Sapiechowski
Full stack developer. JavaScript, TypeScript, NestJS and React, built together with AI.
About
- Based in
- Domaniewice, Poland, CET
- Coding since
- 2008
Over a decade of building web apps and secure APIs. Former head of QA and infrastructure, led ISO 27001 at Sitebox.io. Today AI writes much of the code; I design it, review it and ship it.
Stack
- JavaScript
- TypeScript
- NestJS
- React
- Node.js
- PostgreSQL
- MongoDB
- Docker
- Cloudflare
- ISO 27001
How I work with AI
I decide what we build and how. AI writes, tests and refactors. Nothing ships without my review, tests and CI.
Three tools, one workflow
Pick one to see what I use it for.
Agent in the terminal. Big changes across many files.
> add POST /lessons/:id/feedback with DTO validation and an e2e test
● Reading src/lessons/lessons.module.ts
● Creating src/lessons/dto/create-feedback.dto.ts
● Editing src/lessons/lessons.controller.ts +18
● Editing src/lessons/lessons.service.ts +24
● npm run test:e2e
Tests: 42 passed, 42 total
Editor. Quick, line-by-line fixes.
⌘K replace the manual role check with a @Roles guard
src/lessons/lessons.controller.ts
- if (user.role !== 'teacher') throw new ForbiddenException();
+ @UseGuards(RolesGuard)
+ @Roles('teacher')
@Post(':id/feedback')
Cockpit for coding agents. Parallel tasks, each in its own worktree, ending in a draft PR.
$ npx cezar-run run "add rate limiting to auth endpoints"
● worktree .ai/cezar/worktrees/rate-limit-auth
● implement claude src/modules/auth +86
● verify npm test
Tests: 312 passed
● review codex 2 notes → back to implement
● verify npm test
Tests: 314 passed
● draft PR opened. Nothing merges on its own.
Selected work
-
AI grading for an EdTech platform
Student work graded automatically, cutting grading time by 75%.
NestJS · PostgreSQL · OpenAI · AWS
-
Rate limiting in Open Mercato
Reusable rate limits for login and password reset, in memory or on Redis. Merged into the open-source framework.
TypeScript · Redis · open source
-
ISO 27001 and Cyber Essentials at Sitebox
Led both certifications, from security policies to penetration tests, while building the backend API.
Fastify · MongoDB · security
Experience
- InnovaCrew.ioCo-founder, full stack, AI2024–2026
- Open MercatoOpen-source contributor2026
- Self-employedFull stack developer2014–now
- Sitebox.ioBackend, ISO 270012023–2024
- Gravity GlobalHead of QA & infra2020–2024
- NurtureInfra lead, engineer2017–2020
- MigomediaWeb developer2015–2017
- ProCreative.euFull stack2013–2014
- Happy RebelsWeb developer2009–2013
What I use
- Claude Code
- Cursor
- Cezar
- TypeScript
- NestJS
- React
- JavaScript