React apps that load fast, scale clean, and your team can actually ship on.

Yes — roughly 35% of our React work is built for other agencies, product studios, and consultancies under NDA. Three partnership models: white-label (your brand, our engineers, fully invisible), agency-of-record (a dedicated React pod working as your in-house capacity), and capacity overflow (sprint-by-sprint engagement when your in-house team is full). Code ownership transfers to your repos. Time zones overlap with the UK, EU, and US workday.

Our entire React engineering team is based in Noida, India — 40 people in our iThum Tower B office, founded in 2015. We work with product teams and agencies across the UK, US, Ireland, Australia, the UAE, Germany, and the Netherlands. Working hours overlap with UK mornings (your 9 AM to noon), the full EU workday, and US afternoons (your 1 PM to 6 PM EST). For agency partners we run in their tooling — Slack, Jira, Linear, ClickUp, Asana — as standard.

Next.js for anything customers find through Google (marketing sites, content engines, e-commerce, product pages) — SSR and Server Components are not optional when SEO matters. Vanilla React with Vite for logged-in product applications (SaaS dashboards, internal tools, real-time interfaces) where the UI is the product and SEO does not matter. Most applications need one or the other, not both; picking the wrong stack is the most expensive React architecture mistake we see.

Custom React builds range from small marketing sites through to enterprise SaaS applications and headless commerce frontends. The right scope drivers are application complexity, custom functionality, integrations, performance targets, and the team’s React maturity. We scope every engagement against the specific brief and are honest about which features can wait until phase two.

A typical custom Next.js marketing site takes 6 to 10 weeks. A SaaS dashboard or product application takes 10 to 16 weeks depending on feature scope. A headless commerce frontend with Shopify or another headless CMS takes 8 to 14 weeks. Migrations (CRA to Vite, Pages Router to App Router) typically add 4 to 12 weeks depending on app size. We work in two-week sprints with weekly demos throughout.

Yes — every React build we ship hits sub-1.5-second LCP, sub-0.05 CLS, INP under 100 ms, and a Lighthouse mobile score above 90. We achieve this through proper code splitting, Server Components where appropriate, AVIF / WebP images with responsive srcset, deferred third-party scripts, profiled render performance, and initial JavaScript bundles under 150 KB gzipped. Performance is part of the build, not an afterthought.

For new Next.js builds in 2026, App Router is our default — smaller client bundles via Server Components, cleaner data fetching, streaming, and Server Actions. For existing Pages Router apps that work well, we maintain them on Pages Router and migrate only when there is a specific reason (planned features that benefit from RSC, performance walls, or rebuilds happening anyway). We will tell you honestly which router fits your project.

Yes. WCAG 2.2 AA is our baseline on every React build — colour contrast checked per token, full keyboard navigation tested, screen-reader landmarks audited, focus management on modals and dialogs, ARIA used correctly and minimally. We use Radix, React Aria, and Shadcn UI as primitives that get accessibility right by default. Accessibility is part of the build, not a fix after launch.

Yes. We have built headless storefronts with Shopify Hydrogen + Oxygen, Sanity-driven content sites, Contentful-driven marketing sites, and custom GraphQL backends with Next.js. Headless commerce is one of our specialities — see our Shopify Development page for the deeper take on Hydrogen vs standard Shopify, and our content cluster on App Router vs Pages Router for the Next.js-specific architecture choices.

Yes. We offer monthly React maintenance retainers covering dependency updates (React, Next.js, third-party libraries), security patches, Core Web Vitals monitoring, accessibility regression checks, bundle-size monitoring, error monitoring (Sentry or equivalent), and a fixed allocation of editorial and development hours. For product teams without a dedicated React engineer in-house, this is how the app stays healthy past month one.

Yes. CRA to Vite migrations are typically 1 to 3 weeks and yield 20 to 40% performance improvement before any other work. Pages Router to App Router migrations are 4 to 12 weeks depending on app size and complexity. Vanilla React to Next.js migrations are 6 to 16 weeks — effectively a rebuild of the routing and data-fetching layers while preserving component code. We have done each many times; we will tell you on the discovery call whether migration is the right call or whether optimising what you have makes more sense.

Yes. We routinely inherit React projects mid-build — codebases left by a previous agency, internal projects that stalled, MVPs from the founder’s first engineer that need to be scaled up. We start with a code audit (architecture, performance, accessibility, dependency health, test coverage), present a written report with a salvage-vs-rewrite recommendation, then either improve or rebuild based on what serves the business. Most inherited projects are salvageable.

Our default 2026 SaaS stack: React 18+ with TypeScript, Vite (or Next.js if SSR is wanted for marketing surfaces), TanStack Router or React Router, TanStack Query for server state, Zustand or Jotai for client state, Radix UI or Shadcn for accessible primitives, Tailwind for styling, Vitest + React Testing Library + Playwright for testing, deployed to Vercel, Cloudflare Pages, or AWS depending on infrastructure preference. We adjust based on the team and the requirements but the stack above is what we recommend by default.