QR Code Generation

Generate QR codes for wallet addresses, ENS names, and payment links.

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Endpoints

Endpoint	Description	Price
GET /api/qr/:data	Basic QR code	FREE
GET /api/qr/address/:address	Wallet address QR	FREE
GET /api/qr/ens/:name	ENS name QR	$0.001
GET /api/qr/payment	EIP-681 payment QR	$0.001

---

GET /api/qr/:data

Generate a QR code for any text data.

Request

curl "https://api.web3identity.com/api/qr/Hello%20World" --output qr.png

Query Parameters

Param	Type	Default	Description
size	number	200	Image size in pixels (50-1000)
format	string	png	png, svg, or base64
color	string	000000	Foreground color (hex)
bg	string	ffffff	Background color (hex)
margin	number	4	Quiet zone margin

Response

Returns image binary (PNG/SVG) or JSON with base64:

# Get PNG (default)
curl "https://api.web3identity.com/api/qr/test" --output qr.png

# Get SVG
curl "https://api.web3identity.com/api/qr/test?format=svg" --output qr.svg

# Get base64 JSON
curl "https://api.web3identity.com/api/qr/test?format=base64"

Base64 Response:

{
  "data": "test",
  "format": "base64",
  "image": "data:image/png;base64,iVBORw0KGgo..."
}

---

GET /api/qr/address/:address

Generate a QR code for a wallet address with EIP-55 checksum.

Request

curl "https://api.web3identity.com/api/qr/address/0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045?size=300" \
  --output vitalik-qr.png

Response

PNG image containing the checksummed address.

SDK

const qrUrl = client.getAddressQRUrl('0xd8dA...');
// Returns: https://api.web3identity.com/api/qr/address/0xd8dA...

JavaScript

const BASE_URL = 'https://api.web3identity.com';

function getAddressQRUrl(address, size = 200) {
  return `${BASE_URL}/api/qr/address/${address}?size=${size}`;
}

// Use in HTML
const img = document.createElement('img');
img.src = getAddressQRUrl('0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', 300);
img.alt = 'Wallet QR Code';
document.body.appendChild(img);

React Component

function WalletQR({ address, size = 200 }) {
  const url = `https://api.web3identity.com/api/qr/address/${address}?size=${size}`;
  
  return (
    <img 
      src={url} 
      alt={`QR code for ${address.slice(0, 8)}...`}
      width={size}
      height={size}
    />
  );
}

// Usage
<WalletQR address="0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045" size={300} />

---

GET /api/qr/ens/:name

Generate a QR code for an ENS name with optional logo overlay.

Request

curl "https://api.web3identity.com/api/qr/ens/vitalik.eth?size=300&logo=true" \
  --output vitalik-ens-qr.png

Query Parameters

Param	Type	Default	Description
size	number	200	Image size
logo	boolean	false	Include ENS logo in center
resolve	boolean	true	Include resolved address

Response

QR code containing ethereum:vitalik.eth (EIP-681 format).

---

GET /api/qr/payment

Generate an EIP-681 payment request QR code.

Request

curl "https://api.web3identity.com/api/qr/payment?\
to=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&\
value=0.1&\
chainId=1" --output payment-qr.png

Query Parameters

Param	Type	Required	Description
to	string	Yes	Recipient address or ENS
value	string	No	ETH amount
token	string	No	Token contract address
amount	string	No	Token amount (if token specified)
chainId	number	No	Chain ID (default: 1)
data	string	No	Transaction data
size	number	No	Image size

Example: ETH Payment

# Request 0.1 ETH payment
curl "https://api.web3identity.com/api/qr/payment?\
to=vitalik.eth&\
value=0.1" --output eth-payment.png

Example: USDC Payment

# Request 100 USDC payment
curl "https://api.web3identity.com/api/qr/payment?\
to=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&\
token=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&\
amount=100&\
chainId=1" --output usdc-payment.png

EIP-681 Format

The QR code contains a standard payment URI:

ethereum:0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045@1?value=1e17

This is compatible with:

• MetaMask
• Rainbow
• Coinbase Wallet
• Most mobile wallets

---

Customization Examples

Branded QR (Dark Mode)

curl "https://api.web3identity.com/api/qr/address/0xd8dA...?\
color=8b5cf6&\
bg=1a1a2e&\
size=400" --output branded-qr.png

High Resolution for Print

curl "https://api.web3identity.com/api/qr/ens/yourname.eth?\
size=1000&\
margin=8&\
format=svg" --output print-qr.svg

Inline in HTML (base64)

async function getInlineQR(address) {
  const res = await fetch(
    `https://api.web3identity.com/api/qr/address/${address}?format=base64`
  );
  const { image } = await res.json();
  return image; // data:image/png;base64,...
}

// Use directly in img src
document.getElementById('qr').src = await getInlineQR('0xd8dA...');

---

Error Handling

Code	HTTP	Description
INVALID_ADDRESS	400	Malformed Ethereum address
INVALID_ENS	400	Invalid ENS name format
ENS_NOT_FOUND	404	ENS name not registered
SIZE_TOO_LARGE	400	Size exceeds 1000px

Error Response

{
  "error": true,
  "code": "INVALID_ADDRESS",
  "message": "Invalid Ethereum address format"
}

---

Related Endpoints

• ENS Resolution — Resolve names to addresses
• Health & Utilities — Other utility endpoints
• Wallet Balances — Check wallet holdings

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