I build fast websites and web apps for businesses.
I'm César Jerez — a full stack developer in San José, Costa Rica, working at the intersection of web development, electronics, and system architecture. From landing pages to custom internal tools, I build things that work.
What I can build for you
Web apps & internal tools
Dashboards, portals, and custom software built around your workflow.
Discovery
Free call — we scope what you actually need.
Proposal
Fixed price for fixed scope, in writing.
Build
Weekly progress, no black-box silence.
Handoff
All code and credentials — it's yours.
Selected work
TrackBit
Problem — Habit trackers either oversimplify (a checkbox) or overwhelm (spreadsheets nobody keeps up with).
What I did — Built a full-stack habit tracker with streak logic, weekly analytics, and a dashboard people actually open twice a day.
INEX — Architecture Studio
Problem — An architecture studio's work is its portfolio, but their old site buried projects behind slow galleries and a template no one on the team could update.
What I did — Designed and built a fast, image-forward marketing site with a CMS the studio manages itself.
SOLEC — MEP Engineering & Maintenance
Problem — A commercial MEP firm wins work on credibility, but their web presence didn't show the depth of what they do or make it easy to start a conversation.
What I did — Built a clear, credibility-first marketing site with a quote-request flow, on the same foundation that powers ServiceGrid.
ServiceGrid
Problem — Service businesses run on scattered WhatsApp threads, spreadsheets, and phone calls between customers, office staff, and field technicians — and nobody shares a single source of truth.
What I did — Built a white-label service-management platform that unifies customer requests, staff dispatch, and field-worker job tracking — first deployed for SOLEC.
Bufete Solano
Problem — Small law firms lose prospective clients in the gap between a first question and a human reply, and once someone becomes a client, matter status lives in the lawyer's head.
What I did — Built the firm's website plus an AI chatbot for first contact and a shared board where clients track their matters and staff manage the caseload.
STRPS — this site
Problem — Freelance portfolios usually look like a resume with a CSS file.
What I did — Built a Next.js + Payload CMS template flexible enough to run a portfolio and a services business from the same codebase — the one you're looking at.
Things I build for fun
Electronics, CNC, generative sketches — the stuff that doesn't fit a client brief.
Parallax Circles
A pointer-following SVG composition. Concentric rings shift on a per-layer parallax factor while each ring slowly counter-rotates on its own clock.
Gray-Scott
A live reaction-diffusion field running on the GPU. Two virtual chemicals feed, react, and diffuse into coral, maze, and mitosis patterns you can paint into.
Reaction Sphere
Gray-Scott reaction-diffusion running across the surface of an icosphere. Each vertex reacts and diffuses with its mesh neighbors on the GPU, in 3D you can spin.
Notes and build logs
How I got here
Before I wrote a line of production code, I was running cable and programming light boards backstage in theater — learning that a live system either works exactly when it needs to, or it doesn't work at all. That mindset followed me into electronics: CNC machining, PCB design, VHDL. There's no partial credit when a circuit is wrong.
Software turned out to be the same discipline with a faster feedback loop. I bring the same instinct for systems — how the parts fit together, what breaks under load, where the real constraint is — to every web app and client project I take on. It's why I default to simple, well-structured solutions over clever ones.
Core stack
- React
- Next.js
- TypeScript
- Tailwind CSS
- Node.js
- Express
- PostgreSQL
- REST / GraphQL
- VHDL
- PCB design
- Embedded C
- CNC / 3D printing
- Git
- Docker
- CI/CD
- Figma
Have a project in mind?
Tell me what you're trying to build — a couple of sentences is enough to get started. I reply within one business day.
I reply within one business day