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Alex Kostyniuk, 26
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Stockholm, πŸ‡ΈπŸ‡ͺ
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Team Lead @AMFG
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alexandru.costiniuc00@gmail.com

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Projects

Mellow Lines

Website Source

A code animation studio that turns code snippets into cinematic videos β€” entirely in the browser.

  • Token-level morphing with arc-based animations and three cinematic presets (Precise, Studio, Cinematic)
  • Shiki-powered syntax highlighting with 11 languages, 60 color themes, and 21 background gradients
  • Full video pipeline client-side via FFmpeg WASM β€” exports MP4, WebM, and GIF at up to 60 FPS
  • Deterministic canvas rendering at 1920px+ for sharp, reproducible output
  • Configurable timing controls: transition speed, hold durations, and FPS selection

Mellow fmt

Website Source

An interactive playground for exploring and comparing Prettier and Oxfmt formatting options.

  • Side-by-side comparison of 18 Prettier and 5 Oxfmt-specific options with live code previews
  • Export ready-to-use .prettierrc or .oxfmt.json configs with one click
  • Preset system (Default, Ultracite) for quick opinionated setups
  • Sub-option support for complex settings like experimental import sorting

Alex Posts

Website Source

A technical blog with deep dives into database internals, React mechanics, and JavaScript tooling.

  • 10+ PostgreSQL deep dives β€” MVCC & locking, isolation levels, WAL & shared buffers, B+Tree indexes, window functions, and more
  • React articles β€” From JSX to DOM, mounting vs rendering, Activity component, and Next.js 16 PPR
  • JavaScript & Node.js β€” tree shaking, package lock files, and non-blocking I/O internals

Experience

May 2025 β€” Present
Team Lead

AMFG

Leading architecture and delivery at AMFG across frontend modernization, backend platform work, performance improvements, and team-wide developer experience initiatives while managing a team of 2-3 engineers.

Frontend Architecture & Developer Experience

  • Led migration from Kendo to shadcn/ui and Tailwind CSS, drove investigation, presented ROI analysis, and persuaded stakeholders to invest in a full rewrite that improved iteration speed, developer experience, and UI consistency.
  • Proposed and implemented oxlint and oxfmt, achieving 34x faster pre-commit hooks and significantly reducing CI pipeline times.
  • Proactively migrated the team across major tooling upgrades: npm to pnpm, styled-components to Tailwind, ESLint to oxlint, and Prettier to oxfmt.

Backend Systems & AI

  • Built a 3D model similarity engine using cosine similarity and vector embeddings, leveraging pgvector for vector operations in PostgreSQL - mostly finding top N similar vectors and comparing two vectors.
  • Pioneered the team's first TypeScript backend service, proving developer experience benefits while delivering a low-defect production system.

Performance & Scalability

  • Architected and cut app creation from 10 minutes to 20 second by gutting legacy services and a bloated DB. Replaced 150+ redundant admin configs with 8 fields that actually matter.

Leadership & Collaboration

  • Collaborated closely with the design team to deliver stronger UX outcomes.
  • Achieved 2x personal productivity through AI tooling adoption while maintaining output alongside team leadership and meeting load.
TypeScriptReactNode.jsPostgreSQLTailwind CSSEmbeddings
May 2023 β€” April 2025
Senior Fullstack Software Engineer

AMFG

Led team-wide adoption of AI-assisted engineering workflows, frontend modernization and internal platform initiatives at AMFG, spanning legacy Angular-to-React migration, advanced state management, customer automation tooling

ReactNode.jsNext.jsPostgreSQL
December 2021 β€” May 2023
Middle Fullstack Software Engineer

AMFG

Delivered core platform features across customer onboarding, authentication, planning UX, and workflow automation, with a focus on reducing friction for both customers and internal teams.

ReactNode.jsTypeScriptPostgreSQL
October 2020 β€” November 2021
Junior Fullstack Software Engineer

AMFG

Started my full-time engineering career at AMFG, building foundational fullstack experience while contributing to backend performance improvements and customer-facing admin features.

Node.jsReactPostgres

Contributions

Contribution GraphJanFebMarAprMayJunJulAugSepOctNovDec
591 activities in 2026
Less0 contributions1 contributions2 contributions3 contributions4 contributionsMore

Interests

Preferences

AI Model

AI labs

Components library

UI component system

Frameworks

Web frameworks

Forms

Form libraries

Education

National Technical University of Ukraine 'Igor Sikorsky Kyiv Polytechnic Institute'
National Technical University of Ukraine β€œIgor Sikorsky Kyiv Polytechnic Institute”

Faculty of Informatics and Computer Engineering

Bachelor Degree, Computer Engineering, 2017 - 2021.