API reference

GET /api/v1/me

Who this key belongs to, and what it can do

Returns the account the key is attached to, its plan, and the capabilities of the API. Useful as a connection test.

Example request

curl https://quarterwise.co.uk/api/v1/me \
  -H "Authorization: Bearer qw_live_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d"

Example response (200)

{
  "accountId": "0d4f3c1a-8b2e-4d5f-9a6c-2f7e8b9c0d1e",
  "plan": "pro",
  "capabilities": {
    "readBookkeeping": true,
    "writeBookkeeping": true,
    "hmrcSubmission": false
  },
  "note": "Submitting to HMRC is not available through the API. Quarterly updates and the tax return are confirmed and sent by the account holder in the browser."
}

GET /api/v1/sources

List the account’s properties and businesses

Every income source on the account: UK properties, overseas properties and self-employment businesses. The id is what you pass to the transactions endpoints.

sharePercent is the account holder’s share of a jointly held property, as a percentage. transactionCount is the number of ledger entries currently recorded against the source.

Example request

curl https://quarterwise.co.uk/api/v1/sources \
  -H "Authorization: Bearer qw_live_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d"

Example response (200)

{
  "sources": [
    {
      "id": "6a1f9b3e-4c2d-4e8f-b1a7-5d9c0e2f4a6b",
      "name": "14 Brookfield Road",
      "type": "uk-property",
      "countryCode": null,
      "role": "owner",
      "sharePercent": 100,
      "transactionCount": 128
    },
    {
      "id": "8c3e5d7f-2a4b-4c6d-8e0f-1b3d5f7a9c2e",
      "name": "Flat 2, Sea View",
      "type": "uk-property",
      "countryCode": null,
      "role": "sharer",
      "sharePercent": 50,
      "transactionCount": 41
    },
    {
      "id": "2f7c4a9d-1e3b-4d5c-a8f0-6b2e9d4c1a7f",
      "name": "Villa Rosa",
      "type": "foreign-property",
      "countryCode": "ES",
      "role": "owner",
      "sharePercent": 100,
      "transactionCount": 23
    },
    {
      "id": "4b9e2d6f-8a1c-4f3e-b5d7-0c8a6e2f4b9d",
      "name": "Joinery and carpentry",
      "type": "self-employment",
      "countryCode": null,
      "role": "owner",
      "sharePercent": 100,
      "transactionCount": 57
    }
  ]
}

GET /api/v1/categories

Valid category keys, per source type

The category keys accepted when posting transactions. Keys are HMRC’s own field names, and they differ by source type: a key that is valid for a UK property may not be valid for an overseas property or a self-employment business.

With no sourceType parameter the response covers all three source types, keyed by type. The example below is the real, current response with no parameter.

Parameters

Example request

curl https://quarterwise.co.uk/api/v1/categories \
  -H "Authorization: Bearer qw_live_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d"

Example response (200)

{
  "uk-property": {
    "income": [
      {
        "key": "periodAmount",
        "label": "Rent received"
      },
      {
        "key": "premiumsOfLeaseGrant",
        "label": "Lease premiums"
      },
      {
        "key": "reversePremiums",
        "label": "Reverse premiums"
      },
      {
        "key": "otherIncome",
        "label": "Other property income"
      },
      {
        "key": "rentARoomRentsReceived",
        "label": "Rent a Room — rents received"
      },
      {
        "key": "taxDeducted",
        "label": "Tax withheld from rent"
      }
    ],
    "expense": [
      {
        "key": "premisesRunningCosts",
        "label": "Rent, rates, insurance, ground rents"
      },
      {
        "key": "repairsAndMaintenance",
        "label": "Repairs & maintenance"
      },
      {
        "key": "financialCosts",
        "label": "Other finance costs"
      },
      {
        "key": "residentialFinancialCost",
        "label": "Residential mortgage interest"
      },
      {
        "key": "professionalFees",
        "label": "Legal, management & professional fees"
      },
      {
        "key": "costOfServices",
        "label": "Cost of services"
      },
      {
        "key": "travelCosts",
        "label": "Travel"
      },
      {
        "key": "other",
        "label": "Other allowable expenses"
      },
      {
        "key": "residentialFinancialCostsCarriedForward",
        "label": "Residential finance costs brought forward"
      },
      {
        "key": "rentARoomAmountClaimed",
        "label": "Rent a Room — amount claimed"
      }
    ]
  },
  "foreign-property": {
    "income": [
      {
        "key": "rentIncome",
        "label": "Rent received (overseas)"
      },
      {
        "key": "premiumsOfLeaseGrant",
        "label": "Lease premiums"
      },
      {
        "key": "otherPropertyIncome",
        "label": "Other property income"
      },
      {
        "key": "foreignTaxPaidOrDeducted",
        "label": "Foreign tax paid on this income"
      },
      {
        "key": "specialWithholdingTaxOrUkTaxPaid",
        "label": "Special withholding or UK tax paid"
      }
    ],
    "expense": [
      {
        "key": "premisesRunningCosts",
        "label": "Rent, rates, insurance, ground rents"
      },
      {
        "key": "repairsAndMaintenance",
        "label": "Repairs & maintenance"
      },
      {
        "key": "financialCosts",
        "label": "Other finance costs"
      },
      {
        "key": "residentialFinancialCost",
        "label": "Residential mortgage interest"
      },
      {
        "key": "professionalFees",
        "label": "Legal, management & professional fees"
      },
      {
        "key": "costOfServices",
        "label": "Cost of services"
      },
      {
        "key": "travelCosts",
        "label": "Travel"
      },
      {
        "key": "other",
        "label": "Other allowable expenses"
      },
      {
        "key": "broughtFwdResidentialFinancialCost",
        "label": "Residential finance costs brought forward"
      }
    ]
  },
  "self-employment": {
    "income": [
      {
        "key": "turnover",
        "label": "Sales and business income"
      },
      {
        "key": "other",
        "label": "Other business income"
      },
      {
        "key": "seTaxDeducted",
        "label": "Tax withheld from pay (CIS)"
      }
    ],
    "expense": [
      {
        "key": "costOfGoods",
        "label": "Cost of goods or materials"
      },
      {
        "key": "paymentsToSubcontractors",
        "label": "Payments to subcontractors"
      },
      {
        "key": "wagesAndStaffCosts",
        "label": "Wages and staff costs"
      },
      {
        "key": "carVanTravelExpenses",
        "label": "Car, van and travel"
      },
      {
        "key": "premisesRunningCosts",
        "label": "Rent, rates, power and insurance"
      },
      {
        "key": "maintenanceCosts",
        "label": "Repairs and maintenance"
      },
      {
        "key": "adminCosts",
        "label": "Phone, stationery and admin"
      },
      {
        "key": "advertisingCosts",
        "label": "Advertising and marketing"
      },
      {
        "key": "interestOnBankOtherLoans",
        "label": "Bank and loan interest"
      },
      {
        "key": "professionalFees",
        "label": "Accountancy, legal and professional fees"
      },
      {
        "key": "otherExpenses",
        "label": "Other allowable business expenses"
      }
    ]
  }
}

Endpoint errors

GET /api/v1/sources/{id}/transactions

List transactions for a source

Ledger entries for one source, newest first. Pagination is cursor-based: when there are more results, nextCursor is set; pass it back as the cursor parameter to fetch the next page. On the last page nextCursor is null.

category is null for entries that have not been categorised yet, and description and externalRef are null when they were not provided.

Parameters

Example request

curl "https://quarterwise.co.uk/api/v1/sources/6a1f9b3e-4c2d-4e8f-b1a7-5d9c0e2f4a6b/transactions?from=2026-04-06&limit=2" \
  -H "Authorization: Bearer qw_live_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d"

Example response (200)

{
  "transactions": [
    {
      "id": "f3a9c1e5-7b2d-4f6a-8c0e-9d1b3f5a7c9e",
      "date": "2026-05-14",
      "type": "expense",
      "category": "repairsAndMaintenance",
      "amountPence": 8450,
      "description": "Boiler service",
      "externalRef": null
    },
    {
      "id": "e2b8d0f4-6a1c-4e5b-9d7f-8c0a2e4b6d8f",
      "date": "2026-05-01",
      "type": "income",
      "category": "periodAmount",
      "amountPence": 95000,
      "description": "May rent",
      "externalRef": "may-rent-2026"
    }
  ],
  "nextCursor": "e2b8d0f4-6a1c-4e5b-9d7f-8c0a2e4b6d8f"
}

nextCursor is null when there are no further pages.

Endpoint errors

POST /api/v1/sources/{id}/transactions

Add transactions to a source

Creates ledger entries. The body is either a single transaction object or an array of up to 500.

Idempotent on externalRef: re-posting a ref that already exists in the account’s books returns the existing entry instead of creating a duplicate, so a retried import cannot double-count income. Always set externalRef if your system has its own ids.

If category is set it must be a valid key for the source’s type (see GET /api/v1/categories) and the entry is recorded as confirmed. If it is omitted the entry goes to the app’s review queue for the account holder to categorise.

Parameters

Example request

curl -X POST https://quarterwise.co.uk/api/v1/sources/6a1f9b3e-4c2d-4e8f-b1a7-5d9c0e2f4a6b/transactions \
  -H "Authorization: Bearer qw_live_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d" \
  -H "Content-Type: application/json" \
  -d '[
    {"date":"2026-05-01","type":"income","amountPence":95000,
     "category":"periodAmount","description":"May rent","externalRef":"may-rent-2026"},
    {"date":"2026-05-14","type":"expense","amountPence":8450,
     "category":"repairsAndMaintenance","description":"Boiler service","externalRef":"boiler-2026-05"}
  ]'

Example response (201)

{
  "created": 2,
  "deduplicated": 0,
  "transactions": [
    {
      "id": "e2b8d0f4-6a1c-4e5b-9d7f-8c0a2e4b6d8f",
      "externalRef": "may-rent-2026"
    },
    {
      "id": "f3a9c1e5-7b2d-4f6a-8c0e-9d1b3f5a7c9e",
      "externalRef": "boiler-2026-05"
    }
  ],
  "existing": []
}

Status is 201 when at least one entry was created, 200 when everything was deduplicated. Entries matched by externalRef appear in existing with their stored ids, and are counted in deduplicated.

Endpoint errors