Best agency for modern web development: Next.js, Astro and headless CMS

Is there even a single best agency for modern web development?

No, and in the technical field the question is put even worse than in design. Web development is not a single trade. An agency that builds excellent marketing websites with Astro and a headless CMS is not automatically the right one for an application with user accounts, roles and real time data. And a team that maintains Angular enterprise applications will over-engineer your content site.

So the first question is not who the best provider is but what kind of project you actually have. Roughly, there are three cases. First the content driven website: marketing pages, landing pages, blog, many editors, high demands on load time and visibility. Second the application in the browser: dashboard, portal, configurator, login area, state and logic in the frontend. Third the mixed case, where a public site and a logged-in application live under the same domain. Each of these three cases has a different sensible stack and a different kind of team.

Rankings hardly help with that. Most lists of Next.js agencies are written either by one of the listed agencies or by a platform that brokers leads. They are useful as a source of names. You make the selection yourself afterwards, against checkable criteria.

How do you recognize an agency that can really build?

Eight criteria separate a team that develops from one that configures templates. All eight can be asked about in a single conversation, and the answers are rarely a matter of interpretation.

1. Bespoke code instead of builder configuration

The difference shows in a single question: how would you build a function the system does not have. A team that develops describes a component, an interface and a test. A team that configures looks for a plugin or explains why the function is not necessary.

That is not a judgment against site builders. For many sites a well maintained system is the more sensible choice because it is faster and cheaper and the client can carry on working with it later. It becomes a problem when the boundary is concealed and you only notice during the project that the one function you chose the agency for cannot be done cleanly in this system.

A practical test: ask to see a public repository or a code excerpt from a real project. Not to assess the code but to see whether there is any. At a web development agency that should be one of the easiest questions of the conversation.

2. Framework choice with a rationale: Next.js, Astro or Webflow

A good agency does not propose a framework before it knows what the site is supposed to do. And it can justify the choice in two sentences, including the drawbacks.

Next.js is the right answer when interactivity, user accounts, dynamic data or an application are involved. It brings server rendering, routing and a large ecosystem, and costs complexity in build and operations while requiring a team that really knows React. Astro is the right answer for content driven sites that mainly need to be fast. By default it ships no JavaScript and loads interactivity only where it is needed, which shows directly in the load times. Webflow is the right answer when there is no developer team in house, the scope stays manageable and marketing should be able to build pages itself. The price for that is platform lock-in and limits on bespoke logic. And Angular mostly turns up in grown enterprise applications, more rarely in new website projects. If an agency proposes Angular for your marketing project, ask for the reason, there can be one but it has to be justified.

The detailed comparison of the systems is in our piece on Webflow, Wix Studio and Next.js. The warning sign in a conversation is simple: if the answer to every project description is the same framework, you are not hearing a recommendation but a habit.

3. Headless CMS: who maintains the content in the end?

A headless CMS separates content from presentation. The content sits structured in a system such as Sanity, Storyblok, Contentful or Strapi and is delivered through an interface, to a website, an app or both. For developers that is liberating. For editors it is a step backwards precisely when nobody has designed the editing interface.

This is exactly where many headless projects fail. The stack is clean, the site is fast, and then it turns out that the marketing colleague has to fill in fourteen individual fields for a new landing page without seeing what the result looks like. So ask concretely: what does the preview look like, how does someone create a new page, which roles and approvals exist, and who sets up the content models. With Sanity the studio can be fully customized, which is half the value of the system and often gets left out.

The second question concerns migration. If you are coming from WordPress or TYPO3, importing the existing content is often more effort than the rebuild. Have them describe how the migration runs and who is responsible for data quality.

4. Performance budget and Core Web Vitals as an acceptance criterion

Performance is the only quality attribute of a website that can be agreed as a number before launch. Use that. The three Core Web Vitals values are publicly defined: LCP under 2.5 seconds, INP under 200 milliseconds, CLS under 0.1. Write them into the proposal, with the measurement method and the point in time.

A performance budget goes one step further and defines up front how much the page may weigh: an upper limit for JavaScript, for images, for third party scripts. That sounds bureaucratic but it prevents exactly the course almost every project knows. At the start the page is fast, then tracking, a chat widget, a consent banner, a video in the hero and one more font family are added, and in the end nobody discusses load time any more because the budget was blown long ago.

Three questions that separate the field in a first conversation: do you measure lab or field data. How do you handle third party scripts that marketing adds later. And what happens if the target values are not reached at acceptance. How to read the values yourself is in the article on Core Web Vitals.

5. Code handover and repository ownership

This is the point where most contracts stay silent and most separations get expensive. Clarify in writing before signing: who owns the repository, who holds the hosting and CMS accounts, under which license the written code sits, and whether you can deploy yourselves at any time without asking the agency.

The clean state looks like this: the repository sits in your GitHub or GitLab organization and the agency works in it as a contributor. Hosting, domain and CMS run on your accounts, the agency has access, not ownership. And there is a file in the project describing how a new developer starts and ships the project locally. If these three points stand, changing agency costs time but not the project.

The unclean state is more common than one thinks: repository at the service provider, hosting under their bulk contract, no documented build. That is rarely bad intent, more convenience on both sides. It still becomes a problem as soon as someone wants to leave. Ask early and in writing, the conversation is over in two minutes and may save you a five figure sum.

6. Accessibility and the German accessibility act

Since 28 June 2025 the Barrierefreiheitsstärkungsgesetz has applied in Germany, the national implementation of the European Accessibility Act. It obliges providers of certain consumer facing services to make their digital offerings accessible, including online shops, banking services, passenger transport and e-books. Micro enterprises are exempt for services, and pure B2B offerings do not fall under it.

For agency selection that means two things. If your offering is affected, you need a team that has practical command of WCAG 2.1 level AA, not one that merely quotes it. Ask about concrete things: contrast ratios in the design system, keyboard operation without a mouse, focus indicators, form errors a screen reader also announces, and alternative text as a required field in the CMS. And if your offering is not affected, it is still worth it, because the same measures make the site more usable for everyone and more readable for search engines. What the law requires in concrete terms is written up in our article on the accessible website under the BFSG.

7. Maintenance and further development after launch

A modern web application is not a piece of furniture you set up once. Dependencies get security updates, frameworks release major versions, browsers change behavior, and your own requirements grow. Whoever agreed nothing after launch stands a year later in front of a project nobody wants to touch any more.

So clarify three things up front. First: who updates dependencies and at what rhythm, and is that included in the price or a separate line item. Second: how fast does the agency respond when the site goes down, and is there a written commitment for that. Third: how are small changes handled, by ticket, by an hour contingent or as monthly support. That sounds banal but it decides whether a site is still current after two years or whether the next relaunch is already due because nothing happened in between.

A warning sign is a proposal that ends with the launch and afterwards only foresees an hourly rate list. It is not wrong, but in practice it often means nobody has reserved time for you after launch.

8. Specialist instead of full service

A team that builds websites and web applications every week has seen more cases than one handling the same task between two campaigns. That applies even more technically than in design, because frameworks, build tools and browsers change faster than design trends. Whoever does not build continuously works with the state of two years ago.

At INSYNC there are two lanes: web design and web development on one side, SEO and GEO on the other. Those are technically connected because rendering, structure and load time directly influence how a page is found and cited in AI answers. We do not do performance marketing, social media management, print or trade fair construction.

The other side belongs here: if your need goes beyond the website, if you need a campaign across several channels, ongoing social content or media buying, a full service agency is the better address because everything runs under one roof and one budget. And if your project is real software with a complex backend, data model and operations, you need a software house rather than a web agency. That is part of an honest classification too.

How to find the right agency for you

The eight criteria turn into a decision once you apply three filters: your goal, your budget and your industry.

By goal

If the goal is a fast, easily findable marketing site, look for a team with Astro or Next.js experience and a clean CMS concept. Rendering and the content model matter more here than any backend competence. If the goal is an application with login, roles and data, you need a team that can talk about state management, authentication and API design and writes tests. If you are migrating, moving from WordPress or TYPO3 to a modern stack, experience with redirects, content import and preserving existing visibility counts more than anything else. And if you need both, a public site and a logged-in application, ask early about the domain and deployment architecture, that is the decision most expensive to correct later. For software vendors we described the typical requirements in the article on the SaaS website.

By budget

Individually developed websites realistically start at around 6,000 euros, and in that range we are talking about a compact presence with a clear structure. Between 8,000 and 15,000 euros lies the range where a modern stack with a headless CMS, several page types and a clean editing interface come together. From 15,000 euros multiple languages, extensive integrations, a design system or a motion layer are added. All tiers are openly listed on our pricing page.

With applications instead of websites the calculation shifts. There you do not pay for pages but for scope of functionality, and a fixed price is rarely sensible. Common practice is a paid concept phase, then implementation in increments with fixed capacity. Whoever quotes you a fixed price for a complex application without a concept phase has either buffered generously or will ask for more later.

By industry

Software and SaaS companies need a team that understands pricing logic, trial or demo flows and the connection to signup and CRM, and that can write for a technically versed audience. Industry and mechanical engineering usually bring multiple languages, large product structures and data imports from PIM systems, where experience with structured content counts more than design awards. Retail needs commerce experience, which is a field of its own and is rarely covered as well by the same agency as a marketing site.

And if your project is mainly ambitious in design terms, with its own motion layer and a strong brand presence, then the development question is only half the question. The design side belongs to it, meaning individual web design with its own concept, which we cover in the article on the best web design agency in Germany. How far a dedicated animation layer can go technically is shown in our piece on vector based animation flows, and the service itself is on the motion design agency page.

Provider overview: agencies for modern web development 2026

This overview is not a ranking but a cross section. Five German providers with a visible focus on modern frontend technology or headless architectures, so you can see how differently the market is cut. We opened each website ourselves on 9 September 2026 and state exclusively what is written there: location, focus and technology according to their own presentation. We do not name third party prices because they are not publicly verifiable.

The market is narrower in this niche than in web design generally. Many German agencies list Next.js in their technology directory without a recognizable focus. The providers named here have a visible, stated focus. INSYNC appears in the list itself, sorted alphabetically and not in first place.

happycoding

According to its own site, happycoding is a software and web agency from Berlin and a brand of Radscheit GmbH. The focus is clearly stated on the homepage: TypeScript, Next.js, Sanity and process automation for small and medium sized companies as well as corporates in the DACH region and Scandinavia. The agency names over 150 completed projects, 15 years of experience and a team of eight senior level people. Cases named include Tree Energy Solutions. If you are looking for exactly the Next.js plus Sanity combination and prefer a small, senior team to a large apparatus, you will find a fitting profile here.

INSYNC

That is us. INSYNC builds websites and web presences with Next.js or Astro and Sanity as the headless CMS, and Webflow is possible as an option when a client without a developer team wants to carry on themselves. On top of that comes a dedicated motion and 3D layer that we treat as part of development, not as later decoration. The second lane is SEO and GEO, meaning visibility in search engines and in AI answers. Our prices are open, from 6,000 euros for a one-pager to 15,000 to 30,000 euros for a premium project. The location is the Upper Palatinate, the team works internationally.

What we are not the right choice for: we are not a software house. If your project is a complex backend with its own data model, operations and support organization, you need a different team. No performance marketing, no social media management, no print, no trade fair construction. And we do not work with WordPress as a default, so anyone who deliberately wants to stay with it is better served elsewhere. An example for the other direction: for Silencio Network we rebuilt the site before the seed round, it reached over 200,000 visitors and accompanied a funding round of 2.5 million USD, as described in the piece on the Silencio funding round.

kernpunkt

kernpunkt describes itself on its own site as an e-commerce agency from Cologne with a clear focus on composable and headless commerce, replatforming, PIM and DXP consulting as well as system architecture. Partner technologies named include commercetools and Akeneo. In 2026 the agency positions itself strongly around AI supported project delivery and has published its own study on it. The profile fits when shop, product data and adjacent systems are the actual project. For a pure marketing website without a commerce share, the profile is larger than necessary.

Neoskop

According to its own presentation, Neoskop is an owner led digital agency from Hanover working since 2010. The expertise page is structured into strategy, creation and technology, and under technology it lists frontend applications, enterprise platforms, performance and accessibility as well as DevOps and Kubernetes. Clients listed include VHV Versicherung, Hannoversche, enercity and Windwärts. It is notable that performance and accessibility are named as a competence of their own, which rarely happens explicitly in this market. A fit for larger platform projects with a long horizon, less so for a compact company site.

TJ Labs

TJ Labs UG is based in Berlin according to its legal notice and runs a dedicated page on Next.js where it describes itself as a Next.js agency for web apps. Named there are App Router, React Server Components, server side rendering, Edge and TypeScript, plus Core Web Vitals as an explicit goal. The agency states it has developed more than 30 digital Next.js products. The described focus visibly sits on applications such as booking, sales and real estate platforms with dashboards and user accounts, less on classic marketing presences.

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