> ## Documentation Index
> Fetch the complete documentation index at: https://developer.zamp.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Sales Tax API Quickstart
> Go from an API key to your first sales tax calculation in four steps — authenticate, calculate tax on a transaction, and post it for filing.
This quickstart takes you from an API key to a filed-ready transaction in about five minutes. It's part of the [sales tax API documentation](/) and works the same whether you're using a trial key or a production key.
Need a key? Get a [free 30-day trial key](/guides/trial) — no credit card or sales call — or [copy your production key](/guides/production-api-access) from your Zamp account.
Use a [free trial key](/guides/trial) (preconfigured with all 47 remote-seller state registrations) to explore and test, or [production access](/guides/production-api-access) through your Zamp account when you're ready to go live.
Pass your API key as a bearer token in the `Authorization` header on every request. See [Authentication](/guides/authentication) for details.
```bash theme={null}
curl https://api.zamp.com/transactions \
-H "Authorization: Bearer {your-api-key}"
```
Send a transaction to [`POST /calculations`](/api-reference/calculations). The `shipToAddress` determines the taxing jurisdictions, and each line item's `productTaxCode` determines taxability — see [Tax codes](/guides/zamp-tax-codes) to find the right codes for your catalog.
```bash cURL theme={null}
curl -X POST https://api.zamp.com/calculations \
-H "Authorization: Bearer {your-api-key}" \
-H "Content-Type: application/json" \
-d '{
"id": "123",
"name": "INV-123",
"transactedAt": "2023-07-01T00:00:00.000Z",
"isResale": false,
"discount": 2,
"subtotal": 18,
"shippingHandling": 5,
"total": 23,
"shipToAddress": {
"line1": "120 SW 10TH AVE",
"line2": null,
"state": "KS",
"city": "TOPEKA",
"zip": "66612"
},
"lineItems": [
{
"id": "LI-123",
"amount": 10,
"quantity": 2,
"discount": 0,
"shippingHandling": 0,
"productName": "The Ultimate Sampler",
"productSku": "SAMPLER-100",
"productTaxCode": "R_TPP_FOOD-BEVERAGE_HOME-CONSUMPTION"
}
]
}'
```
```javascript Node.js theme={null}
const response = await fetch("https://api.zamp.com/calculations", {
method: "POST",
headers: {
"Authorization": "Bearer {your-api-key}",
"Content-Type": "application/json",
},
body: JSON.stringify({
id: "123",
name: "INV-123",
transactedAt: "2023-07-01T00:00:00.000Z",
isResale: false,
discount: 2,
subtotal: 18,
shippingHandling: 5,
total: 23,
shipToAddress: {
line1: "120 SW 10TH AVE",
line2: null,
state: "KS",
city: "TOPEKA",
zip: "66612",
},
lineItems: [
{
id: "LI-123",
amount: 10,
quantity: 2,
discount: 0,
shippingHandling: 0,
productName: "The Ultimate Sampler",
productSku: "SAMPLER-100",
productTaxCode: "R_TPP_FOOD-BEVERAGE_HOME-CONSUMPTION",
},
],
}),
});
const calculation = await response.json();
console.log(calculation.taxDue);
```
```python Python theme={null}
import requests
response = requests.post(
"https://api.zamp.com/calculations",
headers={"Authorization": "Bearer {your-api-key}"},
json={
"id": "123",
"name": "INV-123",
"transactedAt": "2023-07-01T00:00:00.000Z",
"isResale": False,
"discount": 2,
"subtotal": 18,
"shippingHandling": 5,
"total": 23,
"shipToAddress": {
"line1": "120 SW 10TH AVE",
"line2": None,
"state": "KS",
"city": "TOPEKA",
"zip": "66612",
},
"lineItems": [
{
"id": "LI-123",
"amount": 10,
"quantity": 2,
"discount": 0,
"shippingHandling": 0,
"productName": "The Ultimate Sampler",
"productSku": "SAMPLER-100",
"productTaxCode": "R_TPP_FOOD-BEVERAGE_HOME-CONSUMPTION",
},
],
},
)
print(response.json()["taxDue"])
```
The response returns the total `taxDue` plus one entry per taxing jurisdiction — state, county, and district — for each line item and for shipping. Abridged here; see the [Calculations reference](/api-reference/calculations) for the full response.
```json Response (abridged) theme={null}
{
"id": "123",
"name": "INV-123",
"taxDue": 1.58,
"taxes": [
{
"lineItemId": "LI-123",
"state": "KS",
"jurisdictionCode": "KS.S.20",
"jurisdictionName": "KANSAS",
"jurisdictionDivision": "STATE",
"taxableAmount": 18,
"taxRate": 0.04,
"taxDue": 0.72
},
{
"lineItemId": "LI-123",
"state": "KS",
"jurisdictionCode": "KS.C.177",
"jurisdictionName": "SHAWNEE COUNTY",
"jurisdictionDivision": "COUNTY",
"taxableAmount": 18,
"taxRate": 0.0135,
"taxDue": 0.243
}
]
}
```
Once the sale completes, persist it with [`POST /transactions`](/api-reference/transactions) using the same transaction shape. This is the core **calculate, then post** workflow behind every Zamp integration — calculations quote the tax, posted transactions become the returns Zamp files.
## Next steps
The recommended workflows for quoting tax and recording sales.
Every field on the object behind calculations and transactions.
Map your products to the right taxability rules.
Status codes and error formats you'll want to handle.
Before going live, review [Certifying your integration](/guides/certifying-your-integration) to make sure your build handles every customer scenario.