Fast to load
Core Web Vitals in the green as the target.
05 / 08 — Services
Web Design & Development
In short
We build web applications, customer portals, dashboards and APIs — with modern front-end frameworks and robust back ends behind them. Performance, security and search visibility are not extras but part of the architecture.
01
How it works.
The typical data flow — from input to result. Every station is replaceable and adapted to your systems.
- 01UX & design
- 02Front end
- 03API & auth
- 04Database
- 05Deployment & CDN
02
What we deliver
Fast, secure web applications and platforms — from front end to API.
- 01Single-page and server-rendered apps with React, Next.js, Vue and Nuxt
- 02Back ends and APIs with Node.js, TypeScript and PHP/Laravel
- 03REST and SOAP web services, JWT authentication
- 04Real-time interfaces with WebSockets
- 05Performance optimisation (Core Web Vitals) and technical SEO
- 06OWASP-based security review and clean deployments
03
A look at the code.
This is what an excerpt from a typical project looks like — readable, commented and without magic. That is exactly how we hand code over to your team.
app.get("/api/rechnungen", auth.jwt({ rolle: "kunde" }), async (req, res) => {
const rechnungen = await db.rechnung.findMany({
where: { mandantId: req.user.mandantId }, // Mandantentrennung serverseitig
orderBy: { datum: "desc" }, take: 50,
});
res.set("Cache-Control", "private, max-age=60").json(rechnungen);
});
// CSP, Rate-Limit und Eingabevalidierung sind Standard — nicht Extra04
What you get out of it.
Built securely
OWASP review, CSP and server-side permissions.
Get found
Technical SEO and structured data included.
Accessible
Keyboard, contrast and screen readers considered.
05
Typical scenarios
05.1
Customer portal
Documents, invoices and status in one place — with roles and secure login.
05.2
Internal tools
Dashboards and admin interfaces that replace spreadsheets.
05.3
SaaS platform
Multi-tenant applications with billing, API and admin area.
05.4
Modernisation
Step-by-step migration of grown jQuery or PHP applications onto a future-proof base.
06
Matching solutions.
S1 
Company knowledge assistant
A chat assistant with RAG over all approved sources, per-document permission checks and answers with citations.
- Answers with evidence
- Permissions preserved
- Runs locally or in the EU
S6 
Private in-house AI platform
A GPU server with local language models, internal chat interface, user management, logging and an API for your own tools.
- Company data stays in-house
- Predictable cost
- One interface for everyone
07
Frequently asked questions
React, Vue or Laravel — which is right?
It depends on team, existing systems and requirements. We work with all of them and recommend whatever is easiest to maintain long term for your project.
Do you care about accessibility?
Yes. Semantic HTML, keyboard operation, contrast and screen reader testing are part of our standard.
How do you secure web applications?
With input validation, secure sessions or JWT, content security policy, server-side authorisation checks and regular dependency updates.
More services
01 / 08
AI Agents & RAG
LLM applications that work with your data and complete tasks on their own.
02 / 08
Local AI Models
Language models on your own hardware — data-sovereign, no cloud dependency.
03 / 08
AI Automation
Business processes that run themselves — with intelligent assistants and integrations.
Ready when you are
Let’s talk.
Describe your project in a few sentences — you’ll get an honest assessment of feasibility, effort and the way forward.
- info@quell-code.com
- Phone
- Call-back on request
- Response time
- usually 2 working days
- Languages
- Deutsch · English · Türkçe