Transactions and adjustments · POST

Create a transaction

Saves a completed sales tax calculation as a transaction with its original line items and tax amounts. Transactions cannot be edited; use an adjustment to record a refund or correction.

POST/v1/transactions

Parameters

Send these headers and path or query values with the request.

Name	Type	Required	Description
`Authorization`	`string`	Yes	Send your API key as a bearer token.
`Content-Type`	`string`	Yes	Use application/json.
`Idempotency-Key`	`string`	Yes	A caller-generated key. Reusing it with the same canonical request returns the original effect. Reusing it with different content returns a conflict.
`expand`	`string`	No	Set to audit for an authorized customer-safe audit expansion.

Request body

Required JSON body.

Name	Type	Required	Description
`calculation_id`	`string`	Yes	See the request example for the full field shape.
`reference`	`string`	Yes	See the request example for the full field shape.
`occurred_at`	`string`	No	See the request example for the full field shape.

Responses

201

The transaction record was saved.

Headers: Request-Id, Idempotent-Replayed

400

The request shape, parameter, or header is invalid.

401

A valid API key is required.

Headers: WWW-Authenticate

403

The authenticated key cannot perform this operation.

404

The resource does not exist in the authenticated workspace.

409

The request conflicts with an existing idempotency key or the current state of a saved record.

422

The request is valid, but the API cannot complete it. For example, the facts may not qualify or an adjustment may exceed the amounts left to reverse.

429

The request exceeded an API safety limit. It did not count toward API usage.

Headers: Retry-After

503

A required service is unavailable, so the API could not process the request.

Headers: Retry-After

Live request

Try this endpoint

api.salestaxcalculatorapi.com

The browser sends the request straight to the API. Your API key never passes through this website's server.

API keyexpand

Idempotency key

Request body · JSON

POST requests can create records and use your API quota. Check the request body before sending.

Request

Shell

curl --request POST \
  --url "https://api.salestaxcalculatorapi.com/v1/transactions" \
  --header "Authorization: Bearer $SALESTAX_API_KEY"
  --header "Content-Type: application/json" \
  --header "Idempotency-Key: order-1001-txn" \
  --data '{"calculation_id":"calc_01J6A3S8Z6K4M6T2Y2W9M5X8Q0","reference":"order-1001"}'

201 responseJSON

{
  "id": "txn_01J6A4DN7ZAVC0QJ2KP6NQYB8M",
  "object": "transaction",
  "reference": "order-1001",
  "calculation_id": "calc_01J6A3S8Z6K4M6T2Y2W9M5X8Q0",
  "currency": "CAD",
  "subtotal": "100.00",
  "taxable_amount": "100.00",
  "tax": "13.00",
  "total": "113.00",
  "adjusted_amount": "0.00",
  "adjusted_tax": "0.00",
  "request_id": "req_01J6A3RZ1HT2K3W2X8R7P1J4C9",
  "created_at": "2026-08-29T12:01:00Z"
}

400 errorapplication/problem+json

{
  "type": "https://api.salestaxcalculatorapi.com/problems/invalid_request",
  "title": "Invalid request",
  "status": 400,
  "detail": "The request body must be valid JSON.",
  "instance": "/v1/calculations",
  "code": "invalid_request",
  "request_id": "req_01J6A3RZ1HT2K3W2X8R7P1J4C9",
  "retryable": false
}

Parameters

Send these headers and path or query values with the request.

Name	Type	Required	Description
`Authorization`	`string`	Yes	Send your API key as a bearer token.
`Content-Type`	`string`	Yes	Use application/json.
`Idempotency-Key`	`string`	Yes	A caller-generated key. Reusing it with the same canonical request returns the original effect. Reusing it with different content returns a conflict.
`expand`	`string`	No	Set to audit for an authorized customer-safe audit expansion.

Name

Type

Required

Description

calculation_id

string

Yes

See the request example for the full field shape.

reference

string

Yes

See the request example for the full field shape.

occurred_at

string

See the request example for the full field shape.

Responses

201

The transaction record was saved.

Headers: Request-Id, Idempotent-Replayed

400

The request shape, parameter, or header is invalid.

401

A valid API key is required.

Headers: WWW-Authenticate

403

The authenticated key cannot perform this operation.

404

The resource does not exist in the authenticated workspace.

409

The request conflicts with an existing idempotency key or the current state of a saved record.

422

The request is valid, but the API cannot complete it. For example, the facts may not qualify or an adjustment may exceed the amounts left to reverse.

429

The request exceeded an API safety limit. It did not count toward API usage.

Headers: Retry-After

503

A required service is unavailable, so the API could not process the request.

Headers: Retry-After

curl --request POST \ --url "https://api.salestaxcalculatorapi.com/v1/transactions" \ --header "Authorization: Bearer $SALESTAX_API_KEY" --header "Content-Type: application/json" \ --header "Idempotency-Key: order-1001-txn" \ --data '{"calculation_id":"calc_01J6A3S8Z6K4M6T2Y2W9M5X8Q0","reference":"order-1001"}'

{ "id": "txn_01J6A4DN7ZAVC0QJ2KP6NQYB8M", "object": "transaction", "reference": "order-1001", "calculation_id": "calc_01J6A3S8Z6K4M6T2Y2W9M5X8Q0", "currency": "CAD", "subtotal": "100.00", "taxable_amount": "100.00", "tax": "13.00", "total": "113.00", "adjusted_amount": "0.00", "adjusted_tax": "0.00", "request_id": "req_01J6A3RZ1HT2K3W2X8R7P1J4C9", "created_at": "2026-08-29T12:01:00Z" }

{ "type": "https://api.salestaxcalculatorapi.com/problems/invalid_request", "title": "Invalid request", "status": 400, "detail": "The request body must be valid JSON.", "instance": "/v1/calculations", "code": "invalid_request", "request_id": "req_01J6A3RZ1HT2K3W2X8R7P1J4C9", "retryable": false }