Hi, my name is

Patryk Gniewek.

I build production software, end to end.

I'm a fullstack engineer who ships event-driven systems that move real money — most recently on-chain marketplace infrastructure at Candylabs. On the side I built Marisol, a bilingual AI voice receptionist, solo from scratch.

Get In Touch

About Me

Hi, I'm Patryk. I got into programming for the same reason I got into crypto: neither one ever sits still. There's always a new tool, a harder problem, a shifting landscape to figure out. But the part I enjoy most comes later: when people actually use something I built and tell me how it felt.

Most of my commercial work has been backend for high-stakes web3 systems — real money, external audits, adversarial inputs — including an on-chain presale launchpad at early.cash and an NFT marketplace at Candylabs. These days I work for myself: building products like Marisol and shipping sites for clients, bringing that same web3 rigor to web2.

I own the code I ship — my production debugging record is the proof. Here are a few technologies I've been working with recently:

TypeScript
Node.js
PostgreSQL & Redis
Kafka
React / Next.js
Cloudflare Workers
Docker
Claude Code & MCP agents

Where I’ve Worked

Backend Engineer @ Candylabs

October 2025 - February 2026

Built the marketplace on-chain event indexer and its DB package from scratch: streaming + IDL-driven event decoding, reconciliation loops, Prometheus metrics, structured logging
Built a backfiller service that closes the live indexer's delivery gaps: a periodic sweep of the slot range the WebSocket stream may have missed, with Helius-first RPC and a native fallback, signature-level dedup against the transactions table, and Redis slot checkpoints so a restart never loses progress
Shipped performance infrastructure: a denormalized collection stats table with a precomputation loop (replacing live aggregations), a Bull-backed DB batching queue with serializable retry-safe callbacks, and slot-guard transaction ordering
Extended indexing beyond native marketplace events to track legacy and Core token transfers and cross-list listings from external marketplaces (Magic Eden, Tensor), turning the platform into a multi-marketplace aggregator
Debugged cross-layer production issues: BN serialization corrupting SQL parameters, Uint8Array payloads getting mangled in the queue, and self-CPI events being dropped or duplicated

Some Things I’ve Built

Featured Project
Marisol
Bilingual (EN/ES) AI voice receptionist SaaS, built solo end-to-end. Real-time STT → LLM → TTS pipeline over Twilio telephony, mid-call language switching, a live phone demo line, Google Calendar booking with double-booking prevention, SMS confirmations, and self-serve Stripe billing.
- TypeScript
- Hono
- Cloudflare Workers
- ElevenLabs
- Claude
- Twilio
- Supabase
- Stripe
Featured Project
automation-toolkit
A Claude Code plugin orchestrating 10 specialized agents (orchestrator, workers, quality stewards) through a confidence-scored, quality-gated development lifecycle. 25 reusable skills and 10 MCP integrations (GitHub, Linear, Supabase, Playwright, Sentry, Figma, Stripe...). My daily driver for client delivery.
- TypeScript
- Claude Code
- MCP
- Agent orchestration
Featured Project
TRENUJ — IMC Book Site
Immersive single-page promo site for 'TRENUJ,' a movement-training book — a 3D scroll-driven warehouse walkthrough built around an industrial, hazard-yellow brand identity.
- Next.js
- React Three Fiber
- GSAP
- Tailwind CSS
- Cloudflare Workers