API

REST API encrypted using the HTTPS protocol

HTTP Methods

• GET - returns data - does not make changes
• POST - sends new data
• PUT - updates data
• DELETE - deletes data

HTTP Codes

• 200 - OK
• 400 - Bad Request
• 401 - Unauthorized
• 404 - Not Found
• 409 - Conflict
• 422 - Unprocessable Entity - Data validation error
• 500 - Server Error

Preview of response 422 - Unprocessable Entity

{
  "status": "error",
  "code": 422,
  "message": "Request body contains an error. See context for details.",
  "context": {
	"validation": {
	  "productBarcodes": [
		"This value should not be blank."
	  ],
	  "productImagesUrl": [
		"This value should not be blank."
	  ]
	}
  }
}

Data JSON

Any data in the JSON format and UTF-8 encoding. Header Content-Type: application/json

Data types

You can find all data types of individual attributes of the request body in the description of each EP, in the section Request Body, link Schematics. Optional attributes are tagged with the flag nullable

API EP

Production: https://app.log4u.cz/

Request authorization

Step-by-step instructions for integrating the individual parts of the API. The description of all fields and the possibility to try the calls are in the interactive documentation below, lists of values in the List of values section.

Received orders (partner-orders)

Version 2 (20 Oct 2026) – PUT method as the recommended way to create and update orders, statuses evaluated every 15 minutes.

What it is for

Send us the order your customer placed with you right after you receive it – before you create the outcome order. The warehouse uses it to find out which goods on your income receipts are already awaited and not in stock, and receives such goods with priority. Your orders are therefore dispatched faster.

A received order does not reserve or dispatch anything. Dispatch is still triggered only by the outcome order you send as before.

How to proceed (recommended way)

1. Your customer places an order → send the whole order: PUT /api/v1/partner-orders/{order number}.
2. When the order changes (different quantity, different courier, cancelled or added item), send the whole current order again with the same PUT call under the same number. You do not need to remember what you sent before or compare the differences – Log4U compares the stored order itself: it adds new items, updates changed quantities, cancels items missing in the body and replaces the header data. Everything happens at once; if the request contains an error (e.g. an unknown product), the stored order stays unchanged.
3. When your customer cancels the order, send the cancellation: DELETE /api/v1/partner-orders/{number}/cancel.
4. When you dispatch the order, create the outcome order as before, with the same order number (externalId). The received order is paired with the outcome order by this number and gets the status “Shipped” after dispatch.
5. You can check the order status at any time – individually, or in bulk as all changes since a given time.

Authentication is the same as for the other API endpoints (headers Client-Key and Authorization-Token; the token is calculated from the HTTP method, i.e. from the string PUT for PUT).

Endpoints

Base https://app.log4u.cz/api/v1

Recommended:

• PUT /partner-orders/{externalId} – create or replace the whole order (does not exist → created, response 201; exists and is not shipped → replaced, 200; no change → nothing is written, 200)
• DELETE /partner-orders/{externalId}/cancel – cancel the whole order
• GET /partner-orders/{externalId} – detail with statuses
• GET /partner-orders – bulk listing (filters status, externalIds, createdFrom, createdTo, changedSince, includeItems, limit, offset)

Alternative for partial changes (no need to implement if you use PUT):

• POST /partner-orders – create an order including items (409 if the number already exists)
• PATCH /partner-orders/{externalId} – change courier, country or ZIP
• POST /partner-orders/{externalId}/items – add items
• PATCH /partner-orders/{externalId}/items/{sku} – change item quantity
• DELETE /partner-orders/{externalId}/items/{sku} – cancel an item

Order data

• externalId – your order number, 2–20 characters (letters, digits, -, _). It must be the same as the number of the later outcome order. The number is unique in your account; a cancelled order cannot be reopened or created again under the same number, use a new number. With PUT the number is in the URL, in the body it is optional (if sent, it must match).
• courierId – courier from the list of your allowed couriers (as for the outcome order).
• destinationCountry – delivery country code, e.g. CZ.
• destinationZip – ZIP code, optional.
• items – items: sku (product code, EAN or external ID – as for the outcome order) and quantity (positive integer). Required with PUT, at least one item.

Example body (PUT /partner-orders/OBJ-2026-001 as well as POST /partner-orders):

{
  "externalId": "OBJ-2026-001",
  "courierId": 12,
  "destinationCountry": "CZ",
  "destinationZip": "60200",
  "items": [
    { "sku": "ABC-1", "quantity": 4 },
    { "sku": "SET-10", "quantity": 2 }
  ]
}

Rules

• Each product is on the order only once. More pieces = a different quantity of the same item.
• Sets are split into individual products as in the outcome order (number of sets × pieces in the set). In the response a set is returned as one item with a components breakdown. Always change the quantity or cancel the whole set, not its parts.
• An order can be changed or cancelled until it is shipped. After a quantity change the item is evaluated again.
• Repeated cancellation of an already cancelled order is harmless (returns success).

Statuses

Returned for the order and for each item.

• created – Created: we have received the order, the warehouse has not evaluated it yet
• waiting_for_goods – Waiting for goods: the goods are neither in stock nor on any of your income receipts
• waiting_for_receipt – Waiting for receipt: the goods are on your income receipt, the warehouse will receive them with priority
• cleared – Cleared: the ordered quantity is in stock
• shipped – Shipped: the outcome order with the same number was dispatched
• cancelled – Cancelled

The order status corresponds to the least advanced of its items. The warehouse evaluates the statuses continuously, roughly every 15 minutes – a change is therefore not visible immediately. For regular polling of changes we recommend the bulk listing with the changedSince parameter (just pass the time of your last request).

Responses and errors

• 201 / 200 – OK, returns the current order status
• 404 – the order, product or item does not exist
• 409 – conflict (number already used, courier not allowed, unknown product, product already on the order, order can no longer be changed – shipped or cancelled)
• 422 – invalid request (missing or invalid value)

The error text always says exactly what is wrong.

Test mode: orders are stored and can be worked with, but the warehouse does not evaluate them – they stay in the created status.

Order (outcome order) import errors

Version 2 (31 Oct 2026) – the import response carries the errorCode for each error; added the shape of error responses and a dictionary of import messages with codes and what to do.

Where to find the errors

• Import response POST /api/v1/pick/import – returns HTTP 200 even if some order was not created. Created orders are listed in vydejkyImportedIds, errors in errors (order number, error text and the error code errorCode).
• Application – menu Tasks - Communication → Import errors (filter, state change, export). The e-mail import summary links to this overview too.
• API – GET /api/v1/import-error/list (default filter state=open, further errorCode, externalId, source, dateFrom, dateTo), detail GET /api/v1/import-error/{id}, state change PATCH /api/v1/import-error/{id}/state.

The overview covers imports via API and from connected e-shops. One record = source + order number + error code; a repeated occurrence increases the occurrence count. When the order is later imported successfully, its open errors are resolved automatically.

What an error response looks like

1. The import ran, but some order was not created – HTTP 200. Errors are in the errors field: sourceId = order number (externalId), msg = error text, errorCode = error code from the table below (null for the informative test mode message). React to errors by errorCode – the message text is meant for people and may be refined. One order can have several errors at once (e.g. all unknown products and all items without stock). An order listed in errors was not created – except for the Step6 message, see the message dictionary below.

{
  "vydejkyImportedCount": 1,
  "vydejkyImportedIds": ["2616054100"],
  "errors": [
    {
      "sourceId": "2616054101",
      "msg": "Step3 - Cannot create vydejka (2616054101). Item (QS19133A) does not have enough stock. Current quantity in stock is 0. Requested quantity in stock was 1",
      "errorCode": "insufficient_stock"
    },
    {
      "sourceId": "2616054102",
      "msg": "Step2 - Cannot create vydejka (2616054102). Order has no items",
      "errorCode": "missing_items"
    }
  ]
}

2. The request was not processed at all – HTTP 4xx / 5xx

The response body contains status, code (HTTP code) and message (error text):

{
  "status": "error",
  "code": 401,
  "message": "Invalid request token or headers"
}

Error codes (errorCode)

Dictionary of order import messages

The error text in errors[].msg starts with the import step in which the order failed (Step1 order number and account, Step2 items, Step3 stock and sets, Step4 delivery data and carrier, Step5 saving, Step6 handover to dispatch). The code in the third column is the value of errors[].errorCode in the response, and the same code is shown in the application (Import errors) and in GET /api/v1/import-error/list. Messages shown in two languages come in the language of your account (Czech or English), all others always in English. Variable parts (order number, product code, quantity…) are in italics. Step4 messages are preceded by Step4 - [Validator Error.] Cannot create vydejka (…) Cannot create address for vydejka (…) address … with Error:.

Order status in the response (status, stockStatus)

GET /api/v1/pick/{externalId} and POST /api/v1/pick/batch return two statuses:

• status – document status in the warehouse system, e.g. wait (created, waiting to be scheduled), wpkin, pking, pked, exped, str (cancelled).
• stockStatus – simplified status for you (0 Created, 1 Waiting for picking … 1000 Cancelled); the full list is in the List of values section, Stock outcome order - List of stock statuses.

wait + stockStatus 0 means the order is created but the warehouse has not scheduled it for processing yet. If an order stays like this for a long time, it may have been created without items – since 31 Oct 2026 an order without items is no longer created and the import returns the error missing_items.

How to send again

• The import is atomic per order: on an error the given order is not created at all, other orders in the batch are processed normally.
• After fixing, send the same order with the same number again – the open error is resolved automatically after a successful import.
• Always send the complete order including items and delivery; do not send an order without items.
• If the response returns duplicate_order, the order already exists – check it via GET /api/v1/pick/{externalId}.