Mirakle

Rafal Kleczek

Software Developer · Data-Visualization / Research Engineer · Film Editor & Colorist

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PROFILE

Full-stack software developer with 5+ years of experience building web
applications, APIs, e-commerce solutions, and AI-powered tools — combined with a
parallel practice in data-driven visual storytelling and professional
post-production.

I own products end to end: architecture, backend and frontend, data pipelines,
deployment, and client communication. My core stack is JavaScript/TypeScript
(MERN), Python, and Ruby on Rails, with deep specialization in the Shopify
ecosystem (apps, themes, Admin/Storefront APIs, Liquid) and hands-on integration
of LLM APIs (OpenAI, Anthropic Claude).

Alongside development I run mirakle.dev/research,
where I publish ~30 visually dense, interactive D3.js studies of the Shopify
App Store, built on a Ruby/PostgreSQL scraping platform I designed and
self-host. A separate strand of my work is film editing and color grading in
DaVinci Resolve, where I'm completing a postgraduate diploma.

An academic background in South Asian Studies, Sanskrit, and Anthropology
underpins all of it: editorial rigor, structured research, and a strong instinct
for turning complex material into something clear.

EXPERIENCE

Software Developer / Shopify Developer — Contract & Freelance

Deadwood Digital and independent clients · 2023 – Present · Remote

  • Deliver custom Shopify themes, app integrations, data migrations, and bug fixes for multiple clients
  • Built and published a public Shopify app on the App Store (Gadget.dev platform) — see Deadwood Advanced Filtering under Selected Work
  • Executed a full store migration from Shopify Hydrogen to Shopify Native (see horando.de): complete theme build plus large-scale data migration — thousands of collections and hundreds of blog posts imported into Shopify
  • Built a subscription-based personal-coaching / relationships-advice web platform — a Ruby on Rails application with a PostgreSQL database, self-hosted on Ubuntu (client project; details confidential)
  • Worked across TypeScript, Liquid, Ruby on Rails, CSS, and Shopify APIs
  • Implemented metafields and metaobjects, webhook-based sync systems, and custom storefront logic
  • Managed projects independently from scoping to delivery

Full-Stack Developer (Shopify)

Private Engagement (confidential) · Jul 2025 – Nov 2025 · Remote

  • Developed Shopify apps and themes in a production environment
  • Worked with the MERN stack, TypeScript, Liquid, and Shopify APIs
  • Built API-heavy integrations across the Shopify ecosystem
  • Contributed to both frontend (React / Liquid) and backend services
  • Delivered on real-world, scalable Shopify solutions

Software Developer

Artikuno Commerce · 2021 – Jun 2025 · Remote

  • Built full-stack applications using Node.js, React, MongoDB, and Python
  • Developed 10+ Shopify apps on the MERN stack, published on the Shopify App Store (see Artikuno app portfolio under Selected Work), including 2 LLM-powered commercial apps
  • Designed and implemented REST and GraphQL APIs; integrated SOAP where required
  • Integrated OpenAI and Anthropic Claude APIs for AI-driven features, including chatbot systems and RAG (Retrieval-Augmented Generation) pipelines
  • Built Shopify themes and storefront customizations (metafields, webhook sync, Polaris UI)
  • Used spaCy extensively in production for entity extraction, text classification, and sentiment analysis
  • Built web-scraping pipelines (Scrapy, Puppeteer) for e-commerce competition analysis, Booking.com, Instagram, and the Shopify App Store
  • Designed data models and ETL pipelines (MongoDB, PostgreSQL)
  • Owned all customer-facing technical communication — support, training, onboarding, and documentation

Business Analyst & Developer

Beeanco · 2020 – 2021 (6 months) · Remote

  • Translated business requirements into technical specifications
  • Built lightweight web solutions and integrations for a WordPress marketplace
  • Created documentation for client handoff

University Assistant / Doctoral Researcher

University of Vienna — Institute for South Asian, Tibetan and Buddhist
Studies · 2017 – 2021 · Vienna, Austria

  • Conducted doctoral research, editorial work, and manuscript research
  • Produced structured documentation and rigorous academic writing
  • Assisted in teaching and course preparation

Researcher / Editor

IKSIO, Polish Academy of Sciences — Institute of Mediterranean and Oriental
Cultures · 2017 · Warsaw, Poland

  • Edited the academic journal Acta Asiatica Varsoviensia
  • Organized academic conferences and taught courses
  • Maintained editorial consistency across multiple authors' contributions

SELECTED WORK (SOFTWARE & DATA)

Shopify App Store Dataset & Scraper — Personal Platform

mirakle.dev/research

Role: Architect / Full-Stack Developer

  • Custom-built Ruby scraper that captures the entire Shopify App Store daily — every listing plus the full review history, including developer replies and edits
  • Because it runs daily, the dataset also tracks how listings and reviews change over time; the queue sustains ~100,000 jobs
  • Data lands in a PostgreSQL database, self-hosted on an Ubuntu server and tuned for speed
  • Coverage spans 20,000+ apps and 900,000+ reviews — the complete review history is what makes the dataset genuinely useful
  • Reports are served from curated JSON exports rather than direct DB reads, an optimization that keeps load times fast

mirakle.dev/research — Data-Storytelling Report Series

mirakle.dev/research

Role: Data Analyst / Visual Designer / Developer

  • Author and publish ~30 visually dense, interactive research reports on the state of the Shopify App Store, built in D3.js
  • Angles range across developer behavior, geographic distribution, review mechanics (deletions, edits, reply edits), market concentration, breakout patterns, acquisitions, and conglomerate structures
  • Custom visualization forms — treemaps, slope charts, ridgelines, waffle/ "tone-waffle" charts, bubble charts, and diff-style before/after text views
  • Lean heavily on LLM agents for data extraction, parsing (thousands of reviews at a time), sanitization, and chart design
  • Produce vertical, mobile-first video versions for LinkedIn — simplified visuals, beat-matched slide changes, and AI-generated (uncopyrighted) music

Deadwood Advanced Filtering — Public Shopify App

apps.shopify.com/status-location-filter

Role: Sole Developer · Platform: Gadget.dev · Published May 2026

  • Extends Shopify's native product filtering to stock status (preorder, backorder, in-stock) and warehouse location
  • Automatically assigns product statuses and syncs inventory data as structured JSON to variant metafields for frontend customization
  • Real-time stock synchronization, custom location labels, inventory grouping by warehouse
  • Tiered plans (Free → Plus); built and shipped end to end on Gadget.dev

Artikuno App Portfolio — Shopify App Store (MERN)

apps.shopify.com/partners/ac22

Role: Developer (employer-owned apps, Artikuno Commerce)

  • Contributed to a portfolio of MERN-stack Shopify apps, including:
    • Trackidex — order & fulfillment tracking and analytics dashboard
    • IPDex — custom shipment-time indicator by region/country
    • Warehouse Wizard — interactive 3PL finder and planning tool
    • Artikuno Commerce Capital — customer-funded fundraising
    • CRMammoth — CRM tooling
  • React, Node.js, Express, MongoDB, Shopify Admin/Storefront APIs, Polaris

horando.de — Hydrogen → Shopify Native Migration

horando.de (German luxury-watch retailer)

Role: Shopify Developer

  • Migrated an extensive storefront from Shopify Hydrogen to Shopify Native
  • Full theme build on Shopify Native
  • Large-scale data migration — thousands of collections and hundreds of blog posts imported into Shopify

Personal-Coaching / Relationships Platform (confidential)

Role: Full-Stack Developer

  • Built a subscription-based personal-coaching and relationships-advice web platform, including a public FAQ/knowledge base
  • Ruby on Rails application, PostgreSQL database, self-hosted on Ubuntu
  • Details withheld for privacy.

Earlier & Independent Projects

  • 2 commercial LLM-powered Shopify apps with RAG pipelines (Artikuno)
  • readingbuddy.deite.org — independent LLM chat / translation assistant
  • Exchange Marketplace visualizations (2021) — interactive D3.js scatterplot (price vs. revenue, log toggle, zoom, revenue-history tooltips) and slope chart (week-over-week price change) on scraped marketplace data
  • Brief maintenance contributions to the open-source visualization library DC.js

SELECTED WORK (FILM EDITING & COLOR)

Documentary Film — Meenamma

https://vimeo.com/1137355159/22552262ee?fl=tl&fe=ec

Role: Editor / Colorist

  • Edited long-form documentary material, shaping narrative structure and pacing
  • Performed a full color grade in DaVinci Resolve, balancing mixed lighting and varied source footage
  • Maintained shot-level grading consistency across environments
  • Managed the edit-to-grade workflow and final delivery

Short Film (Singapore)

https://vimeo.com/1199666937/59cbb49fc2?fl=ip&fe=ec

Role: Editor / Colorist

  • Edited and graded a short film shot in Singapore
  • Full offline-to-finish in DaVinci Resolve Studio

Music Video

https://vimeo.com/1169433120/208f612a32?fl=tl&fe=ec

Role: Editor (primary) / Color (initial pass)

  • Edited with emphasis on rhythm, pacing, and visual continuity
  • Developed an initial color grading pass and visual direction in Resolve
  • Collaborated within a multi-person post pipeline where final DI was external

TECHNICAL SKILLS

Languages

  • JavaScript, TypeScript, Python, Ruby

Frontend

  • React, HTML, CSS, Liquid
  • Responsive / mobile-first UI

Backend

  • Node.js, Express
  • Ruby on Rails
  • REST APIs, GraphQL, SOAP
  • Authentication (OAuth, JWT, API keys), webhooks, event-driven architecture

Shopify

  • App development (MERN stack) and Gadget.dev apps
  • Admin API, Storefront API, Liquid theme development
  • Webhooks, metafields, metaobjects, Polaris UI
  • Store migrations (incl. Hydrogen → Native) and large-scale data migration

AI / NLP

  • OpenAI API, Anthropic Claude API
  • Prompt engineering, RAG systems, LLM agents for data pipelines
  • spaCy — entity extraction, classification, sentiment analysis

Data & Visualization

  • D3.js, DC.js — interactive data visualization for the web
  • Data-visualization and UI/UX design, wireframing
  • Web scraping (Ruby, Scrapy, Puppeteer), large-scale daily crawling & change tracking
  • ETL pipelines, data modeling, schema design

Databases

  • PostgreSQL, MongoDB

Infrastructure & Tools

  • Ubuntu server (self-hosting), Git
  • Docker (basic), CI/CD (basic)
  • Basic Azure (image recognition, blob storage)

POST-PRODUCTION SKILLS

Editing

  • Avid Media Composer, DaVinci Resolve (Edit page), Final Cut Pro

Color / DI

  • DaVinci Resolve Studio (primary), node-based grading
  • Shot matching and balancing, look development
  • Scopes: waveform, vectorscope

VFX (basic)

  • After Effects, Fusion

Technical Edge

  • Software-development background applied to post workflows
  • DaVinci Resolve scripting/API experimentation for automation
  • Blackmagic RAW SDK exploration — metadata extraction, RAW pipelines
  • Understanding of structured pipelines and failure points in post-production

Post Tools

  • DaVinci Resolve Studio, DaVinci Resolve Micro Color Panel
  • Linux-based workflow

EDUCATION

Postgraduate Diploma in Film Editing & Digital Intermediate (DI) — L.V.
Prasad College of Media Studies, Chennai · 2025 – 2026 (expected)

  • Editing in Avid Media Composer, Final Cut Pro, DaVinci Resolve
  • Conform and grading in DaVinci Resolve Studio
  • Color science and DI workflows; basic VFX in After Effects and Fusion

Ph.D. South Asian Studies (in progress) — University of Vienna · 2017 –

  • Focus: philology, sociolinguistics

Ph.D. Sanskrit Studies — University of Hyderabad · 2014 – 2017

  • Focus: philology, linguistics

M.A. Sanskrit Studies — University of Madras · 2012 – 2014

M.A. South Asian Studies — University of Warsaw · 2007 – 2012

B.A. Anthropology — University of Warsaw · 2010 – 2012

LANGUAGES

  • Polish — Native
  • English — C2 (Proficient)
  • German — C1 (Advanced)
  • Russian — B1 (Intermediate)
  • Sanskrit — Research level
  • Tamil — Basic

ADDITIONAL

  • 5+ years remote work across time zones; strong async and client communication
  • Full product ownership — from architecture and data infrastructure to UI, deployment, documentation, and support
  • Editorial rigor and cultural / contextual sensitivity from an academic background in South Asian Studies and Anthropology
  • Company registered in Poland; based in Chennai, India; open to relocation