Bulk Creation

Send one batch call instead of a loop. The Admin API creates stock items, SKUs, customers and order lines from an array, and one call counts as one request against your API key allowance however many records it carries. Decide how many records the account needs before you create any. Individual tracking is a modelling decision, not a volume decision.

Decide the shape first

Ask whether each unit needs its own history.

Each unit needs	Create	Result
Its own code, condition, service history, income and costs	One tracked stock item per unit	`N` records, each with its own timeline
Nothing of its own, because any unit will do	One stock item that carries the quantity	One record covering `N` units

A hire fleet of 40 bikes needs 40 records: each frame carries a serial number, its own servicing and its own repair costs. A resale listing for 1,000 identical t-shirts needs one record with a quantity of 1,000. Choosing per-unit records for interchangeable stock gives the account 1,000 rows to scroll where one would do, and spreads availability arithmetic across records that never needed separating. Set the mode with trackIndividually on the create request. Read Inventory tracking for what each mode reports and what it gives up.

How it works

Four endpoints accept an array:

Endpoint	Creates	One array entry is
`POST /v1/admin/articles/create-many`	Stock items	One stock item
`POST /v1/admin/skus/many`	SKUs	One SKU
`POST /v1/admin/customers/many`	Customers	One customer, matched on email
`POST /v1/admin/orders/{orderId}/lineItems/create-many`	Line items on one existing order	One line

Each entry creates exactly one record. On articles/create-many, quantity sets that one record’s capacity: it never multiplies entries, and trackIndividually is read on the single create only. So there are two ways to create many stock items, and they answer different questions:

Same item, many tracked units. Call POST /v1/admin/articles once with quantity. Every unit becomes its own record.
Units that differ in name, SKU, location or attributes. Call POST /v1/admin/articles/create-many with one entry per record.

Usage

Stock items

Create 40 tracked bikes in one call. codes assigns the first code to the first unit, the second to the second, and generates a code for any unit you leave uncovered.

curl -X POST https://server.twicecommerce.com/v1/admin/articles \
  -H "X-API-KEY: {key}" \
  -H "Content-Type: application/json" \
  -d '{
    "article": {
      "name": "Trail bike 29\"",
      "serviceLocationId": "9f1c2d84-4c1e-4a0b-9b62-3a7e5c118d20",
      "taxonomyCategoryId": null,
      "quantity": 40,
      "trackIndividually": true,
      "codes": ["BIKE-001", "BIKE-002", "BIKE-003"]
    }
  }'

[
  {
    "id": "3c8a5f21-0e9d-4a17-9c33-6b2f0d51a884",
    "name": "Trail bike 29\"",
    "status": "active",
    "codes": ["BIKE-001"],
    "quantity": { "total": 1 }
  },
  {
    "id": "b71d0c46-2f83-4d59-8a05-9e4c7a1b3f62",
    "name": "Trail bike 29\"",
    "status": "active",
    "codes": ["BIKE-002"],
    "quantity": { "total": 1 }
  }
]

For interchangeable stock, send trackIndividually: false and the same quantity. One record comes back with quantity.total set to 40. Use create-many when the entries differ from each other:

curl -X POST https://server.twicecommerce.com/v1/admin/articles/create-many \
  -H "X-API-KEY: {key}" \
  -H "Content-Type: application/json" \
  -d '[
    {
      "name": "Meeting room chair",
      "serviceLocationId": "9f1c2d84-4c1e-4a0b-9b62-3a7e5c118d20",
      "taxonomyCategoryId": null,
      "quantity": 120,
      "codes": ["CHAIR-POOL-A"]
    },
    {
      "name": "Wool coat, size M",
      "serviceLocationId": "5d2b6e07-1a44-4f8c-bb90-2c6d3e7f4a15",
      "taxonomyCategoryId": null,
      "codes": ["RESALE-2026-0184"]
    }
  ]'

[
  {
    "id": "e0a4b913-77c6-42de-9f1a-08b5c2d63417",
    "name": "Meeting room chair",
    "status": "active",
    "codes": ["CHAIR-POOL-A"],
    "quantity": { "total": 120 }
  },
  {
    "id": "1f6c8d25-93ab-4e07-8c14-5a9b0e3d7268",
    "name": "Wool coat, size M",
    "status": "active",
    "codes": ["RESALE-2026-0184"],
    "quantity": { "total": 1 }
  }
]

SKUs

POST /v1/admin/skus/many creates one SKU per entry and returns the id, name and code of each. Omit code and TWICE generates one from the name, adding a numeric suffix until it is unique in the account. Send a code that already exists and the call fails with 400, naming the code. Nothing is created when it fails: the whole array is written in one transaction.

curl -X POST https://server.twicecommerce.com/v1/admin/skus/many \
  -H "X-API-KEY: {key}" \
  -H "Content-Type: application/json" \
  -d '[
    { "name": "Trail bike 29\"", "code": "TRA-BI-29" },
    { "name": "Studio A" }
  ]'

[
  { "id": "a2d47e19-6c30-4b85-9f27-0e1a8d5c3b46", "name": "Trail bike 29\"", "code": "TRA-BI-29" },
  { "id": "7b93f0c5-8d21-4a6e-b013-4c5f2e9a7d81", "name": "Studio A", "code": "ST-A" }
]

Customers

POST /v1/admin/customers/many returns one id per entry. An entry whose email already exists on the account updates that customer instead of creating a second one, and fields you leave out keep their stored values. Entries without an email are always inserted, so a repeated import without emails builds duplicates.

curl -X POST https://server.twicecommerce.com/v1/admin/customers/many \
  -H "X-API-KEY: {key}" \
  -H "Content-Type: application/json" \
  -d '[
    { "firstName": "Aino", "lastName": "Virtanen", "email": "aino@example.com", "marketingConsent": true },
    { "firstName": "Marek", "lastName": "Novak", "email": "marek@example.com", "marketingConsent": false }
  ]'

{
  "ids": [
    "c41e7b26-9a58-4d03-8f16-2b7d0c5e9a34",
    "8d2f5a70-3c19-4be8-a742-6f0b1d8c37e5"
  ]
}

Order line items

POST /v1/admin/orders/{orderId}/lineItems/create-many adds several lines to one existing order. Each line carries its own quantity, so identical lines do not need one entry each. Prices are computed server-side from the catalog item and pricing row.

curl -X POST https://server.twicecommerce.com/v1/admin/orders/6e0f3b74-52a8-4c19-9d75-8b1e4a2c6f03/lineItems/create-many \
  -H "X-API-KEY: {key}" \
  -H "Content-Type: application/json" \
  -d '[
    {
      "catalogItemId": "d5b81f39-7a02-4c68-9e14-3f7a5c0b28d6",
      "pricingRowId": "2a7c6e40-8b13-49f5-a0d2-7c9e5b1f3a48",
      "purchaseType": "booking",
      "quantity": 12,
      "startDate": "2026-10-02T08:00:00.000Z",
      "endDate": "2026-10-02T16:00:00.000Z"
    }
  ]'

[
  {
    "id": "9c3a7d18-4b65-42f0-8e29-1d6b0a5c7e93",
    "catalogItemId": "d5b81f39-7a02-4c68-9e14-3f7a5c0b28d6",
    "purchaseType": "booking",
    "quantity": 12,
    "startDate": "2026-10-02T08:00:00.000Z",
    "endDate": "2026-10-02T16:00:00.000Z"
  }
]

Check codes and emails before you send

Run the validation endpoint over the whole list first and resolve the clashes up front. Each returns only the entries that would fail, so an empty invalid array means the batch is free to go.

Run this	It returns
`POST /v1/admin/articles/validate-codes` with `{ "codes": [...] }`	Stock item codes already in use, each with `reason: "existing"`
`POST /v1/admin/skus/validate-codes` with `{ "codes": [...] }`	SKU codes already in use
`POST /v1/admin/customers/validate-emails` with `{ "emails": [...] }`	Emails already on a customer, which the import would merge into

Batch size and rate limits

One call is one request. A loop of 1,000 single creates spends 1,000 requests of the key’s per-second rate and monthly cap; the same import as batch calls spends a handful. See the rate limits section of API keys for the three layers and the response headers that report what is left. The API declares no maximum on array length or on quantity, so nothing rejects a request to create ten million records. Treat a few hundred to around a thousand entries per call as guidance rather than a limit, and split a larger import into several calls. Splitting also keeps a failure cheap to recover from. SKUs and customers are written in one transaction, so a rejected entry leaves nothing behind. A very large stock item array is committed in parts, so entries early in the array can exist while a later one fails. Send batches you can retry, and record which ones came back 200.

Not every import needs the API. The admin imports stock items and customers from a CSV file, which is usually the faster route for a one-off migration. See Import inventory from CSV and Import customers.

Inventory tracking

Serialized and pooled tracking, and what each one reports.

Stock item vs SKU

Which of the two a record should be.

API keys

Authentication, API versions and rate limits.

API: Articles

Every stock item endpoint and its schema.

Welcome to TWICE Docs

Navigating in TWICE

Understand the system

Decide the shape first

How it works

Usage

Stock items

SKUs

Customers

Order line items

Check codes and emails before you send

Batch size and rate limits

Inventory tracking

Stock item vs SKU

API keys

API: Articles

​Decide the shape first

​How it works

​Usage

​Stock items

​SKUs

​Customers

​Order line items

​Check codes and emails before you send

​Batch size and rate limits

​Related articles

Inventory tracking

Stock item vs SKU

API keys

API: Articles

Decide the shape first

How it works

Usage

Stock items

SKUs

Customers

Order line items

Check codes and emails before you send

Batch size and rate limits

Related articles