Multi PRRO Connector — fiscal receipts for OpenCart 2.3, 3.x & 4.x

Multi PRRO Connector for OpenCart is a fiscalisation module for OpenCart 2.3, 3.x and 4.x that connects your shop to Ukrainian software cash registers (PRRO) and issues a fiscal receipt automatically when an order moves into a chosen status (for example “Processing” after an online payment). Receipts, register shifts, Z-reports and customer notifications all live in the OpenCart admin — no copying data by hand into the register’s own dashboard.

Registers supported

• Vchasno.Kasa — sale and refund receipts, opening and closing a shift with a Z-report, key validation.
• Checkbox — sale and refund receipts, shifts, key validation.

A primary register plus a backup one: if the primary is unavailable, the receipt automatically goes through the fallback — an order will not be left unfiscalised because one service had an outage.

How it works, step by step

1. The customer pays — by card online or cash on delivery; the module works out from your list of payment methods what to fiscalise as cash and what as card.
2. The order moves into the trigger status (for example “Processing” after the gateway callback).
3. The module builds the receipt — line items, shipping (optionally), UKTZED codes, skipping zero lines — and sends it to the primary register; if that stays silent, the backup takes over.
4. The fiscal number comes back into the order and is written to the receipt log in the admin.
5. The customer receives the receipt by email and, optionally, by SMS through TurboSMS.
6. When an order is refunded into the refund status, the module issues a refund receipt.

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

A shop that sells both at a counter and online can easily sell the same item twice: it was rung up at the till, yet OpenCart still shows it in stock. Since 1.2.0 Pro closes that gap: every fiscalised sale receipt on the Checkbox register in the shop reduces the quantity of the same product in OpenCart, and a return receipt adds it back. It works in all three builds — OpenCart 4.x, 3.x and 2.3.

1. Give the product in Checkbox the same code as the SKU or model of the product on the website. If the code differs, the module looks the barcode up among EAN, UPC, JAN, ISBN, SKU and model.
2. On the module page press “Offline sales”, enter the cashier login and password and the licence key of the shop register (or leave them empty to use the register from the Checkbox tab) and press “Connect the webhook”. The module registers the storefront address in Checkbox itself.
3. After every receipt Checkbox calls the site. The module checks the signature with the key Checkbox issued and changes the quantity of the matched product.

Receipts the module issued for online orders are skipped — OpenCart already reduced stock at checkout. A repeated or parallel delivery of the same receipt changes nothing a second time. If several products share a code, the line is skipped so the wrong stock is not reduced; a product with “Subtract Stock” turned off is left alone. All of this shows up in the “Receipts received” log, one line per item.

What it costs

2,490 UAH — a one-off purchase. The licence is perpetual: you pay once, and updates and technical support are included in the price. One key covers two sites: your store and a staging copy.

Moving the shop to another domain? Deactivate the licence on the old one and activate it on the new one yourself from your account.

What is under the hood

• API keys and passwords are encrypted in the database with sodium_crypto_secretbox, or with an HMAC stream cipher when the libsodium extension is missing (typical for OpenCart 2.3 on PHP 7.0); a value encrypted in the admin is readable in both the catalog and the cron context.
• An adapter architecture: a shared provider interface, a register registry and a primary → backup chain.
• Shift control: manual buttons, auto-opening on the first sale of the day, and a schedule through the system cron — an exact HH:MM, not “once an hour” from the OpenCart scheduler.
• Logs in the admin: receipts in one place, shifts and Z-reports in another — you can see what was issued and when without logging into the register’s dashboard.

How to install it

1. Upload prro_connector.ocmod.zip through “Extensions → Installer”. For OpenCart 3.0.x use the prro_connector-oc3.ocmod.zip build, for 2.3 use cc_prro-oc2.ocmod.zip.
2. OpenCart 2.3: the stock installer in that version copies files over FTP only, so the contents of the upload/ folder from the archive go into the shop root manually, and then it is “Extensions → Modules → Install”.
3. Enable the module under “Extensions → Modules” and open its settings.
4. On the register tab, enter the API key and the PRRO fiscal number from your Vchasno or Checkbox dashboard and press “Test connection”.
5. In the general settings, pick the trigger status, the primary/backup register and the payment methods that count as cash.
6. Issue a test receipt on a one-kopiyka order and check the receipt log — a row with a fiscal number should appear.