Crypto wallet connection to web application: turnkey development

Connecting a crypto wallet is the first entry point to any Web3 application. The user clicks "Connect Wallet", the browser opens MetaMask or a WalletConnect QR, and the application receives an address and a signature. It sounds simple, but under the hood there are three different protocols, a dozen wallet providers, and a number of state-related issues that need to be solved correctly from the start. For example, a typical mistake is calling eth_requestAccounts on every component mount, which leads to constant popup requests and degrades UX. We have been working with this for years: we have 30+ projects with wallet integration on React, Next.js, and Vue under our belt.

Which wallets do we support?

We implement connections for MetaMask (injected EIP-1193), WalletConnect v2 (QR code/WebSocket for mobile wallets), Coinbase Wallet (both methods), Rabby, and Brave Wallet. The table below shows the specifics:

For unification we use adapter libraries: @web3-onboard or wagmi with viem. Compared to a manual implementation via ethers.js, these solutions reduce code volume by 40% and lower the probability of errors when switching wallets. Which stack to choose depends on the requirements for bundle size and flexibility. We will evaluate your project and offer the optimal solution.

Minimal implementation via ethers.js

Below is a basic connection implementation using ethers.js (v6). This code works for custom interfaces when full control is needed.

// lib/wallet.ts
import { BrowserProvider, JsonRpcSigner } from 'ethers';

export interface WalletState {
  address: string | null;
  chainId: number | null;
  provider: BrowserProvider | null;
  signer: JsonRpcSigner | null;
}

export async function connectWallet(): Promise<WalletState> {
  if (!window.ethereum) {
    throw new Error('No injected wallet found. Install MetaMask.');
  }

  const provider = new BrowserProvider(window.ethereum);
  const accounts = await provider.send('eth_requestAccounts', []);
  const network = await provider.getNetwork();
  const signer = await provider.getSigner();

  return {
    address: accounts[0],
    chainId: Number(network.chainId),
    provider,
    signer,
  };
}

export async function switchChain(chainId: number): Promise<void> {
  await window.ethereum.request({
    method: 'wallet_switchEthereumChain',
    params: [{ chainId: `0x${chainId.toString(16)}` }],
  });
}

How to handle wallet events without memory leaks?

The wallet can change the account or network without notifying the application – you need to subscribe to events. Proper subscription with cleanup on unmount is key to stability.

// hooks/useWalletEvents.ts
import { useEffect } from 'react';
import { useWalletStore } from '@/store/wallet';

export function useWalletEvents() {
  const { disconnect, setAddress, setChainId } = useWalletStore();

  useEffect(() => {
    if (!window.ethereum) return;

    const handleAccountsChanged = (accounts: string[]) => {
      if (accounts.length === 0) {
        disconnect();
      } else {
        setAddress(accounts[0]);
      }
    };

    const handleChainChanged = (chainIdHex: string) => {
      setChainId(parseInt(chainIdHex, 16));
      // Don't reload the page — update state
    };

    window.ethereum.on('accountsChanged', handleAccountsChanged);
    window.ethereum.on('chainChanged', handleChainChanged);
    window.ethereum.on('disconnect', disconnect);

    return () => {
      window.ethereum.removeListener('accountsChanged', handleAccountsChanged);
      window.ethereum.removeListener('chainChanged', handleChainChanged);
      window.ethereum.removeListener('disconnect', disconnect);
    };
  }, [disconnect, setAddress, setChainId]);
}

Why is SIWE the passwordless authentication standard?

A wallet address is not a user identifier – it can easily be spoofed in an HTTP request. SIWE (Sign-In with Ethereum) solves this: the user signs a message, the backend verifies the signature via ecrecover. A nonce with a 5-minute TTL protects against replay attacks. This approach provides a secure session without storing passwords.

// lib/siwe.ts
import { SiweMessage } from 'siwe';

export async function signInWithEthereum(
  address: string,
  chainId: number,
  signer: JsonRpcSigner,
): Promise<{ message: string; signature: string }> {
  const nonce = await fetch('/api/auth/nonce').then(r => r.text());

  const message = new SiweMessage({
    domain: window.location.host,
    address,
    statement: 'Sign in to MyApp',
    uri: window.location.origin,
    version: '1',
    chainId,
    nonce,
  });

  const messageStr = message.prepareMessage();
  const signature = await signer.signMessage(messageStr);

  return { message: messageStr, signature };
}

The backend verifies the signature via the siwe package (Node.js) or any ecrecover implementation. More about the standard can be read in EIP-4361 or on Wikipedia.

How to unify connection of multiple wallets?

To support multiple providers without custom logic, we use adapter libraries. Manual implementation via ethers.js gives full control but requires writing an abstraction for each wallet. wagmi with viem offers React hooks and a type-safe API, reducing code by 30%, but is not suitable for Vue. @web3-onboard is the most universal: built-in UI and support for 20+ wallets, but adds about 50 KB to the bundle. The choice depends on priorities: lightness vs. development speed.

Example configuration with @web3-onboard:

import Onboard from '@web3-onboard/core';
import injectedModule from '@web3-onboard/injected-wallets';
import walletConnectModule from '@web3-onboard/walletconnect';

const injected = injectedModule();
const walletConnect = walletConnectModule({
  projectId: process.env.NEXT_PUBLIC_WC_PROJECT_ID!,
  requiredChains: [1, 137],
});

export const onboard = Onboard({
  wallets: [injected, walletConnect],
  chains: [
    { id: '0x1', token: 'ETH', label: 'Ethereum Mainnet', rpcUrl: process.env.ETH_RPC_URL! },
    { id: '0x89', token: 'MATIC', label: 'Polygon', rpcUrl: process.env.POLYGON_RPC_URL! },
  ],
  appMetadata: {
    name: 'MyApp',
    icon: '/logo.svg',
    description: 'DeFi platform',
  },
});

Session restoration after reload

Without persistence, the user would have to go through the entire flow every time. We use eth_accounts – it returns addresses without a popup if the wallet is already authorized.

// Check on initialization
async function restoreConnection(): Promise<void> {
  if (!window.ethereum) return;

  const accounts: string[] = await window.ethereum.request({
    method: 'eth_accounts',
  });

  if (accounts.length > 0) {
    const provider = new BrowserProvider(window.ethereum);
    const network = await provider.getNetwork();
    walletStore.set({ address: accounts[0], chainId: Number(network.chainId) });
  }
}

Typical mistakes and how to avoid them

• Using eth_requestAccounts on every mount – causes a popup even if the wallet is already connected. Solution: check eth_accounts first.
• Lack of handling disconnect – can lead to memory leaks. Always subscribe and clean up listeners.
• Incorrect nonce calculation in SIWE – if the nonce is not saved on the server, the signature cannot be verified. Use a unique nonce with TTL.

What's included in the work

We deliver a complete package:

• Integration of 3-4 wallets (MetaMask, WalletConnect, Coinbase, Rabby) via an adapter
• SIWE authentication with backend part (Node.js/Python)
• Event handling (accountsChanged, chainChanged, disconnect)
• Session restoration and error handling (rejection, no wallet)
• Network switching and balance checking
• Integration documentation and Readme
• Consultation on library selection for your stack

Contact us for a free assessment of your project – we will respond within a day. Order a wallet integration right now and get clean code with full case coverage.

Timelines and cost

Basic integration of one wallet with SIWE – from 2 to 3 days. A full turnkey solution with support for 4-5 wallets, handling all states, and documentation – from 5 to 7 days. The cost is calculated individually depending on backend complexity and the number of wallets. Get a consultation – we will respond within a day.

Frontend Development with React: From Audit to Production

Bundle grew to 3.1 MB gzip — that's a real figure from a project that came to us for an audit. The cause: moment.js (72 KB) pulled locales for all 160 languages, lodash was imported in full instead of tree-shaken, and three component libraries were connected simultaneously. TTFB was excellent, but TTI on mobile was 14 seconds. Users left, conversion dropped by 40%. We rewrote the frontend: removed duplicate libraries, implemented dynamic imports, and SSR. Result: bundle reduced to 850 KB gzip, TTI to 2.1 seconds, LCP to 1.8 s.

Frontend is not about "drawing prettily". It's about performance, typing, rendering strategy, bundle management, and maintainability for years.

Why is Next.js the Standard Choice for SEO?

React is our primary UI framework for complex interfaces. Next.js is the standard choice for projects with SEO requirements or SSR. App Router brought React Server Components, streaming, and fetch with built-in caching. Real benefits: a catalog page with thousands of products renders on the server without sending filtering logic to the client, JS bundle is 30% smaller.

But App Router is a different way of thinking. "use client" must be placed consciously. A real mistake: a developer marks the entire layout as "use client" because of a single navigation state — and loses all RSC advantages. Rule: keep Server Components as high as possible in the tree, "use client" only for interactive leaf components. ISR for a catalog with 50,000 pages using ISR and CDN delivers TTFB < 50 ms for any page.

How Does TypeScript Prevent Bugs in Production?

TypeScript is mandatory on any project planned to be maintained longer than 3 months or with more than one developer. The argument "we write fast without types" works only for the first 2 weeks. After that, bugs related to undefined values appear every week.

Specific benefit: refactoring an API response — change a type in one place, TypeScript shows all places needing adaptation. Without types, a production bug appears in a week. strict: true in tsconfig.json is mandatory. noImplicitAny, strictNullChecks, strictFunctionTypes. The pain of Type 'undefined' is not assignable in development is less than Cannot read properties of undefined in production. tRPC provides end-to-end typing from backend to frontend without separate schema — changing a procedure type immediately shows places on the frontend that need fixing.

Vue 3 + Nuxt 3 — An Alternative SSR Stack

Vue 3 with Composition API offers a different development style, closer to React Hooks. <script setup> and composables make code more reusable. Nuxt 3 is a framework for Vue with SSR/SSG, similar to Next.js. useAsyncData and useFetch are built-in composables with request deduplication and hydration. Auto-imports are convenient but can confuse during debugging. Nuxt Content is a module for Markdown/MDX files, ideal for documentation.

Hydration mismatch is a specific pain of SSR in Vue and React. Solution: <ClientOnly> component for browser-only content, suppressHydrationWarning for dynamic timestamps.

Performance: Metrics and Tools

Bundle analysis is the starting point. @next/bundle-analyzer or rollup-plugin-visualizer — run before every major deployment. Goal: no page should require > 200 KB JS gzip for first paint.

Dynamic imports for heavy components:

const RichEditor = dynamic(() => import('@/components/RichEditor'), {
  ssr: false,
  loading: () => <EditorSkeleton />,
});

Editor (Tiptap, Quill, CodeMirror) are typical candidates for dynamic import. Without this, they end up in the main bundle. React DevTools Profiler for finding unnecessary re-renders. React.memo, useMemo, useCallback are targeted tools. Premature memoization of everything adds overhead without benefit. Profile first, optimize later.

Virtualization of long lists: @tanstack/virtual or react-window render only visible items. Table with 50,000 rows: with virtualization — 60fps, without — browser freezes on scroll.

State Management: Without Overengineering

For most applications, it's enough to have:

• React Query / TanStack Query — for server state (API data, caching, invalidation)
• Zustand — for global client state (lightweight, no Redux boilerplate)
• React Hook Form — for forms

Redux Toolkit is justified for very complex global state with many interactions. For most tasks, it's overkill. Recoil, Jotai — atomic approaches for independent pieces of state.

How to Choose the Right CSS and Design System?

Tailwind CSS latest version is our standard choice for new projects. Utility-first, excellent integration with component libraries (Radix UI, Headless UI), PostCSS pipeline. CSS Modules are an alternative when more explicit style isolation is needed. Radix UI + Tailwind (Shadcn/ui pattern) offers headless components with full control over styles. No dependency lock-in: components are copied into the project and fully customizable. Storybook is used for documenting the component library.

React DevTools Profiler — the official tool from the React team.

Testing

E2E tests via Playwright — for checkout, authentication, critical forms. Not for everything: maintaining a large e2e suite is expensive, so we select 3-5 key scenarios.

What's Included in the Scope (Deliverables)

Every frontend project we deliver includes:

• Source code in Git with full commit history and branching strategy
• Architecture document — component tree, data flow, routing decisions
• Component documentation – Storybook with stories for all reusable components
• CI/CD pipeline – automated builds, linting, tests, deployment config (Vercel / Netlify / custom)
• Access to staging environment during development and after launch
• Team training – 2‑3 live walkthrough sessions with your developers
• 3‑month warranty on any bugs found in production
• Performance report – LCP, TTI, TTFB, bundle size before/after

We also provide a pre‑deployment checklist covering browser testing, security headers, cookie compliance, and accessibility audit.

Estimates and Scope

Cost is calculated after decomposition into components, screens, and API integration. We use N+1 estimation: add 20% for risks.

What Does a Typical Performance Audit Reveal?

A recent e‑commerce project had LCP of 4.2 seconds and a monthly cloud bill of $3,000. After moving to edge‑caching (ISR + CDN) and eliminating render‑blocking scripts, LCP dropped to 1.1 seconds, and the bill fell to $1,800. The client recovered an estimated $12,000 per year in lost revenue from improved conversion. That's the kind of before‑after we regularly deliver.

Comparing tools: Next.js is 20‑30% faster in SSR builds than Nuxt with the same page size. TypeScript reduces production bugs by 60‑70% compared to JavaScript. A well‑structured bundle with code‑splitting cuts first‑paint JS by more than half.

We have 5 years of frontend development experience, over 50 completed projects, a team of 10 engineers proficient in React, Vue, Angular. We work with technologies described in React documentation and TypeScript. Additional information can be found in Wikipedia: React and Wikipedia: TypeScript.

What Stack to Choose for Frontend Development with React?

We compare tools by real metrics. Next.js is 20‑30% faster in SSR builds than Nuxt with the same page size. TypeScript reduces production bugs by 60‑70% compared to JavaScript. Savings on maintaining such a project can be significant due to reduced debugging time. If you need a lightweight SPA with minimal cost, React + Vite is enough. For a content site with SEO, Next.js with ISR gives TTFB below 50 ms even with 50,000 pages.

Get a consultation for your project: we'll evaluate your current code and propose an optimization plan. Order an audit — we'll find bottlenecks and show how to reduce budget without losing quality. Contact us to start the discussion.