jamesconary

I build the product and lead the team behind it., Product and operations leader who ships the code too., Technical founder. I lead, I build, I ship.

Built the data and AI systems behind a global operation at Duolingo. Two SaaS products, shipped solo.

US Citizen · EU Long-Term Resident (Croatia). Authorized to work in the US and EU, no sponsorship required. Open to relocating to the United States.

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Selected work

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Professional2022 – 2026

Testing Operations Analytics Platform

The data and AI backbone of a global remote testing operation, built solo: ~195 scripts and 87K lines of code powering financial reporting, hours accounting, quality metrics, and automated per-person reporting.

  • Python
  • SQL
  • BigQuery
  • pandas
  • scikit-learn
  • Gemini
  • OpenAI
  • GCP
  • AWS
  • GitHub Actions
  • Docker
Product2026 – Present

Petica.app

A Croatian K-12 education platform, built solo end to end: a Next.js 16 + React 19 + Supabase + Payload CMS app powering AI grade summaries, exam prep, and auto-graded quizzes, built on a resilient authenticated integration client for the national e-Dnevnik gradebook, a provider-agnostic Gemini/Claude/OpenAI layer, AES-256-GCM credential vaulting, and an RLS-first multi-tenant model (170 policies across ~42 tables).

  • Next.js
  • React 19
  • TypeScript
  • Gemini
  • OpenAI
  • Claude
  • Supabase
  • Payload CMS
  • Tailwind CSS v4
  • Stripe
  • Vercel
  • pgvector
Product2025 – Present

Lumina

A voice-first AI language tutor, built solo end to end: a Next.js 16 + React 19 + Payload CMS + Neon Postgres app for Spanish, Portuguese, Croatian, and English, built on real-time spoken conversation over Gemini Live (one native-audio model handling speech-to-text, reasoning, and speech-to-speech over a single bidirectional WebSocket, with ephemeral server-minted tokens so the API key never reaches the browser), AI-generated quizzes with resume-in-progress, Better Auth merged into the CMS user model, and server-locked gamification fields to keep the leaderboard honest

  • Next.js 16
  • React 19
  • Typescript
  • Payload CMS
  • Better Auth
  • Gemini Live API
  • Neon Postgres
  • Tailwind CSS v4
  • Resend
  • Vercel
Product2026 – Present

Sitnice Bitnice

A full-stack bilingual (Croatian / English) recipe and editorial platform, built solo end-to-end: a legacy WordPress site rebuilt on Payload CMS 3 + Next.js 15, with an automated WordPress-to-headless migration pipeline, anonymous IP-hashed ratings, three-tier RBAC, and a multi-layer caching strategy on Vercel and Supabase.

  • Next.js 15
  • React 19
  • Payload CMS 3
  • TypeScript
  • PostgreSQL
  • Supabase
  • Drizzle ORM
  • Tailwind CSS
  • shadcn/ui
  • next-intl
  • Lexical
  • Resend
  • Vercel
  • pnpm