> For the complete documentation index, see [llms.txt](https://chekin.gitbook.io/chekin-public-api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chekin.gitbook.io/chekin-public-api/api-reference/einvoicing/suppliers.md).

# Suppliers

A supplier is the invoice issuer: it stores the company information, tax details, credentials and invoice issuance settings used to produce documents for a property.

### Suggested workflow for creating suppliers

1. Prepare supplier data with all common required fields:
   1. `initial_housing_id`, `name`, `vat_number`
   2. `provider`, `country`
   3. `street`, `building_number`, `city`, `postal_code`
   4. `payment_method`, `tax_category_key`
2. Add the [provider-specific fields](/chekin-public-api/api-reference/einvoicing/suppliers/create-new-supplier.md#provider-specific-fields):
   1. **MyData** — `data["gr-mydata-other-tax"]`
   2. **AT** — no extra mandatory fields
   3. **AADE** — `aade_username`, `aade_password`, `external_housing_id`
   4. **AdE** — `province`, `data.legal_storage.email`
3. Select the correct `tax_category_key` for your provider (see [Tax Category Keys](/chekin-public-api/api-reference/einvoicing/suppliers/create-new-supplier.md#tax-category-keys-taxcategorykey-per-provider)).
4. Configure the `series` array (not applicable for AADE). It is recommended to create all supported series types upfront so you can issue all kinds of documents without updating the supplier later:
   1. `STANDARD` – for standard invoices
   2. `CREDIT_NOTE` – for credit notes
   3. `RECEIPT` – for receipts
   4. `RETAIL_SALES_CREDIT_NOTE` – for cancelling receipts
5. (Optional) Configure `webhook_configurations` to be notified of `CREATED`, `COMPLETED` and `FAILED` events — see [Invoice webhooks](/chekin-public-api/api-reference/einvoicing/webhooks/invoice-webhooks.md).
6. Send the `POST` request.
7. Store the following values from the response:
   1. `supplier_id` for further operations
   2. `series_id` of the required type for issuing invoices

{% hint style="info" %}
For MyData and AT, a **workspace** (the connection to the Invopop platform) is created automatically during supplier creation and returned in the response. See [Check workspace availability](/chekin-public-api/api-reference/einvoicing/suppliers/check-workspace-availability.md).
{% endhint %}