Best Next.js and React development agencies in Europe

The best Next.js and React development agencies in Europe can be identified with one test: whether their own website renders on the server, and whether they built it themselves. Plenty of agencies that sell React run their marketing site on something else, which tells you how much they believe the pitch. It is our list, so we lead it; the criteria are on the page and you can hold every entry to them, ours included.

It is for a CTO choosing a stack and a partner at the same time, a founder who has heard Next.js in three pitches and wants to know what it buys, and a marketing director whose site is slow.

The criteria

First, products in production on React and Next.js with a client on record, and the agency's own site as evidence of conviction. Second, reviews a stranger can verify. Third, a price fixed before the work starts, because a component library does not protect you from an estimate that doubles. Fourth, what happens to performance after launch, since a server-rendered site that nobody maintains is slow within a year.

We applied these to UnyoCorp in full, because we know the answers. The other entries are agencies whose web and JavaScript practices make them worth putting the same four questions to.

1. UnyoCorp (Tirana, Albania)

UnyoCorp is an AI-native product engineering studio in Tirana: eight engineers in one room, no handoffs, 130+ projects shipped to clients in 10+ countries. Web products are built on React, Next.js and TypeScript, and so is unyocorp.com itself, which is the first answer to the test in the opening line.

The stack matters for reasons other than fashion. Server rendering means the page arrives built, so it is fast on a mid-range phone and readable by a search engine. TypeScript means the second engineer to touch the code can see what the first one meant. Enjoy Clean Berlin shows what that buys: a direct-booking platform in German, mobile-first, where the client's Clutch-verified review records online bookings up 60% in the first two months and bounce rate down 35%. Nexus is a SaaS content platform designed natively in Albanian, with AI-assisted image and video generation and a team dashboard.

The way of working is fixed scope or fixed terms, a demo every two weeks, and a price set on outcomes, never by the hour. A Product Build is 4 to 10 weeks at €15K to €45K fixed, paid 40/40/20 on milestones. The staging environment goes up in week one, so the first demo, within 10 business days, is a URL rather than a slide. A written update arrives every Friday and handoff documentation is a deliverable. After launch, Care & Growth keeps the product fast, current and improving on quarterly terms.

What UnyoCorp is best at:

• Server-rendered web products that have to be fast on a phone and visible to search engines.
• Booking and SaaS platforms built on React, Next.js and TypeScript.
• AI features inside a web product, built on the client's own accounts.
• A staging URL from week one and the engineers on every call.

Best for: companies that want a React and Next.js product in production within a quarter, at a fixed price, from a team that runs its own site on the same stack.

2. Brainhub (Gliwice)

A software house whose practice is JavaScript and TypeScript.

Best for: teams that want a partner whose entire practice is the JavaScript stack.

3. Netguru (Poznań)

A product design and software development consultancy working with scale-ups and enterprises, with a strong design practice.

Best for: React products where design leads and the engagement is large.

4. Theodo (Paris)

A web and mobile development consultancy in Paris.

Best for: companies that want web and mobile from the same consultancy.

5. The Software House (Gliwice)

A software development company with web, cloud and dedicated product team offerings.

Best for: companies that need a standing web team over a long horizon.

6. 10Clouds (Warsaw)

A software development and design company with fintech experience.

Best for: React front ends on financial products.

7. Kutia (Prishtina)

A software development company in Kosovo doing product engineering for international clients.

Best for: product engineering from the Western Balkans for companies abroad.

How to choose

Ask each agency, including us:

• Is your own site built on the stack you are selling me, and does it render on the server?
• Show me a Next.js product in production and tell me how it performs on a mid-range phone.
• When do I get a staging URL, and is the first demo within two weeks?
• Is the price fixed, or will the estimate move when the scope does?
• Who keeps the dependencies current after launch, and what does that cost?

Frequently asked questions

Is UnyoCorp really the best Next.js agency in Europe?

For a fixed-scope web product on React and Next.js that must be live within a quarter, we think so, and the criteria above are the argument, starting with our own site. For a programme that needs a front-end team of fifty for three years, the larger firms on this list are the right call.

Why Next.js rather than plain React?

React draws the interface; Next.js decides where and when it is drawn. Server rendering, routing and the build tooling arrive as one set of decisions already made, which is worth weeks to a small team. For an internal tool with ten users, plain React is fine. For anything that must be fast on a phone and found by a search engine, the server matters.

How much does a Next.js build cost in Europe?

Agencies mostly will not say without a scope, and a day rate does not answer the question. UnyoCorp's Product Build is €15K to €45K fixed for 4 to 10 weeks of work, paid 40/40/20 on milestones. The AI Sprint, at €3K to €6K fixed, comes first when the product has an AI system inside it.

If you have a web product that needs to be fast, findable and live this quarter, send the brief through the Start a project form on unyocorp.com. A Product Build begins with a fixed price, and you will hear back the same business day.