# business.register_sales_tax

Record an evidenced sales-tax registration and create its standard tax codes. Requires an interactive owner; does not register with an authority or file a return.

## What it does

Record the business's sales-tax registration — Singapore GST, Canadian GST/HST (with the registrant's province) or the separate QST/PST/RST, or UK VAT — from its effective date, evidenced by the registration certificate as source_document_id, and seed that regime's standard tax codes (output, input, reverse-charge/imported-services and non-recoverable, at the current official rates). Preview what a regime seeds with the business read's sales_tax_regimes action. Owner-only and interactive. Files no return.

## Before you send it

Requires an interactive OAuth connection; headless credentials are refused. Effective membership, application grant and token permissions still apply. Describe `business.register_sales_tax` through `GET /v1/catalog/commands/{name}` before acting.

The envelope may reference a registered source document of kind `source_document`; this is separate from any evidence required by the input.

## Inputs

Put these fields inside the envelope's `input` object. The outer envelope names the command, a stable `idempotency_key` and `effective_at`; [request and recovery rules](/docs/api/) explain those separately. Use exact minor-unit integer strings for monetary fields. Take existing IDs from prior reads or command results; choose a new identity only where the command asks for one.

Required means required within its containing object; an optional parent can be omitted.

| Field | Type | Required | Meaning and accepted values |
|---|---|---|---|
| `regime` | string | Yes | sg_gst (Singapore GST); ca_gst_hst (Canadian GST/HST), ca_qst (Quebec QST), ca_pst_bc, ca_pst_sk, ca_rst_mb (provincial sales taxes, kept apart from GST/HST); gb_vat (UK VAT). It must be a regime of the country the business is incorporated in. There is no US regime: record US state sales tax as custom codes with tax_codes.create. Choose `"sg_gst"`, `"ca_gst_hst"`, `"ca_qst"`, `"ca_pst_bc"`, `"ca_pst_sk"`, `"ca_rst_mb"`, `"gb_vat"`. Example: `"gb_vat"`. |
| `registrationNumber` | string | Yes | As issued: a Singapore UEN or IRAS GST number (201912345K, M2-1234567-K); a Canadian BN with its RT account (123456789RT0001); a QST number (1234567890TQ0001); PST-1234-5678 (BC); a UK VAT number (GB123456789). Spaces are ignored. Minimum length: `1`. Example: `"GB123456789"`. |
| `province` | string | No | Required for ca_gst_hst: the province the registrant operates from, e.g. CA-ON. Not accepted for other regimes. Pattern: `"^CA-[A-Z]{2}$"`. |
| `effectiveFrom` | string | Yes | The effective date of registration the authority confirmed. Format: date. Example: `"2026-01-01"`. |
| `reason` | string | Yes |  Minimum length: `1`. Maximum length: `1000`. Example: `"VAT registration certificate received from HMRC"`. |

## After acceptance

When the command emits events, its documented effects and receipt are recorded in the command transaction. The response returns `commandId`, `replayed`, the command-specific `result` below and emitted `events` with their IDs and CIDs. A command is not automatically a cash movement or revenue recognition: use the behavior above to determine what this command records.

Inspect `result` and the affected records or reports before continuing. Save returned identifiers for later calls. Fetch `GET /v1/commands/{id}` with `commandId` to recover the accepted receipt; retry the same intent with the same idempotency key if the response was lost. Some commands can succeed with `events: []` and return a transient result and `commandId` without persisting a receipt. A lookup of that ID can return null; retain the returned result and verify the affected record. Retrying can re-evaluate the current state rather than replay a stored result. A domain `no_change` is a separate success outcome with no persisted receipt.

### Result fields

Required means required within its containing object; an optional parent can be omitted.

| Field | Type | Required | Meaning and accepted values |
|---|---|---|---|
| `registration` | object | Yes |   |
| `registration.registrationId` | string | Yes |   |
| `registration.regime` | string | Yes | sg_gst (Singapore GST); ca_gst_hst (Canadian GST/HST), ca_qst (Quebec QST), ca_pst_bc, ca_pst_sk, ca_rst_mb (provincial sales taxes, kept apart from GST/HST); gb_vat (UK VAT). It must be a regime of the country the business is incorporated in. There is no US regime: record US state sales tax as custom codes with tax_codes.create. Choose `"sg_gst"`, `"ca_gst_hst"`, `"ca_qst"`, `"ca_pst_bc"`, `"ca_pst_sk"`, `"ca_rst_mb"`, `"gb_vat"`. |
| `registration.country` | string | Yes |   |
| `registration.registrationNumber` | string | Yes |   |
| `registration.province` | string | No |   |
| `registration.effectiveFrom` | string | Yes |  Format: date. |
| `registration.effectiveUntil` | string | No |  Format: date. |
| `registration.reason` | string | Yes |   |
| `registration.sourceDocumentId` | string | Yes |   |
| `seededTaxCodes` | array | Yes |  Items: string. |


[All commands](/docs/command-reference/) · [Operation and errors](/docs/api-reference/operations/commands-execute/) · [Reusable schemas](/docs/api-reference/components/)

Keep credentials out of prompts; rehearse writes only in a disposable sandbox.

## Exact request schema


```json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "name": {
      "const": "business.register_sales_tax"
    },
    "input": {
      "type": "object",
      "required": [
        "regime",
        "registrationNumber",
        "effectiveFrom",
        "reason"
      ],
      "properties": {
        "regime": {
          "enum": [
            "sg_gst",
            "ca_gst_hst",
            "ca_qst",
            "ca_pst_bc",
            "ca_pst_sk",
            "ca_rst_mb",
            "gb_vat"
          ],
          "description": "sg_gst (Singapore GST); ca_gst_hst (Canadian GST/HST), ca_qst (Quebec QST), ca_pst_bc, ca_pst_sk, ca_rst_mb (provincial sales taxes, kept apart from GST/HST); gb_vat (UK VAT). It must be a regime of the country the business is incorporated in. There is no US regime: record US state sales tax as custom codes with tax_codes.create."
        },
        "registrationNumber": {
          "type": "string",
          "minLength": 1,
          "description": "As issued: a Singapore UEN or IRAS GST number (201912345K, M2-1234567-K); a Canadian BN with its RT account (123456789RT0001); a QST number (1234567890TQ0001); PST-1234-5678 (BC); a UK VAT number (GB123456789). Spaces are ignored."
        },
        "province": {
          "type": "string",
          "pattern": "^CA-[A-Z]{2}$",
          "description": "Required for ca_gst_hst: the province the registrant operates from, e.g. CA-ON. Not accepted for other regimes."
        },
        "effectiveFrom": {
          "type": "string",
          "format": "date",
          "description": "The effective date of registration the authority confirmed."
        },
        "reason": {
          "type": "string",
          "minLength": 1,
          "maxLength": 1000
        }
      },
      "additionalProperties": false
    },
    "idempotency_key": {
      "type": "string",
      "minLength": 1,
      "maxLength": 256
    },
    "effective_at": {
      "type": "string",
      "format": "date-time",
      "pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d+)?(?:Z))$"
    },
    "source_document_id": {
      "description": "A registered document of kind source_document that caused this command.",
      "type": "string",
      "minLength": 1
    }
  },
  "required": [
    "name",
    "input",
    "idempotency_key",
    "effective_at"
  ],
  "additionalProperties": false
}
```

## Accepted command receipt


```json
{
  "type": "object",
  "required": [
    "commandId",
    "replayed",
    "result",
    "events"
  ],
  "properties": {
    "commandId": {
      "type": "string"
    },
    "replayed": {
      "type": "boolean"
    },
    "imported": {
      "const": true,
      "description": "The command's events are history from before the business joined Economico, recorded as an import: free of monthly events."
    },
    "result": {
      "type": "object",
      "required": [
        "registration",
        "seededTaxCodes"
      ],
      "properties": {
        "registration": {
          "type": "object",
          "properties": {
            "registrationId": {
              "type": "string"
            },
            "regime": {
              "enum": [
                "sg_gst",
                "ca_gst_hst",
                "ca_qst",
                "ca_pst_bc",
                "ca_pst_sk",
                "ca_rst_mb",
                "gb_vat"
              ],
              "description": "sg_gst (Singapore GST); ca_gst_hst (Canadian GST/HST), ca_qst (Quebec QST), ca_pst_bc, ca_pst_sk, ca_rst_mb (provincial sales taxes, kept apart from GST/HST); gb_vat (UK VAT). It must be a regime of the country the business is incorporated in. There is no US regime: record US state sales tax as custom codes with tax_codes.create."
            },
            "country": {
              "type": "string"
            },
            "registrationNumber": {
              "type": "string"
            },
            "province": {
              "type": "string"
            },
            "effectiveFrom": {
              "type": "string",
              "format": "date"
            },
            "effectiveUntil": {
              "type": "string",
              "format": "date"
            },
            "reason": {
              "type": "string"
            },
            "sourceDocumentId": {
              "type": "string"
            }
          },
          "required": [
            "registrationId",
            "regime",
            "country",
            "registrationNumber",
            "effectiveFrom",
            "reason",
            "sourceDocumentId"
          ]
        },
        "seededTaxCodes": {
          "type": "array",
          "items": {
            "type": "string"
          }
        }
      }
    },
    "events": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "id": {
            "type": "integer"
          },
          "cid": {
            "type": "string"
          }
        }
      }
    }
  }
}
```

## Example request


```json
{
  "name": "business.register_sales_tax",
  "input": {
    "regime": "gb_vat",
    "registrationNumber": "GB123456789",
    "effectiveFrom": "2026-01-01",
    "reason": "VAT registration certificate received from HMRC"
  },
  "effective_at": "2026-09-01T00:00:00Z",
  "idempotency_key": "business.register_sales_tax-example-0"
}
```

## Example request


```json
{
  "name": "business.register_sales_tax",
  "input": {
    "regime": "ca_gst_hst",
    "registrationNumber": "123456789RT0001",
    "province": "CA-ON",
    "effectiveFrom": "2026-01-01",
    "reason": "Registered for GST/HST with the CRA"
  },
  "effective_at": "2026-09-01T00:00:00Z",
  "idempotency_key": "business.register_sales_tax-example-1"
}
```