> For the complete documentation index, see [llms.txt](https://help.bizmachine.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.bizmachine.com/en/api-and-integrations/bulk-api-calls.md).

# Bulk API calls

How to page through results, filter by label or time period, and what to watch out for when you call the BizMachine API in bulk.

*Updated: 8 October 2026*

Some API endpoints (the collection endpoints) support bulk calls: one request returns data for multiple companies at once. The full list of endpoints and parameters is in the [API documentation](https://developers.bizmachine.com/).

### Paging through results

By default the API returns **200 records per page**. Use the `Limit` parameter to set the page size, up to a maximum of **250 records** *(as of October 2026)*. To get further pages, use the `Offset` parameter. `Offset` must be a multiple of the page size:

```
GET /cz/v3/events?Company.NationalIn=12345678&Limit=250&Offset=0      (page 1)
GET /cz/v3/events?Company.NationalIn=12345678&Limit=250&Offset=250    (page 2)
GET /cz/v3/events?Company.NationalIn=12345678&Limit=250&Offset=500    (page 3)
```

Without `Limit`, page in steps of 200 (`Offset=0`, `200`, `400`). If `Offset` is not a multiple of the page size, the API returns the error `ArgumentOutOfRangeException`. With the default page size, the message is "Offset has to be multiple of page size 200".

The response gives the total number of records in the `paging.totalItems` field. Keep paging until you have processed all records.

> **Watch out:** Use the `Offset` parameter, not `Page`. The API silently ignores `Page` and keeps returning the first page. The result is duplicate data with no error message.

### Most commonly used parameters

#### Tag.Uid and Company.Tag.Uid: filter by label

The API returns data only for the companies in the label (a list of companies) you specify. You can create the label directly in Prospector, or manage it entirely through the API.

A typical workflow: upload a list of companies into a label through the API, then call a data endpoint with a filter on that label. You get data only for those companies. The parameter name depends on the endpoint:

* **`Tag.Uid`**: company data endpoints, for example `basic-infos`, `contacts`, `metrics`, `indicators` and `owners`
* **`Company.Tag.Uid`**: the `events`, `financials/reports`, `job-postings` and `locations` endpoints

If you use the wrong name, the API silently ignores it and returns data for all companies (see below).

#### Updated.From, Updated.To: incremental updates

The API returns only the records that changed in the period you specify. In most cases it is enough to import all data once and then regularly request only the changes for the latest period.

### What to watch out for

* **The API silently ignores unknown parameters.** If you use a wrong parameter name (a typo, a wrong format), the API does not return an error. It returns unfiltered results. If you get an unexpectedly large number of records, check the parameter names.
* **Vehicles use a different identifier.** The `vehicles` endpoint does not use `Company.NationalIn`. It uses `Company.UniqueId` in the format `{dataset}-company-{ico}` (for example `cz-company-12345678`). See [Overview of API endpoints](/en/api-and-integrations/api-endpoints.md).
* **The maximum of 250 records per page applies to all collection endpoints** *(as of October 2026)*. The response shows it as `maxPageSize` in the `paging` section.

### More information

* [Overview of API endpoints](/en/api-and-integrations/api-endpoints.md)
* [What are my API limits?](/en/api-and-integrations/api-limits.md)
* [API documentation](https://developers.bizmachine.com/)