# Checkbox + Krokul CRM

Yes. Krokul CRM integrates with Checkbox. Krokul creates a fiscal receipt in the Checkbox software cash register (PRRO) as soon as a deal payment is marked as received. Items and amounts come from the invoice, and the buyer gets the receipt by email or SMS. The fiscal number and the PDF come back to Krokul through a Checkbox webhook and land on the payment.

**Status:** Via API and webhooks.

## What your team gets

### A received payment becomes a receipt at once

The accountant marks a deal payment as received, and Krokul calls POST /api/v1/receipts/sell. The goods field gets the names, prices and quantities from the invoice, payments gets the amount and payment type, and order_id gets the Krokul document number. If the cashier shift is closed, Krokul opens it before the first receipt of the day.

### The buyer gets the receipt by email

The delivery block of the request takes the email from the deal contact. For clients who left only a phone number, Krokul sends the receipt with the /receipts/{id}/sms method. The manager forwards nothing by hand and sees in the deal feed where the receipt went.

### The fiscal number on the payment

After fiscalization, Checkbox sends a webhook to the Krokul connection address. Krokul checks the x-request-signature header, finds the deal by order_id and writes the fiscal number to the payment. A link to the receipt PDF from /receipts/{id}/pdf appears in the deal files.

### A refund with a return receipt

When a payment refund is made in Krokul, a return receipt is created with the same receipts/sell method and the is_return flag on the items. Both receipts are visible on the same deal.

### The cash register log next to sales

The Checkbox webhook also reports shift openings and closings and service cash deposits and withdrawals. Krokul puts these events into the connection log and closes the shift on the schedule you set.

## What moves between Checkbox and Krokul

| Checkbox | Krokul | Direction | When |
|---|---|---|---|
| Sale receipt (receipts/sell): goods, payments, order_id | Payment and invoice lines | Krokul → Checkbox | The payment is marked as received |
| Receipt delivery (delivery, /email, /sms) | Email or phone of the deal contact | Krokul → Checkbox | In the receipt request |
| Cashier shift (shifts, shifts/close) | Connection settings | Krokul → Checkbox | Before the first receipt and on the closing schedule |
| Receipt fiscalization webhook | Fiscal number on the payment, entry in the deal feed | Checkbox → Krokul | After fiscalization |
| Receipt PDF (/receipts/{id}/pdf) | Deal file | Checkbox → Krokul | After fiscalization |
| Return receipt (goods with is_return) | Payment refund | Krokul → Checkbox | When a refund is made |
| Webhook on shift opening and closing, deposits and withdrawals | Connection log | Checkbox → Krokul | While the cash register works |

## How to connect today

### Your own flow through the Krokul API and webhooks

1. On my.checkbox.ua, set up a point of sale, a cash register and a cashier, get the cash register license key and prepare the receipt signing key (a QES key file or the cloud DepositSign).
2. In Krokul, issue an API key with scopes for payments and documents, and subscribe your address to the `payment.received` event through `webhook/api-upsert`. Check the `x-crm-signature` header of every delivery against your secret.
3. On the event, sign the cashier in with /cashier/signin, open a shift if needed and call /receipts/sell with the invoice lines that `document/api-read` returns.
4. Register your address for Checkbox webhooks (POST /api/v1/webhook). Write the fiscal number from the webhook to the deal feed with `activity/api-create`, and link the receipt id to the payment with `externalRef/api-set`.

### For integrators

Checkbox publishes an open specification in OpenAPI, Swagger and ReDoc on api.checkbox.in.ua. The Checkbox webhook retries for up to four hours, and Krokul accepts it idempotently by receipt id. The same payments are available in the Krokul public API, the `payment.received` and `invoice.paid` events arrive as signed webhooks with a delivery log, and a sandbox with demo data lets you test the setup.

[API documentation](https://app.krokul.com/api/v1/docs)

## Questions and answers

### Does Krokul have a Checkbox integration?

Yes. Krokul integrates with Checkbox through its API and webhooks. Krokul issues a receipt in Checkbox for a received payment, sends it to the buyer and keeps the fiscal number and the receipt PDF on the deal.

### What do I need to connect Checkbox?

A cash register in the Checkbox account with a license key, a cashier with a login and password, and a signing key (a QES key file or the cloud DepositSign).

### Does every payment in Krokul become a receipt?

No, only the ones that match your rules. In the connection settings, you choose the payment forms and document types that are fiscalized.

### How does Krokul know that a receipt is fiscalized?

Checkbox sends a webhook to the Krokul connection address. Krokul checks the x-request-signature header and writes the fiscal number to the payment.

## Limits

A Checkbox receipt is signed with the cash register key (a QES key file or the cloud DepositSign), and it is issued on behalf of a cashier with an open shift. Your accountant checks that the receipt contents follow tax rules (VAT rates of items, payment form) in the cash register and item settings.

## Related services

- [Vchasno](https://krokul.com/en/integrations/vchasno/index.md)
- [monobank](https://krokul.com/en/integrations/monobank/index.md)
- [NovaPay](https://krokul.com/en/integrations/novapay/index.md)
- [WayForPay](https://krokul.com/en/integrations/wayforpay/index.md)

[Documents and fiscal (Ukraine)](https://krokul.com/en/integrations/category/documents-ua/index.md)

Checkbox is a trademark of its owner. Krokul is not affiliated with Checkbox.

Updated: 2026-10-15

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App: https://app.krokul.com/ · API: https://app.krokul.com/api/v1/docs