Next.js App Router applications
Server Components, Suspense streaming, parallel + intercepting routes, on-demand revalidation, edge middleware.
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Senior engineering · React
Senior React engineering for production systems.
Senior React engineering — App Router and Server Components, design systems that don't drift, accessibility-first interfaces, and bundle budgets defended at every release.
- In production
- 2018+
- Senior bench
- 70+ G6/G9 engineers
- Floor
- G6+ on client work
- Engagement
- Outcome-led, not hourly
Why senior, not contractor
React in production is a different problem than React on a laptop.
React is everywhere, but production-grade React is rare. Most teams ship a tangle of `useEffect` hooks, prop-drilling that should have been context, components nobody can refactor without breaking three pages, and a bundle that's 4x what it should be. Prosigns ships React with the architecture, accessibility, and performance discipline that survives the third year of feature work — not just the first.
Senior floor
G6+ minimum
Bench depth
70+ G6/G9 engineers
In production
2018+
Engagement
Outcome-led SOW
Where React ships
6 sub-areas, grounded in shipped engagements.
Specific applications of React we’ve built and operate. Every example below maps to a real engagement, not a bullet on a stack-card.
01 02 Design systems + component libraries
shadcn/ui, Radix, Headless UI, Tailwind. Tokens, theming, accessibility primitives, Storybook regression suite.
03 State management beyond useState
Tanstack Query for server cache, Zustand / Jotai / Valtio for client state, React Hook Form for forms. Right tool, right shape.
04 Accessibility + WCAG 2.2 AA
ARIA done correctly, keyboard navigation that works, screen-reader testing, axe-core in CI. Real accessibility, not vendor checkbox.
05 Performance engineering
Core Web Vitals, bundle budgets, code splitting, image optimization, font subsetting. Lighthouse > 95 defended in CI.
06 Replatform off legacy React
Migration from CRA / Webpack / class components / Redux saga onto Next.js App Router with phased component-level cutover.
Stack depth
The React ecosystem, owned.
Frameworks, libraries, and runtime tools the bench has shipped in production. Not a CV-skim — a working depth.
Frameworks
- Next.js
- Remix
- Vite + React Router
- Tanstack Start
UI primitives
- Radix
- Headless UI
- shadcn/ui
- Aria Components
- Tailwind
State + data
- Tanstack Query
- Zustand
- Jotai
- Valtio
- Redux Toolkit
Forms + validation
- React Hook Form
- Zod
- Conform
- TanStack Form
Quality + perf
- Vitest
- Playwright
- axe-core
- Lighthouse CI
- Storybook
Engagement models
Three ways to engage React engineers.
We don’t bill hourly contractors. Engagements run against outcomes — choose the shape that matches the work.
See engagement models- 01
Fixed-scope
Defined deliverable, fixed price
When the deliverable is clear and the scope is bounded — an MVP, a migration, a discrete platform build. Senior engineering against a written outcome, not against a body count.
- 02
Embedded squad
Senior product team, ongoing
When the work is product-shaped and the cadence is continuous. A senior pod (engineering + design + PM as needed) embedded into your team, with the practice lead co-piloting from HELM.
- 03
Managed services
Steady-state operations
When the system is running and needs ongoing engineering ownership — operations, SLO defense, release management, security and compliance evidence. Monthly retainer against a published SLA.
Selected work
React engineering that shipped.
Healthcare
Clinician-facing rounding interface for a 14-hospital system.
99.4%crash-free rateReact + Next.js App Router with SMART-on-FHIR launches into Epic. Offline-first with service-worker sync. Survived hospital MDM rollout and the first 60-day audit cycle.
Duration · 9 months
Brief us
Reply < 4 business hoursHave a React workload? Send a brief.
Five fields. Goes straight to the practice lead — not an SDR. We’ll reply with a senior engineer’s read on fit, scope, and the engagement model that suits the work.
FAQ
Questions buyers ask.
Everything below also appears in the proposal and the SOW — no surprises after signing.
App Router or Pages Router?
App Router for new builds. Pages Router for legacy maintenance and apps where the migration cost outweighs the benefit. We'll assess and tell you honestly which fits.
What's your stance on client-side rendering vs RSC?
RSC by default for server-rendered shells; client components scoped narrowly to the interactive surfaces that need them. The opposite of the everything-is-client-component pattern that defeats the point of the App Router.
Is this staff-aug, or is it engineering-led delivery?
Engineering-led delivery. We don't bill hourly contractors against your JIRA board. Every engagement runs against a defined outcome with a senior engineer accountable from kickoff to operating cutover. If you genuinely need staff-aug — discrete bodies, your management, hourly rates — we'll be honest and route you to a partner that fits.
What seniority floor are we talking about?
G6 minimum (six-plus years in their craft) on every billable hour. Department leads are G9 or G10. We don't flex juniors onto the bench mid-sprint, we don't subcontract to delivery centers, and we don't dilute senior rates with mixed staffing. The bench in the proposal is the bench in production.
How does pricing work?
Three engagement models published at /engagement-models/. Fixed-scope for defined deliverables, embedded squads for ongoing product work, managed services for steady-state operations. Rates depend on seniority, engagement length, and region. Discovery + scoping conversation is free; SOWs are written against deliverables, not bodies.
Where are your engineers based?
Senior-only across Dallas, Doha, Lahore, and Islamabad. We staff against the engagement's needs (timezone, language, regulatory frame), not against arbitrary regional preferences. Most engagements run with a US/EU-aligned core and a follow-the-sun extended bench when the workload warrants it.
Will the engineers I see in the proposal be the engineers shipping the work?
Yes. We name the engineers in the SOW, attach their profiles, and they're on the kickoff. We don't bait-and-switch with senior reviewers and junior execution. If a named engineer needs to roll off the engagement (rare), we surface a replacement from the same seniority tier with explicit handoff.
Talk to a React lead
Senior React engineering, accountable from kickoff.
Bring the workload — we’ll bring a senior engineer plus the practice lead most relevant to the work. 30 minutes, no obligation, no junior reps.