Written React architecture audit and migration plan. CRA to Vite, Redux to Zustand, React 17 to 19. Optional hands-on implementation.
- Audit
- Architect
- Scale
monthly retainer
Who this is for
You're a CTO sitting on a React codebase that hasn't been modernized since 2020. The team debates CRA to Vite, Redux to Zustand, React 17 to 19, or a full App Router migration — but nobody has shipped one of these at scale before. You need a written plan before you can commit budget or sprint capacity to it.
The pain today
- Nobody on the team has actually shipped a large React migration end to end.
- Leadership wants a written plan with hours and risks before committing budget.
- The dev server starts in 45 seconds and the bundle ships half the internet.
- Class components, three state libraries, and zero memoization strategy — all in one codebase.
- React Server Components keep coming up in planning but nobody knows if the app is ready.
The outcome you get
- A written React architecture audit with categorized findings and hours to fix each.
- Phase-by-phase migration schedule your team can execute without me in the room.
- A state-management decision document: Zustand vs. TanStack Query vs. Context, with a recommendation.
- RSC-readiness score: what percentage of the UI could become Server Components today.
- Optional implementation follow-up at the Applications rate — audit is useful standalone.
What the React audit finds
I've run React audits across codebases from 10k to 300k lines, and the same five categories show up every time.
Re-render hotspots: components that fire on every parent update because of unstable prop references or missing memoization. In a medium-sized app, fixing the top ten re-render chains can cut interaction latency by a third without touching a single feature.
Bundle bloat: whole-library imports instead of tree-shaken ones, duplicate versions of the same package in node_modules, dev dependencies in the production build. These are invisible until you run a bundle analyzer, then they're embarrassing.
State fragmentation: three libraries managing state in one repo, local state that leaked into global, server state in Redux instead of TanStack Query. This is the most expensive one to fix because it touches every layer.
A11y gaps: missing ARIA labels, broken focus traps, semantic HTML replaced by divs. These also create legal exposure.
RSC-readiness: for teams moving toward Next.js App Router, I score how much of the component tree can become a Server Component today — and what needs to change first. At bolttech, I worked across a React plus NestJS codebase supporting 40+ payment provider integrations and 99.9% uptime. That experience shapes what I look for: the gap between what the app does under load and what it would do at 10x scale.
Every finding in the report comes with an effort estimate in hours.
A written React architecture audit with categorized findings and hours to fix each.
Sample CRA-to-Vite migration plan
CRA-to-Vite is a three-phase job, not a weekend task.
Phase 1 (1-2 weeks): replace react-scripts with Vite, fix VITE_ env var prefixes, update path aliases, update index.html location, smoke-test the full app. This phase breaks things in predictable ways — the audit documents which ones before a single line changes.
Phase 2 (1-3 weeks): migrate the test runner from Jest to Vitest where it makes sense, fix Babel-specific transforms, update CI pipelines. Some teams skip Vitest and stay on Jest with vite-jest. I recommend based on test suite size and coverage gaps found in the audit.
Phase 3 (1-2 weeks): optimize the production build, add route-level code splitting, set a bundle-size CI gate so the bundle never regresses. Total: 3 to 7 weeks depending on codebase size, test coverage, and how many Babel transforms are in play.
The same phased structure applies to Redux-to-Zustand and React 17-to-19 migrations. Each gets its own plan in the audit document.
40+: Payment providers integrated.
React Server Components readiness check
React 19 and Next.js App Router change the mental model more than any React release since hooks. Most teams aren't ready — not because the technology is too new, but because their component architecture was written for a client-only world.
I score readiness on three questions. First: how much of your data fetching lives in components via useEffect versus in loaders or layout routes? Client-side data fetching is the main blocker for RSC adoption. Second: how many components rely on browser-only APIs (window, localStorage, IntersectionObserver) without a server-safe fallback? Third: what percentage of your components hold no state at all and could run on the server without modification?
The readiness score tells you whether an App Router migration is a 6-week job or a 6-month refactor. I've seen both, and the difference usually comes down to whether someone audited the component tree before committing to the migration timeline.
For reference: Instill runs React 19 plus Next.js App Router at production scale, with 30+ active users and an MCP server architecture. I built it from scratch with RSC constraints in mind from day one. That gives me a concrete comparison point between a greenfield RSC project and a mature codebase migrating toward it.
Pricing and what you get
The advisory engagement runs $5,499 per month, pro-rated for a 1 to 4 week scope. That covers the written audit report, a migration plan with phase-by-phase hours and risks, a debrief call with you and your team, and a 2-week follow-up call to answer questions as implementation starts.
If you want me to execute the migration, the Applications subscription at $4,999 per month covers implementation. Most teams do the audit first and decide after seeing the scope.
The audit is worth having even if a different engineer implements. You get a document your team can follow, a second opinion before committing months of sprint capacity, and a reference when new engineers join the codebase. The 14-day money-back guarantee applies to all advisory engagements — if the audit doesn't surface anything useful in the first two weeks, you don't pay.
Recent proof
A comparable engagement, delivered and documented.
Unified payment orchestration across Asia and Europe
Delivered the payment orchestration platform at bolttech, a $1B+ unicorn, with 40+ integrations across multiple regions.
Read the case studyKeep reading
Frequently asked questions
The questions prospects ask before they book.
One to four weeks depending on codebase size. A 50k-line app with reasonable test coverage takes about two weeks. A 200k-line monorepo with multiple apps sharing components takes four. I scope it precisely after an async repo walkthrough before you commit to the engagement.
An audit produces a written plan — findings, prioritized fixes, migration phases, and hours. A developer executes. Most teams need the audit first so they know what they're actually buying when they hire someone to implement. The audit also functions as a second opinion if your team has already formed a plan internally.
Yes. RSC-readiness is a standard section of every audit: component tree analysis, data-fetching patterns, browser-API dependencies, and a migration path if App Router is the goal. I built Instill on React 19 and Next.js App Router from scratch, so this isn't theoretical.
No. React Native is outside my core stack. Web React on Vite, Next.js, Remix, CRA, and Gatsby — yes. React Native is a different runtime and deserves a specialist who works in it daily.
Yes. Module federation, single-spa, and the question of whether micro-frontends are the right answer at all — usually they aren't — are part of the audit when your architecture makes them relevant. I flag the organizational cost alongside the technical one.
Common, and not a problem to audit. The migration plan will cover React 16 to 18 or 19 in phased steps, with the riskiest changes isolated per phase. Execution typically takes 2 to 6 weeks depending on codebase size and how many class components are in the mix.
Yes. Lighthouse, WebPageTest, and bundle analyzer comparisons against two or three competitor apps are included when performance is part of the audit scope. The benchmarks go into the report as reference baselines, not as headline numbers.