Calculate Tax Before Checkout

Bags calculates VAT, GST, and sales tax automatically using regional tax providers routed by customer country (EU VAT, UK VAT, India GST, US sales tax where nexus is active, and zero-tax elsewhere). Request a tax quote before creating a checkout session to show your customers a breakdown of subtotal, tax, and total.

How it works

Customer enters their billing address
You call the tax quote endpoint with the payment link ID and address
Bags returns the tax breakdown (subtotal, tax amount, total) and a signed quoteToken
You pass the quoteToken when creating the checkout session to lock in the tax amount

The quote token is cryptographically signed and ensures the tax amount cannot be tampered with between the quote and checkout steps.

Request a tax quote

const response = await fetch("https://www.getbags.app/api/tax/quote", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.BAG_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    paymentLinkId: "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    customerAddress: {
      address_line_1: "100 Main St",
      address_city: "San Francisco",
      address_province: "CA",
      address_postal_code: "94105",
      address_country: "US",
      address_type: "billing",
    },
  }),
});

const { data: quote } = await response.json();
console.log(`Subtotal: $${(quote.subtotalCents / 100).toFixed(2)}`);
console.log(`Tax:      $${(quote.taxCents / 100).toFixed(2)}`);
console.log(`Total:    $${(quote.totalCents / 100).toFixed(2)}`);

import os
import requests

API_KEY = os.environ["BAG_API_KEY"]
BASE_URL = "https://www.getbags.app"

response = requests.post(
    f"{BASE_URL}/api/tax/quote",
    headers={
        "Authorization": f"Bearer {API_KEY}",
        "Content-Type": "application/json",
    },
    json={
        "paymentLinkId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
        "customerAddress": {
            "address_line_1": "100 Main St",
            "address_city": "San Francisco",
            "address_province": "CA",
            "address_postal_code": "94105",
            "address_country": "US",
            "address_type": "billing",
        },
    },
)

data = response.json()["data"]
print(f"Subtotal: ${data['subtotalCents'] / 100:.2f}")
print(f"Tax:      ${data['taxCents'] / 100:.2f}")
print(f"Total:    ${data['totalCents'] / 100:.2f}")

curl -X POST https://www.getbags.app/api/tax/quote \
  -H "Authorization: Bearer $BAG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "paymentLinkId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "customerAddress": {
      "address_line_1": "100 Main St",
      "address_city": "San Francisco",
      "address_province": "CA",
      "address_postal_code": "94105",
      "address_country": "US",
      "address_type": "billing"
    }
  }'

Response

{
  "status": "success",
  "data": {
    "subtotalCents": 2999,
    "taxCents": 262,
    "totalCents": 3261,
    "calculationId": "calc_abc123",
    "quoteToken": "eyJhbGciOiJIUzI1NiIs..."
  }
}

Field	Type	Description
`subtotalCents`	`number`	Product price in cents before tax
`taxCents`	`number`	Calculated tax amount in cents
`totalCents`	`number`	Total amount including tax in cents
`calculationId`	`string`	Provider calculation reference (format varies by region)
`quoteToken`	`string`	Signed token to pass to checkout session creation

Using the quote in checkout

Pass the quoteToken and totals snapshot when creating a checkout session via POST /api/checkout/session:

const response = await fetch("https://www.getbags.app/api/checkout/session", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    linkId: "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    quoteToken: quote.quoteToken,
    walletAddress: "0xCustomerWallet",
    walletType: "evm",
    network: "base",
    customer: {
      name: "Jane Doe",
      email: "jane@example.com",
      address: "100 Main St, San Francisco, CA 94105",
      country: "US",
    },
    totalsSnapshot: {
      subtotalCents: quote.subtotalCents,
      taxCents: quote.taxCents,
      totalCents: quote.totalCents,
      calculationId: quote.calculationId,
    },
  }),
});

Address fields

Field	Type	Required	Description
`address_line_1`	`string`	Yes	Street address
`address_city`	`string`	Yes	City
`address_province`	`string`	Yes	State, province, or region code
`address_postal_code`	`string`	Yes	ZIP or postal code
`address_country`	`string`	Yes	ISO 3166-1 alpha-2 country code (e.g., `US`, `DE`, `GB`)
`address_type`	`string`	Yes	Must be `"billing"`

Tax calculation details

Bags routes quotes to the active provider for the customer's country:

Region	Provider (v0)
EU	Hardcoded EU VAT rates (per active country gate)
GB	UK VAT
IN	India GST
US	US sales tax (per active nexus state; $0 when no nexus)
Other	Zero tax

Tax is based on the customer's billing address and Bags' MoR registration. Coverage expands as new regions activate — do not assume every jurisdiction returns non-zero tax. See Tax Collection & Filing for remittance.

Calculate Tax Before Checkout

How it works

Request a tax quote

Response

Using the quote in checkout

Address fields

Tax calculation details

What's next

Build a Custom Checkout

Pricing & Tax

Tax Collection

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