# Kacper

[@kasin\-it](https://hacklab.so/kasin-it)

Kacper is Software Engineer at Blazity. No AI coding activity was synced in the last 30 days.

Software engineer at Blazity building Next\.js products, headless commerce and agentic developer tooling with TypeScript and Claude Code\.

Joined: 2026-09-11

0 followers · 0 following

## Links

- [GitHub](https://github.com/kasin-it)
- [LinkedIn](https://linkedin.com/in/kacper-sini%C5%82o)

## AI usage (All time)

No activity in this period.

## Accomplishments

### [next\-md\-negotiate](https://github.com/kasin-it/next-md-negotiate)

Public GitHub repository that adds content negotiation to Next\.js, serving Markdown to LLMs and HTML to browsers from the same URL\. Repository owner\.

### [cvforge\-app](https://github.com/kasin-it/cvforge-app)

Public GitHub repository for an AI\-powered CV optimizer that tailors a resume to a job posting for ATS compatibility\. Repository owner\.

### [questioneer](https://github.com/kasin-it/questioneer)

Public GitHub repository for an interview\-preparation app aimed at aspiring software developers \(2024\)\. Repository owner\.

### [Claude Certified Architect – Foundations](https://www.linkedin.com/in/kacper-sini%C5%82o/)

Certification listed on the manually exported LinkedIn profile\. No award date is supplied\.

## Experience

### Software Engineer — Blazity

2024\-06 – Present

Warsaw, Poland

Ships client products and internal platforms covering Next\.js/TypeScript marketing sites, headless commerce, performance and agentic tooling\. Delivered a production marketing site solo by its original deadline with reported Good Core Web Vitals \(LCP \<2\.5s, INP \<200ms, CLS \<0\.1\) and Lighthouse scores above 90\. Owned a SvelteKit/NestJS attractions\-commerce product for over 20 months, including stakeholders and production\. On a two\-person recommendation product, reports 30–40% fewer network requests and cache\-hit improvements from about 55% to over 80% using Redis and Vercel\. Designed ai\-workflow from Jira through sandbox to PR with human checkpoints, and co\-architected ClickHouse\-based next\-cwv\-monitor with an SDK below 5 kB\. Also worked on Next\.js/Shopify/Algolia enterprise commerce, internal LLM workflows, technical SEO, performance audits and CI\.