Frontend React Components & Hooks

When this skill applies

Use this skill when building VTEX IO frontend apps using the react builder — creating React components that integrate with Store Framework as theme blocks, configuring interfaces.json, setting up contentSchemas.json for Site Editor, and applying styling patterns.

Creating custom storefront components (product displays, forms, banners)
Building admin panel interfaces with VTEX Styleguide
Registering components as Store Framework blocks
Exposing component props in Site Editor via contentSchemas.json
Applying css-handles for safe storefront styling

Do not use this skill for:

Backend service implementation (use vtex-io-service-apps instead)
GraphQL schema and resolver development (use vtex-io-graphql-api instead)
Manifest and builder configuration (use vtex-io-app-structure instead)

Decision rules

Every visible storefront element is a block. Blocks are declared in theme JSON and map to React components via interfaces.
interfaces.json (in /store) maps block names to React component files: "component" is the file name in /react (without extension), "allowed" lists child blocks, "composition" controls how children work ("children" or "blocks").
Each exported component MUST have a root-level file in /react that re-exports it. The builder resolves "component": "ProductReviews" to react/ProductReviews.tsx.
For storefront components, use vtex.css-handles for styling (not inline styles, not global CSS).
For admin components, use vtex.styleguide — the official VTEX Admin component library. No third-party UI libraries.
Use contentSchemas.json in /store to make component props editable in Site Editor (JSON Schema format).
Use react-intl and the messages builder for i18n — never hardcode user-facing strings.
Fetch data via GraphQL queries (useQuery from react-apollo), never via direct API calls from the browser.

Architecture:

Store Theme (JSON blocks)
  └── declares "product-reviews" block with props
        │
        ▼
interfaces.json → maps "product-reviews" to "ProductReviews" component
        │
        ▼
react/ProductReviews.tsx → React component renders
        │
        ├── useCssHandles() → CSS classes for styling
        ├── useQuery() → GraphQL data fetching
        └── useProduct() / useOrderForm() → Store Framework context hooks

Hard constraints

Constraint: Declare Interfaces for All Storefront Blocks

Every React component that should be usable as a Store Framework block MUST have a corresponding entry in store/interfaces.json. Without the interface declaration, the block cannot be referenced in theme JSON files.

Why this matters

The store builder resolves block names to React components through interfaces.json. If a component has no interface, it is invisible to Store Framework and will not render on the storefront.

Detection

If a React component in /react is intended for storefront use but has no matching entry in store/interfaces.json, warn the developer. The component will compile but never render.

Correct

{
  "product-reviews": {
    "component": "ProductReviews",
    "composition": "children",
    "allowed": ["product-review-item"]
  },
  "product-review-item": {
    "component": "ReviewItem"
  }
}

// react/ProductReviews.tsx
import ProductReviews from './components/ProductReviews'

export default ProductReviews

Wrong

// react/ProductReviews.tsx exists but NO store/interfaces.json entry
// The component compiles fine but cannot be used in any theme.
// Adding <product-reviews /> in a theme JSON will produce:
// "Block 'product-reviews' not found"
import ProductReviews from './components/ProductReviews'

export default ProductReviews

Constraint: Use VTEX Styleguide for Admin UIs

Admin panel components (apps using the admin builder) MUST use VTEX Styleguide (vtex.styleguide) for UI elements. You MUST NOT use third-party UI libraries like Material UI, Chakra UI, or Ant Design in admin apps.

Why this matters

VTEX Admin has a consistent design language enforced by Styleguide. Third-party UI libraries produce inconsistent visuals, may conflict with the Admin's global CSS, and add unnecessary bundle size. Apps submitted to the VTEX App Store with non-Styleguide admin UIs will fail review.

Detection

If you see imports from @material-ui, @chakra-ui/react, @chakra-ui, antd, or @ant-design in an admin app, warn the developer to use vtex.styleguide instead.

Correct

// react/admin/ReviewModeration.tsx
import React, { useState } from 'react'
import {
  Layout,
  PageHeader,
  Table,
  Button,
  Tag,
  Modal,
  Input,
} from 'vtex.styleguide'

interface Review {
  id: string
  author: string
  rating: number
  text: string
  status: 'pending' | 'approved' | 'rejected'
}

function ReviewModeration() {
  const [reviews, setReviews] = useState<Review[]>([])
  const [modalOpen, setModalOpen] = useState(false)

  const tableSchema = {
    properties: {
      author: { title: 'Author', width: 200 },
      rating: { title: 'Rating', width: 100 },
      text: { title: 'Review Text' },
      status: {
        title: 'Status',
        width: 150,
        cellRenderer: ({ cellData }: { cellData: string }) => (
          <Tag type={cellData === 'approved' ? 'success' : 'error'}>
            {cellData}
          </Tag>
        ),
      },
    },
  }

  return (
    <Layout fullWidth pageHeader={<PageHeader title="Review Moderation" />}>
      <Table
        items={reviews}
        schema={tableSchema}
        density="medium"
      />
    </Layout>
  )
}

export default ReviewModeration

Wrong

// react/admin/ReviewModeration.tsx
import React from 'react'
import { DataGrid } from '@material-ui/data-grid'
import { Button } from '@material-ui/core'

// Material UI components will look inconsistent in the VTEX Admin,
// conflict with global styles, and inflate bundle size.
// This app will fail VTEX App Store review.
function ReviewModeration() {
  return (
    <div>
      <DataGrid rows={[]} columns={[]} />
      <Button variant="contained" color="primary">Approve</Button>
    </div>
  )
}

Constraint: Export Components from react/ Root Level

Every Store Framework block component MUST have a root-level export file in the /react directory that matches the component value in interfaces.json. The actual implementation can live in subdirectories, but the root file must exist.

Why this matters

The react builder resolves components by looking for files at the root of /react. If interfaces.json declares "component": "ProductReviews", the builder looks for react/ProductReviews.tsx. Without this root export file, the component will not be found and the block will fail to render.

Detection

If interfaces.json references a component name that does not have a matching file at the root of /react, STOP and create the export file.

Correct

// react/ProductReviews.tsx — root-level export file
import ProductReviews from './components/ProductReviews/index'

export default ProductReviews

// react/components/ProductReviews/index.tsx — actual implementation
import React from 'react'
import { useCssHandles } from 'vtex.css-handles'

const CSS_HANDLES = ['container', 'title', 'list'] as const

interface Props {
  title: string
  maxReviews: number
}

function ProductReviews({ title, maxReviews }: Props) {
  const handles = useCssHandles(CSS_HANDLES)
  return (
    <div className={handles.container}>
      <h2 className={handles.title}>{title}</h2>
      {/* ... */}
    </div>
  )
}

export default ProductReviews

Wrong

react/components/ProductReviews/index.tsx exists but
react/ProductReviews.tsx does NOT exist.
The builder cannot find the component.
Error: "Could not find component ProductReviews"

Preferred pattern

Create the React component inside a subdirectory:

// react/components/ProductReviews/index.tsx
import React, { useMemo } from 'react'
import { useQuery } from 'react-apollo'
import { useProduct } from 'vtex.product-context'
import { useCssHandles } from 'vtex.css-handles'

import GET_REVIEWS from '../../graphql/getReviews.graphql'
import ReviewItem from './ReviewItem'

const CSS_HANDLES = [
  'reviewsContainer',
  'reviewsTitle',
  'reviewsList',
  'averageRating',
  'emptyState',
] as const

interface Props {
  title?: string
  showAverage?: boolean
  maxReviews?: number
}

function ProductReviews({
  title = 'Customer Reviews',
  showAverage = true,
  maxReviews = 10,
}: Props) {
  const handles = useCssHandles(CSS_HANDLES)
  const productContext = useProduct()
  const productId = productContext?.product?.productId

  const { data, loading, error } = useQuery(GET_REVIEWS, {
    variables: { productId, limit: maxReviews },
    skip: !productId,
  })

  const averageRating = useMemo(() => {
    if (!data?.reviews?.length) return 0

    const sum = data.reviews.reduce(
      (acc: number, review: { rating: number }) => acc + review.rating,
      0
    )

    return (sum / data.reviews.length).toFixed(1)
  }, [data])

  if (loading) return <div className={handles.reviewsContainer}>Loading...</div>
  if (error) return null

  return (
    <div className={handles.reviewsContainer}>
      <h2 className={handles.reviewsTitle}>{title}</h2>

      {showAverage && data?.reviews?.length > 0 && (
        <div className={handles.averageRating}>
          Average: {averageRating} / 5
        </div>
      )}

      {data?.reviews?.length === 0 ? (
        <p className={handles.emptyState}>No reviews yet.</p>
      ) : (
        <ul className={handles.reviewsList}>
          {data.reviews.map((review: { id: string; author: string; rating: number; text: string }) => (
            <ReviewItem key={review.id} review={review} />
          ))}
        </ul>
      )}
    </div>
  )
}

export default ProductReviews

Root export file:

// react/ProductReviews.tsx
import ProductReviews from './components/ProductReviews'

export default ProductReviews

Block interface:

{
  "product-reviews": {
    "component": "ProductReviews",
    "composition": "children",
    "allowed": ["product-review-form"],
    "render": "client"
  }
}

Site Editor schema:

{
  "definitions": {
    "ProductReviews": {
      "type": "object",
      "properties": {
        "title": {
          "type": "string",
          "title": "Section Title",
          "description": "Title displayed above the reviews list",
          "default": "Customer Reviews"
        },
        "showAverage": {
          "type": "boolean",
          "title": "Show average rating",
          "default": true
        },
        "maxReviews": {
          "type": "number",
          "title": "Maximum reviews",
          "default": 10,
          "enum": [5, 10, 20, 50]
        }
      }
    }
  }
}

Using the component in a Store Framework theme:

{
  "store.product": {
    "children": [
      "product-images",
      "product-name",
      "product-price",
      "buy-button",
      "product-reviews"
    ]
  },
  "product-reviews": {
    "props": {
      "title": "What Our Customers Say",
      "showAverage": true,
      "maxReviews": 20
    }
  }
}

Common failure modes

Importing third-party UI libraries for admin apps: Using @material-ui/core, @chakra-ui/react, or antd conflicts with VTEX Admin's global CSS, produces inconsistent visuals, and will fail App Store review. Use vtex.styleguide instead.
Directly calling APIs from React components: Using fetch() or axios exposes authentication tokens to the client and bypasses CORS restrictions. Use GraphQL queries that resolve server-side via useQuery from react-apollo.
Hardcoded strings without i18n: Components with hardcoded strings only work in one language. Use the messages builder and react-intl for internationalization.
Missing root-level export file: If interfaces.json references "component": "ProductReviews" but react/ProductReviews.tsx doesn't exist, the block silently fails to render.

Review checklist

Does every storefront block have a matching entry in store/interfaces.json?
Does every interfaces.json component have a root-level export file in /react?
Are admin apps using vtex.styleguide (no third-party UI libraries)?
Are storefront components using css-handles for styling?
Is data fetched via GraphQL (useQuery), not direct API calls?
Are user-facing strings using react-intl and the messages builder?
Is contentSchemas.json defined for Site Editor-editable props?

Reference

Developing Custom Storefront Components — Guide for building Store Framework components
Interfaces — How interfaces map blocks to React components
React Builder — React builder configuration and directory structure
Making a Custom Component Available in Site Editor — contentSchemas.json and Site Editor integration
Store Framework — Overview of the block-based storefront system
Using Components — How to use native and custom components in themes
VTEX Styleguide — Official component library for VTEX Admin UIs

vtex-io-react-apps

Frontend React Components & Hooks

When this skill applies

Decision rules

Hard constraints

Constraint: Declare Interfaces for All Storefront Blocks

Constraint: Use VTEX Styleguide for Admin UIs

Constraint: Export Components from react/ Root Level

Preferred pattern

Common failure modes

Review checklist

Reference