Freelance full-stack & data developer
products, designed, built and shipped to run in production.
Based in Switzerland · Remote · Reply within 24 h
Co-founder and CTO at Orizn. A CTO’s standards, brought to your projects.
Traffic · 24h
Recent deployments
- main2 min
- feat/apijust now
- fix/cache1 h
- model/v23 h
Regions · p95
- eu-west34ms
- us-east52ms
- ap-south61ms
- edge12ms
Logs
live- 12:04:21OKPOST /api/orders 201 · 42ms
- 12:04:20OKGET /api/feed 200 · 18ms
- 12:04:18WARNcache miss · key=user:912
- 12:04:15OKcron reconcile ✓ · 1.2s
- 12:04:11OKPOST /api/agent 200 · 880ms
- 12:04:08OKGET /api/health 200 · 9ms
Source code
export async function GET() {const data = await db.query()return Response.json(data)}// edge, cache 60s
From the database schema to the pixel, a single point of contact.
Complete web applications: data model, typed API, product UI, shipping to production. Architecture designed to hold up and evolve without a rewrite.
1234567Your data, turned into decisions.
Your messy Excel files, cleaned up and made reliable, then turned into dashboards you can actually use (data here is fictional).
The same file, cleaned and normalized, ready to feed the dashboard below.
Business analytics
30 days analysed
Revenue
€332,812
+12.5%Cost
€196,885
+8.2%Profit
€140,169
+18.3%Orders
2,384
+5.7%Margin
42.1%
+2.1%Websites that convert, from landing page to PWA.
Landing pages, marketing sites, e-commerce and installable web apps (PWA). Fast, polished, built for search and mobile. Designed to turn a visitor into a customer.
A single codebase, on every screen.
iOS and Android apps shipped from the same web core, plus an installable PWA. The same product, everywhere, without tripling maintenance cost.
Mobile
Mobile apps
Hello 👋
Preview
Available balance
2,480.00€
+ 3.2% this weekActivity
See allMock interface, for demonstration only.
AI agents that take action, not just demos.
Assistants and agents wired into your real data and tools. They reason, call functions, and return a verified answer. The kind of AI that saves hours, not the kind that impresses for two minutes.
AIAssistant
Online
Generated replies, sample data
Found on Google and inside AI answers.
Technical search (SEO), answer-engine optimization (AEO) and generative-engine optimization (GEO). Plus content automation: blog articles and social posts generated then published continuously, to grow visibility without spending all day on it.
Visibility score
Cited in
Content queue
- Article: 10 Next.js mistakesPublished
- Carousel: web perfScheduled
- Case study: SEO +40%Draft
One person, from the idea to production.
No subcontracting, no blind spots. A legible process where each step feeds the next, all the way to production.
Get in touch- 01
Scoping
Defining the expected outcome and scope. Sharp priorities, assumptions validated up front.
Scoping workshopScope & prioritiesEstimate - 02
Architecture
Justified technical choices and foundations sized to last and absorb growth.
ArchitectureTech choicesData model - 03
Development
Short iterations, a preview on every branch. The product stays visible and testable throughout.
Short sprintsPer-branch previewsAutomated tests - 04
Production
Automated deploys, performance and compliance. The product truly ships to production.
CI/CDPerformance & SEOGDPR/nLPD compliance - 05
Observability
Logs, metrics and continuous iteration. The product evolves with real-world usage.
Logs & tracesAlertsIterations
Tech stack
A single core wired to an ecosystem of battle-tested technologies: from front-end to data, every brick keeps talking to the others.
And plenty more in the toolbox
The answers, before the first conversation.
Location, scope, stack, budget and timelines. Everything needed to assess a collaboration in a few minutes.
Where are you based, and do you work remotely?
Based in Mies, in the canton of Vaud, between Geneva and Lausanne. Projects are run remotely across French-speaking Switzerland and France, with occasional on-site visits possible in Geneva, Lausanne and the Lake Geneva area.
What services do you offer?
Full-stack web development, website creation, mobile apps, data analysis, artificial intelligence and visibility (SEO, AEO, GEO). From design through to production deployment.
What is your technical stack?
TypeScript, React and Next.js on the web, React Native on mobile, Node.js and Python on the server and data side. Deployed on Vercel and cloud infrastructure, with CI/CD, observability and GDPR/nLPD compliance.
How does billing work for a project?
Fixed-price per project or time-and-materials at a daily rate, depending on scope. Every engagement starts with a scoping workshop that sets the budget and priorities before any commitment.
How long does it take to ship a first product?
A working MVP usually ships within a few weeks, in short sprints with per-branch previews. The exact scope is locked during the initial scoping phase.
Can you take over an existing project or codebase?
Yes. Picking up existing code, technical audits, progressive rewrites and maintenance takeovers are all common engagements.
Let’s work together
An idea, a project, a mission? One message is enough, fast reply.
Guillaume Donni
Freelance full-stack & data developer
Location
Available remote
Mies (VD), Switzerland
Send a message
Reply usually within 24 hours.