Catcode PRRO Connector — fiscal receipts (Vchasno.Kasa, Checkbox) for WooCommerce

Catcode PRRO Connector is a fiscalisation plugin for WooCommerce that links your shop to Ukrainian software cash registers (PRRO) and issues a fiscal receipt automatically the moment an order moves into a chosen status (for example “processing” after a LiqPay or Monobank payment). One plugin covers several PRRO services with fallback between them, manages the register shift and sends the receipt to the customer by email and SMS.

Supported PRRO services

• Vchasno.Kasa — full support: sale receipts, shift control, connection testing.
• Checkbox — an adapter built to the public API documentation.

You can assign a primary service and a backup (fallback): if the primary does not answer, the receipt automatically goes through the spare.

How it works, step by step

1. The customer pays through any gateway — LiqPay, Monobank, WayForPay and so on.
2. The gateway moves the order into “processing” with its callback.
3. The plugin catches the status change (woocommerce_order_status_changed) and sends the receipt data to the PRRO; if the register shift is closed, it opens the shift first and retries.
4. The PRRO returns a fiscal number — it is written into an order note and into the receipt log.
5. The customer gets the receipt: an email with a link to the PDF and, optionally, an SMS through TurboSMS.
6. Accounting takes the log of receipts with PDF/HTML links through the CSV export.

Separately: an “Issue receipt” button on the order screen, a list of payment methods fiscalised as cash (cash on delivery with Nova Poshta or Ukrposhta), shipping included in the receipt, skipping zero lines, and a UKTZED code per product plus a default one.

The KeyCRM source

Since version 0.5.0 the plugin fiscalises more than WooCommerce orders: it pulls paid orders from KeyCRM (an aggregator for Rozetka, Prom, Instagram and your own sites) and issues receipts for them through the same PRRO services. The menu is “Register → KeyCRM orders”: API key, polling interval, trigger, a run log, and an optional write-back of the receipt link into the KeyCRM order. Each order is fiscalised exactly once.

Offline sales from a Checkbox register → website stock (Pro)

A shop with a counter and a website sells the same shelf twice. The jacket was rung up at the till an hour ago, yet the website still shows it in stock — and the owner finds out once an online customer has already paid. Since 1.2.0 Pro closes that gap: every fiscalised receipt on the Checkbox register in the shop takes the same product off the WooCommerce stock, and a return receipt puts it back.

1. In Checkbox the product code equals the SKU of the product or variation on the website. If it differs, the plugin looks the barcode up — as a SKU and as a GTIN/EAN.
2. On the “Register → Offline sales” screen enter the cashier login and password and the licence key of the shop register (or leave them empty if it is the same register as on the Checkbox tab) and press “Connect the webhook”. The plugin registers the site address in Checkbox itself.
3. From then on Checkbox sends every receipt to the site. The plugin checks the signature with the key Checkbox issued, takes only fiscalised sales and returns, and changes the stock.

Receipts the website issued for its own online orders are skipped — WooCommerce has already reduced stock for them. Checkbox retries deliveries for hours, but the same receipt never changes anything twice, even when copies arrive at the same moment. A product that was not found, or one without stock tracking, shows up in the log as its own line — so you know exactly which code to fix in the register.

What is under the hood

• API keys and passwords are encrypted in the database — sodium_crypto_secretbox, with an HMAC stream cipher fallback when the libsodium extension is unavailable. Secrets are never printed back into form HTML.
• An adapter architecture: a shared provider interface plus a separate adapter for each PRRO service, and a primary → fallback chain.
• Duplicate protection — the fiscal number is checked against the database, retrying failed receipts never creates a second one; coupons are handled so that sum(line items) matches the total.
• The customer’s phone number is normalised to E.164 (+380…) before being sent to the PRRO.
• The catcodeprro_after_fiscalize hook — for your own integrations after a successful receipt.

How to install it

1. Install it from the WordPress.org directory, or upload it under “Plugins → Add New → Upload Plugin”, and activate.
2. Go to “Cash register → Settings” → the Vchasno.Kasa tab: enter the API key and the PRRO fiscal number from your Vchasno dashboard.
3. Press “Save and test connection” — a message confirms that the connection to Vchasno.Kasa works.
4. On the service tab set the role to “Primary register”, then on the “Receipts” tab switch on “Automatic receipts”.
5. Test it on a one-kopiyka order through “Register → Test” → “Issue receipt”.
6. A “success” row with a real fiscal number appears under “Register → Receipts” — you are done.