.

Clear scope · visible progress · production finish

  1. 01

    Frame the outcome

    Clarify the decision, constraints, and smallest useful release before implementation expands the scope.

  2. 02

    Ship visible slices

    Deliver working increments with direct written updates, tradeoffs, and the next decision clearly stated.

  3. 03

    Harden the edges

    Close gaps in failure states, performance, tests, observability, accessibility, and production behavior.

  4. 04

    Leave clear ownership

    Document what matters, transfer context, and make the next release easier than the first.

Writing

Engineering notes & field observations.

AI systems, Rails, architecture, and product delivery—written from implementation.

18Browse all writing
  1. Ruby

    TypeSafe AI Ruby SDK: Typed AI Answers for Ruby and Rails

    A practical introduction to typesafe-sdk-ruby, an unofficial Ruby SDK for the TypeSafe AI API with typed questions, retries, timeouts, and predictable error handling.

    Read article
  2. GitHub

    Building Your Personal Brand on GitHub: A Practical Guide

    Your GitHub profile is more than a code repository—it's your professional portfolio. Learn how to leverage GitHub's features to build a personal brand that attracts opportunities.

    Read article
  3. AI Development

    What Is OpenClaw? A Practical Guide for Developers

    OpenClaw is an open-source agent runtime that connects LLMs to tools, files, and channels. Here is what it enables and where it fits.

    Read article

Common questions

Before we talk.

The practical details, without another wall of copy.

01What can you own?

A focused product thread from interface and application logic through APIs, integrations, testing, and production release.

02Can you join an existing team?

Yes. I work directly with product, design, and engineering teams, taking responsibility for a clear scope without forcing a rewrite.

03How does a project start?

Share the product, current constraint, and timing. We will identify the smallest useful scope and a clear delivery path.

Have a project in mind?

Let's turn the bottleneck into a useful next step.

Share the product, current constraint, and timing. You'll get a direct answer on fit, risk, and the smallest sensible move.

Book a 30-minute introEmail the brief