REACT AGENCY FOR INTERACTIVE INTERFACES
As a React agency we build component-based interfaces that scale without becoming unmanageable – from a single component to a complete single-page app. We are based in Mönchengladbach and support projects on site in North Rhine-Westphalia and remotely across Germany.
What does a React agency do?
A React agency plans, builds and maintains web frontends based on the UI library React: component libraries, state management, connections to REST and GraphQL APIs, and performance tuning. nextlevels does this for dashboards, shop frontends and customer portals, migrates legacy frontends to React step by step and uses Next.js when server rendering and SEO are required.
What React is – in short
React is an open-source library for user interfaces. Meta released it in 2013; today it is carried by developers from many companies. Interfaces are built from components: small, reusable building blocks with their own state. React is MIT-licensed and has no licence fees.
The current version is React 19. Server Components are stable there: parts of the interface render on the server and reach the browser as finished HTML. The React Compiler has been available as version 1.0 since October 2025 and takes over much of the manual performance tuning. We use both where they help measurably.
React on its own is not a full framework. Routing, data loading and server rendering come from Next.js or TanStack, apps for iOS and Android from React Native. We work out which combination fits your project in the first call.
We areReactdevelopers
We think in reusable components, clean state management and clear data flows so your frontend stays maintainable for the long term.
- Component libraries and design systems
- State management with hooks, context and TanStack Query
- Integration of REST and GraphQL APIs
- Tests, code splitting and performance tuning
Components & reusable UI
We encapsulate UI in clearly scoped components with defined props – so the interface grows without complexity piling up in single files.
Hooks & state management
With hooks, context and libraries like TanStack Query we keep state predictable and server data in sync – without boilerplate sprawl.
Integration into existing systems
React can be adopted incrementally – as an island in a legacy page or as a full app. We migrate without big-bang risk.
Performance & bundle size
Code splitting, memoization and lazy loading: we ship only the code that's needed and keep interactions smooth.
React in our own projects
next-cms and NEXT Orbit
The admin interface of our CMS framework next-cms is built in React, with TanStack Router, Query and Table. NEXT Orbit, our CRM, runs on next-cms as well.
This website
next-levels.de runs on Next.js and React, written in TypeScript throughout.
Kumho Tire Europe app
The Kumho Tire Europe app is built with Expo and React Native – the same component model as on the web.
Services &solutions
From a single component to a complex application – including design system, tests and maintenance.
- UI architecture and component libraries
- Integration with headless CMS and commerce backends
- Migration of legacy frontends to React
- Code reviews, tests and performance audits
Dashboards & data-driven tools
Tables, filters and real-time updates: React combines reactive interfaces with a clear component structure for complex internal tools.
Interactive product configurators
Multi-step inputs, live preview and validation: we build interactive flows that stay maintainable even with many states.
How a React project runs
Cost and duration depend on scope. Our project calculator gives you a first range; the binding figure comes with the offer after the workshop.
First call
You describe the goal, the users and the systems you already have. We tell you straight away whether React fits or whether another route is better.
Architecture workshop
We define the data model, interfaces and hosting and cut the scope into packages. The offer is based on that.
Delivery in iterations
We ship in short steps to a test environment, so you see every stage. Tests and code review are part of each step.
Go-live and operations
We deploy to your infrastructure or run the application for you. After that we handle updates and monitoring if you want.
Not React, but something else?
Looking for an agency for a different frontend or app framework? We build with these too:
Frequently asked questions about React
Your question isn't here? Ask us directly
What is React?
React is an open-source library for user interfaces, released by Meta in 2013 and free to use under the MIT licence. Interfaces are composed of components that manage their own state. A framework such as Next.js or TanStack Start adds routing, data loading and server rendering.
When is React the right choice for our project?
As soon as your interface has a lot of interaction, changing state or recurring building blocks: dashboards, configurators, portals, shop frontends. For a simple content page without interaction, React alone is too much. A CMS or a statically generated site is enough then.
React or Next.js – what do you recommend?
Next.js does not replace React; it is a framework on top of it. For dashboards, internal tools and applications behind a login, React as a single-page app is usually enough. If content should be visible in Google or in AI search, we recommend Next.js: server rendering and static generation deliver finished HTML, and the components stay the same.
Can you migrate an old frontend to React step by step?
Yes. Because React consists of components, we replace individual areas of an old frontend one after another while the rest keeps running. We start where changes cost the most time today. The application stays shippable throughout.
Do you take over existing React codebases?
Yes. We start with a code review: state of dependencies, test coverage, performance. You then get a prioritised list and decide what comes first – outdated libraries, missing tests or individual slow views.
What does a React agency cost?
That depends on the billing model and scope. The main cost drivers are the number of views and states, the interfaces, a custom design system and the requirements for tests and performance. Our project calculator gives you a first range; a binding offer follows after the workshop.
Sources
As of October 2026
Your edge with React
React is the most widely used UI ecosystem – that protects your investment and makes hiring easier. We use it pragmatically rather than chasing every trend.
Experience with large, growing codebases
Accessible and high-performance components
Clear separation of UI, logic and data
Measurable improvements to interactivity (INP)
React, Next.js or Angular?
For new web frontends the choice is often between React, Next.js and Angular. Which base fits depends on rendering needs, SEO, team size and maintenance horizon – a rough guide to help you decide, not a binding verdict.
| Criterion | React | Next.js | Angular |
|---|---|---|---|
| Rendering | Client-side (SPA), SSR only with extra tooling | Server rendering, static generation and streaming built in | Client-side, SSR included in the framework |
| SEO / SSR | Only with additional setup | Core feature, finished HTML for crawlers | Possible, but rarely the main reason to choose it |
| Learning curve | Gentle, a library rather than a framework | React knowledge plus routing and rendering concepts | Steeper, many concepts from day one |
| Structure & conventions | Free, the team defines the architecture | File-based routing sets a basic structure | Fixed: modules, DI, router, forms |
| Ecosystem | Very large, many libraries to choose from | Builds on the React ecosystem | More closed, much is included in the framework |
| Typical use | Dashboards, configurators, interactive widgets | Marketing sites, shops and portals that need SEO | Large business applications with many forms |
Common market view, as of 2026 – not a binding verdict. We work out what fits your project after a look at rendering needs, team and maintenance horizon.
Read on and check
Project calculator
A first cost range for your React project.
Single-page application
What an SPA is and when it fits.
Hydration
How server HTML becomes an interactive interface.
Angular, React or Vue?
The detailed comparison for shop frontends.
Web applications
Our service for portals and internal applications.
Ready for your React project?
Let's talk about your requirements – we'll get back to you within 24 hours with concrete next steps.
React Data & Insights
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