Displaying a User's NFT Collection on a Website

The user wants to show their NFTs on a website, but direct blockchain reads are slow and painful. ERC-721 doesn't have a tokensOfOwner method; you have to iterate over events or rely on ERC721Enumerable, which not every contract implements. We use specialized NFT APIs that index events and return ready-made lists. For example, for the BAYC collection, you get all tokens for an owner address in one request, without iterating millions of events. But there are pitfalls: IPFS gateways, slow loading, error handling. Our implementation accounts for all of this.

Why Not Read NFTs Directly from the Contract?

ERC-721 contracts store ownerOf(tokenId) and tokenURI(tokenId), but don't provide a reverse mapping. Without ERC721Enumerable, finding all tokens of a user via RPC means iterating all Transfer events in history or maintaining your own database. NFT APIs (Alchemy, Moralis, OpenSea) do the indexing for us — faster and more reliable. The alternative approach with a custom indexer requires infrastructure and development time, which is unjustified for most projects.

How to Fetch NFTs via Alchemy API

We use alchemy.nft.getNftsForOwner with SDK configuration.

// lib/nft.ts
import { Alchemy, Network, OwnedNft } from 'alchemy-sdk';

const alchemy = new Alchemy({
  apiKey: process.env.ALCHEMY_API_KEY,
  network: Network.ETH_MAINNET,
});

export interface NftItem {
  tokenId: string;
  contractAddress: string;
  name: string;
  description: string;
  imageUrl: string;
  collectionName: string;
  attributes: Array<{ trait_type: string; value: string | number }>;
}

export async function getWalletNfts(
  ownerAddress: string,
  opts?: { contractAddresses?: string[]; pageSize?: number },
): Promise<NftItem[]> {
  const response = await alchemy.nft.getNftsForOwner(ownerAddress, {
    contractAddresses: opts?.contractAddresses,
    pageSize: opts?.pageSize ?? 100,
    omitMetadata: false,
  });

  return response.ownedNfts.map(mapNft);
}

function mapNft(nft: OwnedNft): NftItem {
  const imageUrl = resolveIpfsUrl(
    nft.image?.cachedUrl ?? nft.image?.originalUrl ?? '',
  );

  return {
    tokenId: nft.tokenId,
    contractAddress: nft.contract.address,
    name: nft.name ?? `#${nft.tokenId}`,
    description: nft.description ?? '',
    imageUrl,
    collectionName: nft.contract.name ?? 'Unknown Collection',
    attributes: (nft.raw?.metadata?.attributes ?? []) as NftItem['attributes'],
  };
}

function resolveIpfsUrl(url: string): string {
  if (url.startsWith('ipfs://')) {
    return url.replace('ipfs://', 'https://cloudflare-ipfs.com/ipfs/');
  }
  return url;
}

{
  "ownedNfts": [
    {
      "contract": { "address": "0x..." },
      "tokenId": "1",
      "tokenType": "ERC721",
      "title": "My NFT",
      "description": "...",
      "metadata": { "image": "ipfs://..." }
    }
  ],
  "pageKey": "...",
  "totalCount": 42
}

Alchemy NFT API Documentation

For real-time updates, WebSocket notifications about new tokens can be connected, which is useful for dynamic collections.

Gallery and Card Components

Gallery Component

We use React Query for fetching and caching data.

// components/NftGallery.tsx
import { useQuery } from '@tanstack/react-query';
import { getWalletNfts, NftItem } from '@/lib/nft';

interface NftGalleryProps {
  address: string;
  contractFilter?: string[];
}

export function NftGallery({ address, contractFilter }: NftGalleryProps) {
  const { data, isLoading, error } = useQuery({
    queryKey: ['nfts', address, contractFilter],
    queryFn: () => getWalletNfts(address, { contractAddresses: contractFilter }),
    staleTime: 60_000, // NFTs change rarely — cache for a minute
    enabled: !!address,
  });

  if (isLoading) return <NftGridSkeleton count={12} />;
  if (error) return <ErrorState message="Не удалось загрузить NFT" />;
  if (!data?.length) return <EmptyState />;

  return (
    <div className="grid grid-cols-2 gap-4 sm:grid-cols-3 lg:grid-cols-4">
      {data.map(nft => (
        <NftCard key={`${nft.contractAddress}-${nft.tokenId}`} nft={nft} />
      ))}
    </div>
  );
}

Card and Detail View

// components/NftCard.tsx
import { useState } from 'react';
import { NftItem } from '@/lib/nft';

export function NftCard({ nft }: { nft: NftItem }) {
  const [imgError, setImgError] = useState(false);

  return (
    <div className="group relative overflow-hidden rounded-xl border border-white/10 bg-neutral-900">
      <div className="aspect-square overflow-hidden bg-neutral-800">
        {imgError ? (
          <div className="flex h-full items-center justify-center text-neutral-500">
            <ImageIcon className="h-12 w-12" />
          </div>
        ) : (
          <img
            src={nft.imageUrl}
            alt={nft.name}
            loading="lazy"
            decoding="async"
            className="h-full w-full object-cover transition-transform group-hover:scale-105"
            onError={() => setImgError(true)}
          />
        )}
      </div>
      <div className="p-3">
        <p className="truncate text-xs text-neutral-400">{nft.collectionName}</p>
        <p className="mt-0.5 truncate font-medium text-white">{nft.name}</p>
      </div>
    </div>
  );
}

// components/NftDetail.tsx
export function NftDetail({ nft }: { nft: NftItem }) {
  return (
    <div className="space-y-6">
      <img src={nft.imageUrl} alt={nft.name} className="w-full rounded-2xl" />
      <div>
        <h2 className="text-2xl font-bold">{nft.name}</h2>
        <p className="mt-1 text-sm text-neutral-400">
          {nft.collectionName} · #{nft.tokenId}
        </p>
      </div>
      {nft.description && (
        <p className="text-sm leading-relaxed text-neutral-300">{nft.description}</p>
      )}
      {nft.attributes.length > 0 && (
        <div>
          <h3 className="mb-3 text-sm font-semibold uppercase tracking-wider text-neutral-500">
            Attributes
          </h3>
          <div className="grid grid-cols-3 gap-2">
            {nft.attributes.map((attr, i) => (
              <div key={i} className="rounded-lg border border-blue-500/20 bg-blue-500/5 p-2 text-center">
                <p className="text-xs text-blue-400">{attr.trait_type}</p>
                <p className="mt-0.5 text-sm font-medium">{attr.value}</p>
              </div>
            ))}
          </div>
        </div>
      )}
    </div>
  );
}

Such a structure allows easy embedding of components into any React project.

ERC-1155 Support and Pagination

For ERC-1155 tokens, Alchemy returns balance. We check tokenType and add a quantity field. For large collections we implement pagination via pageKey.

// utils/nft-extras.ts
export function filterErc1155WithBalance(
  nfts: OwnedNft[],
  mapNft: (nft: OwnedNft) => NftItem,
) {
  return nfts
    .filter(nft => nft.tokenType === 'ERC1155')
    .map(nft => ({
      ...mapNft(nft),
      quantity: nft.balance,
    }));
}

export async function getAllWalletNfts(
  ownerAddress: string,
): Promise<NftItem[]> {
  const all: NftItem[] = [];
  let pageKey: string | undefined;

  do {
    const response = await alchemy.nft.getNftsForOwner(ownerAddress, {
      pageKey,
      pageSize: 100,
    });
    all.push(...response.ownedNfts.map(mapNft));
    pageKey = response.pageKey;
  } while (pageKey);

  return all;
}

Comparison of Solutions

NFT API Comparison

RPC vs NFT API

Work Stages

1. Analysis — determine which networks and contracts are needed, agree on API.
2. Integration — connect SDK, implement fetching and display.
3. Optimization — lazy loading, caching, error handling.
4. Testing — verify on real wallets with large collections.
5. Deployment — deploy to production, set up monitoring.

What's Included

• Documentation on integration and API key setup.
• Source code of React/TypeScript components.
• Deployment and update instructions.
• Test access to a working prototype.
• Support for 2 weeks after delivery.

Timelines and Cost

Basic gallery with Alchemy API, lazy loading, and detail view — 1–2 days. Extended version with collection filters, pagination, ERC-1155 support, and multichain — 3–4 days. Cost is calculated individually based on complexity and stack. For example, self-developed infrastructure and time can cost over $5,000; our solution is significantly cheaper. Contact us for a project estimate — we'll find the optimal solution.

Common Integration Mistakes

• Unhandled IPFS — images don't load without a gateway. Always replace ipfs:// with https://cloudflare-ipfs.com/ipfs/.
• Ignoring balance for ERC-1155 — can lead to incorrect display of quantity. Always check tokenType.
• Too short staleTime — NFTs change rarely; caching for 1–5 minutes significantly reduces API load.
• Missing fallback for images — show a placeholder on error, otherwise the user sees a broken icon.

For adding NFT search and filtering by collections, we integrate state on the frontend or use server-side search via the Alchemy API. This allows quick finding of desired tokens and sorting by collections.

We guarantee compatibility with leading collections and many years of experience integrating NFT APIs. We have been developing since 2018 and have implemented over 10 projects with NFT display for marketplaces and crypto portfolios. Get a consultation — order integration for your project. Using the Alchemy API can save up to $1,000 per month on servers and indexing.

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.