Błażej Bartoszewski

About Me

Ibuildmodern,intuitivewebapplicationsasaFrontendDeveloperwithBackendelements.IcurrentlyworkasaDeveloperatastartupunderNDA,buildingfull-stackfeaturesandintegrations,whilealsodevelopingtheCodeWorldsplatform.Beforethat,IworkedontheJustfitupapp.Ihaveshapedmytechnicalskillsthroughprogrammingandmanualtestingcourses.Iloveexploringnewtechnologiesandsolvingcomplexproblems.Inmyfreetime,Iampassionateaboutchoppermotorcycles,gravelbiking,volleyball,anddiscoveringworldcuisines.

Experience

1. Developer · Confidential Startup (NDA)

   05/2026 – present
   • Built integrations with Twilio, Notion, Zoom and MS Teams using OAuth 2.0, webhooks, encrypted tokens and PostgreSQL data synchronization.
   • Developed Claude-powered AI agents with tool calling for SMS, notes and meeting access, including per-agent tool permission policies.
   • Built full-stack features in NestJS and React 19, including fuzzy-search notes, SMS conversation views and global search, and automated the local development environment with tunneling and self-healing webhooks.
   • TypeScript
   • NestJS
   • React 19
   • PostgreSQL
   • Drizzle ORM
   • Redis/BullMQ
   • Claude API & Agent SDK
   • Tailwind/shadcn
   • Docker
   • GitHub Actions
   • Vitest
   • Playwright

2. Developer (part-time) · CodeWorlds

   2021 – present

   Gamified platform for learning programming

   • Built the responsive navbar and the About Us section of a live gamified learning platform, and deliver UI/UX improvements, new features and production fixes based on user and team feedback.

3. Developer · Justfitup

   2018 – 2021

   Platform for trainers, nutritionists and their clients

   • Built the navbar, data-driven dashboards and responsive landing pages for a fitness and wellness platform, and delivered ongoing UI improvements across the live application.

Technologies