Next.js development for new and existing applications
For agencies and product teams that run Next.js or have chosen it. We join your codebase, modernise it and keep building features.
Why this approach
Join your codebase
We work in repositories that other teams started, and we keep to the conventions already there. New code goes through your normal review.
Move to the App Router
We move Pages Router applications to the App Router in steps, route by route. You keep releasing while the move happens.
Rendering and performance
We choose server rendering, static pages or caching per route, and we cut JavaScript that slows pages down. We measure before and after each change.
Ongoing development
Most clients keep working with us on new features and upkeep. Framework upgrades and dependency updates are part of that work.
Stack
- Next.js
- App Router, Pages Router, rendering and caching
- React
- Server and client components
- TypeScript
- Typed code from data to page
- Node.js
- APIs, route handlers and integrations
- Sanity
- Headless CMS for site content
- Azure
- Cloud hosting and services
Process
- 01
Share the codebase
Tell us about the application, its Next.js version, what you need delivered and your timing. We reply with questions or a time to talk.
- 02
Review and plan
We read the code, run the build and check the slowest pages. You get a written plan with the order of work.
- 03
Change in small steps
We ship small pull requests through your review process. Each week ends with a short demo of software that runs.
- 04
Keep building
Documentation, access and a walkthrough are part of the plan. Most clients keep working with us on new features and upkeep.
Questions
Can you join an existing Next.js application?
Yes. We work in repositories that other teams started, and we keep to their conventions. We start by reading the code and running the build, then agree who owns which part.
Can you move our app from the Pages Router to the App Router?
Yes. Next.js runs both routers side by side, so we move routes in steps instead of rewriting everything at once. We agree the order with you, and you keep releasing during the move.
Can you help with a slow Next.js site?
Yes. We look at rendering, caching, JavaScript size and data fetching per route, then fix the causes one by one. You can hire us for this work without a rebuild.
Do you also connect a CMS or a commerce platform?
Yes. For content we integrate Sanity, and for shops we build headless commerce on Shopify or MedusaJS. House of Massive and Samphire both run on Next.js.
How is this different from your full-stack web development service?
This page is for teams that run Next.js or have chosen it. If you need a team for a complete build, see full-stack web development. For advice or a development lead, see web development consultancy.
How do we start?
Use the contact page or write to hi@adeptive.se, in English or Swedish. Tell us about the application, its Next.js version and what you need delivered. We reply with our questions or a time to talk.
Read next
- Search Integration for MedusaJS + Next.js + Sanity: Scoring, Ranking & RelevanceSearch is not a plugin. It is a system. Here is an engine-agnostic playbook for building fast, relevant ecommerce search in a MedusaJS + Next.js + Sanity Mar 6, 2026
- Headless E-commerce with Sanity, Next.js, MedusaJS, and Stripe (A Practical Build Guide)Headless commerce is a way to ship faster, scale without rewriting, and avoid platform lock-in. Feb 28, 2026
- App Router vs Pages Router: What We Actually Use in ProductionWe have shipped Next.js projects on both routers. Here is what we actually pick for production work and why the answer is not always App Router.Feb 23, 2026
What does your Next.js app need?
Tell us about the application, its Next.js version and what you need delivered. We reply with our questions or a time to talk.