PDF invoices for OpenCart 4.x and 3.0.x, issued automatically when an order reaches the statuses you choose, numbered without gaps (formats with year, month, day and order id, digits, start number, yearly reset; OpenCart's own invoice number kept in step) and frozen at issue. Numbered credit notes for chosen quantities, shipping and fees, an extra amount or everything open, also automatic at refund and cancel statuses; packing slips. Three PDF styles with your logo and accent colour, A4 or US Letter, embedded fonts for Latin, Greek and Cyrillic, made on your own server. E-mail with the PDF attached, downloads in the customer account, overview, document list, bulk PDF, ZIP and CSV, invoices for older orders. Events only, no OCMOD.
Tested on 4.1.0.4 & 3.0.5.1Updated Nov 4, 2026Version 1.0.0Compatible with OpenCart 4.1.0.4, 3.0.5.1 No core file edits
Built forOpenCart
Invoices that look like your brand1 of 6
What it does
PDF invoices for OpenCart 4.x and 3.0.x, issued automatically when an order reaches the statuses you choose, numbered without gaps (formats with year, month, day and order id, digits, start number, yearly reset; OpenCart's own invoice number kept in step) and frozen at issue. Numbered credit notes for chosen quantities, shipping and fees, an extra amount or everything open, also automatic at refund and cancel statuses; packing slips. Three PDF styles with your logo and accent colour, A4 or US Letter, embedded fonts for Latin, Greek and Cyrillic, made on your own server. E-mail with the PDF attached, downloads in the customer account, overview, document list, bulk PDF, ZIP and CSV, invoices for older orders. Events only, no OCMOD.
Invoices your accountant will accept. OpenCart prints a plain HTML invoice with one simple counter and no credit notes. PDF Invoices & Credit Notes issues a real PDF invoice for every paid order, numbered without gaps, and corrects it with numbered credit notes.
Features
Automatic
Invoice issued when the order reaches the statuses you choose (checkout, payment callbacks, admin changes)
Credit note for everything still open when the order is refunded or cancelled
E-mail to the customer with the PDF attached and a download link; optional copy to your bookkeeping
Documents on the order page of the customer account
Numbers and content
Number formats with year, month, day and order id, digits, start number, yearly reset
Gapless and unique, also when payments arrive in the same second
OpenCart's own invoice number kept in step
Content frozen at issue: later edits never change an issued invoice
Credit notes and packing slips
Credit chosen quantities, shipping and fees or an extra amount on the order page, or everything open in one click
Discounts and taxes follow the invoice; never more than the open amount
Packing slips with product images and tick boxes
Design
Three styles: Modern, Classic, Minimal; your logo and accent colour; A4 or US Letter
Embedded fonts: Latin, Greek and Cyrillic names print correctly
Made on your own server: no external PDF service
Admin
Overview with this month's figures, documents list with search and filters
Bulk print as one PDF, ZIP of PDFs, CSV for your accountant
Invoices for existing orders in one step
Buyer VAT number and reverse-charge note with our EU VAT Number Validation
Events only, no OCMOD
One license for OpenCart 4 and 3, tested on 4.1.0.4 and 3.0.5.1
What you get
Download & installTwo installer packages (.ocmod.zip): one for OpenCart 4.0.2 – 4.1.x and one for 3.0.3 – 3.0.5. One license key covers both. Download it from My licenses right after payment.
12 months of updates & supportNew versions and help for 12 months (24 or 36 months at checkout). After that the extension keeps working; renew anytime at 50%.
License for your storeOne production domain with all its subdomains; staging and local development hosts are free. How licensing works
30-day refundFull refund within 30 days of your first purchase, no reason needed. Refund policy
Tested buildsOpenCart 4.1.0.4, 3.0.5.1. Tested on OpenCart 4.1.0.4 and OpenCart 3.0.5.1.
Documentation & supportFull guide (Installation, Configuration, Usage, FAQ) on this page. Tickets from your account, first reply within 1 business day.
Compatibility
PDF Invoices & Credit Notes works with OpenCart 4.1.0.4, 3.0.5.1.
We list the builds we install and test on. “Tested” means the test plan ran on that build; “Supported” means the build is inside the supported range.
Compatibility
Version
Range
Runs on
Status
OpenCart 4.1.0.x
4.1.0.0 – 4.1.0.4
PHP 8.1 – 8.3
Tested on 4.1.0.4
OpenCart 4.0.2.x
4.0.2.0 – 4.0.2.3
PHP 8.0 – 8.2
Supported
OpenCart 3.0.x
3.0.3.8 – 3.0.5.x
PHP 7.4 – 8.1
Tested on 3.0.5.1
1.0.0
Nov 4, 2026
Latest
First release: PDF invoices issued automatically at the order statuses you choose, numbered without gaps (number formats with year, month, day, order id, digits, start number, yearly reset) and frozen at issue; OpenCart's own invoice number kept in step; numbered credit notes (chosen quantities, shipping and fees, an extra amount, or everything still open) and automatic credit notes at refund or cancel statuses; packing slips; three PDF styles (Modern, Classic, Minimal) with your logo, accent colour, A4 or US Letter, product images, model, SKU and tax column; Unicode fonts embedded (Latin, Greek, Cyrillic), no external PDF service; e-mail with the PDF attached and a signed download link; documents on the customer's order page; overview, document list with search, bulk PDF, ZIP and CSV, invoicing of existing orders; documents panel on the OpenCart order page; buyer VAT number and reverse-charge note from our EU VAT Number Validation.
How do I install the extension?
Upload. Extensions > Installer: upload the .ocmod.zip for your OpenCart version (4.x or 3.0.x). Both packages come with every license.
Install and enable. Extensions > Extensions > Modules: install, open the settings and switch it on. Events register themselves; nothing is patched.
Enter the license key. Paste the key from My licenses. Subdomains, staging and local hosts are included; you have 14 days to do it.
OpenCart 4.1.0.4, 3.0.5.1. Tested on OpenCart 4.1.0.4 and OpenCart 3.0.5.1. The Compatibility tab lists every version range.
Do the extensions change core files?
No. They work through OpenCart events and standard extension types (modules, order totals, themes). No core file edits, no OCMOD patches, no theme template edits, so OpenCart updates and other extensions keep working.
Do I get packages for OpenCart 4 and OpenCart 3?
Yes. Every download has a package for OpenCart 4.0.2 to 4.1.x and one for OpenCart 3.0.3 to 3.0.5, and the license key works with both. Moving from OpenCart 3 to 4 later costs nothing.
What does the license cover?
One production store domain with every subdomain (www, shop., staging.), plus local development hosts such as localhost, *.local and *.test. A store on another domain needs its own license; a second-store license is 40% off. You have 14 days after installing to enter the key. 12 months of updates and support are included; after that the extension keeps working and renewals are 50% off. How licensing works
Can I get a refund?
Yes. Ask for a full refund within 30 days of your first purchase, no reason needed: open a ticket or write to [email protected] with your order number. The money goes back to the card or bank account you paid with within 5 business days of approval. Refund policy
How do I get help?
Open a ticket from your account, so your license details are attached. We answer Monday to Friday: bug reports within 1 business day, how-to questions within 2. Support policy. Not a customer yet? Ask a pre-sales question.
PDF Invoices & Credit Notes gives every OpenCart order a proper invoice: a PDF with your logo and company details, numbered without gaps, issued automatically when the order is paid, e-mailed to the customer and available in their account. Corrections are made with numbered credit notes, as accountants and tax offices expect.
Invoices at the right moment. Choose the order statuses that issue the invoice (for example Processing and Complete). Checkouts, payment callbacks and status changes in the admin all count.
Numbers without gaps. Formats like INV-{YYYY}-{N} with year, month, day and order id placeholders, the number of digits, a start number and a yearly reset. Numbers come from a locked counter, so two payments in the same second never share or skip a number. OpenCart's own invoice number on the order is kept in step.
Frozen content. Each document keeps the addresses, products, prices, taxes and company details it was issued with. Later edits to the order, the product or your settings never change an issued PDF.
Credit notes. Credit chosen quantities, shipping and fees or an extra amount on the order page, or everything still open in one click. Discounts and taxes follow the invoice in proportion, and a credit note can never exceed what is open. Orders that reach a refund or cancel status get their credit note automatically.
Packing slips with product images, quantities and a tick box for each line.
Designs that look like you. Three styles (Modern, Classic, Minimal), your store logo, an accent colour, A4 or US Letter, product images, model, SKU and a tax column. The fonts are embedded, so names and addresses in Latin, Greek and Cyrillic scripts print correctly. PDFs are made on your own server: no external service, no order data leaves your store.
Delivered to the customer. A short e-mail with the PDF attached and a download link, plus the documents on the order page of the customer account. Optional copy of every e-mail to your bookkeeping address.
For you and your accountant. Overview with this month's figures, a searchable document list, bulk print as one PDF, a ZIP of PDFs and a CSV export; invoices for orders placed before the installation in one step.
EU VAT ready. When our EU VAT Number Validation is installed, the buyer's checked VAT number and the reverse-charge note print on the invoice.
No OCMOD, no core file edits: events only. One licence covers OpenCart 4 and 3. Tested on OpenCart 4.1.0.4 and 3.0.5.1 with the default themes; other 4.0.2.x to 4.1.x and 3.0.3.8 to 3.0.5.x versions are expected to work but are not tested.
Installation
Requirements
OpenCart 4.0.2.0 to 4.1.x, or 3.0.3.8 to 3.0.5.x
PHP 7.4 or newer with mbstring and zlib (OpenCart needs them anyway); GD for logos and product images that are not JPEG; ZipArchive for ZIP downloads (without it the bulk download is one PDF)
Working store e-mail (System > Settings > Mail) if customers should get their PDFs by e-mail
Install on OpenCart 4
Go to Extensions > Installer and upload kv_invoice_builder.ocmod.zip.
Press the install button next to PDF Invoices & Credit Notes.
Go to Extensions > Extensions, choose Modules and install PDF Invoices & Credit Notes.
Install on OpenCart 3
Go to Extensions > Installer and upload kv_invoice_builder-oc3.ocmod.zip.
Go to Extensions > Modifications and press Refresh.
Go to Extensions > Extensions, choose Modules and install PDF Invoices & Credit Notes.
First steps
Open Sales > Invoices & credit notes > Settings.
Check the order statuses that issue invoices and credit notes. The installation picks your complete statuses plus Processing and Processed for invoices, and Canceled, Refunded, Reversed, Chargeback and Voided for credit notes.
Check your company details, the number format and the start number. To continue your current numbering, enter the next number as the start number.
Pick a style, save and press Preview PDF.
Optional: on the Overview tab, issue invoices for orders placed before the installation.
Updating
Upload the new package the same way. Documents, numbers and settings stay; tables and settings are brought up to date the next time you open the extension.
Removing
Uninstalling removes the extension's tables (issued documents and counters) and its settings. Download a ZIP and a CSV of your documents first (Documents > ZIP / CSV). Orders and the OpenCart invoice numbers written into them stay.
Configuration
Sales > Invoices & credit notes > Settings
Automation
Setting
Default
What it does
Status
On
Off: nothing is issued and customers cannot download documents; issued documents stay.
Issue the invoice at
Complete statuses, Processing, Processed
The first time an order reaches one of these statuses it gets its invoice.
Issue a credit note at
Canceled, Refunded, Reversed, Chargeback, Voided
An invoiced order that reaches one of these statuses gets a credit note for everything still open. A status cannot be in both lists.
E-mail to the customer
On
Sends the invoice or credit note PDF when it is issued, with a download link.
Copy of each e-mail to
empty
Your bookkeeping address; several separated by commas.
Customer account
On
Documents on the order page of the customer account.
Numbering
Setting
Default
What it does
Invoice number format
INV-{YYYY}-{N}
Placeholders: {N} running number (required, once), {YYYY}, {YY}, {MM}, {DD}, {ORDER}. Letters, digits and - _ / . #.
Credit note number format
CN-{YYYY}-{N}
Same placeholders; must differ from the invoice format.
Digits of {N}
5
5 gives 00042.
Start number
1
First number of a new series (a new year with the yearly reset).
Yearly reset
On
Numbers start again at the start number every calendar year.
OpenCart invoice number
On
Writes the number into the order, so OpenCart's invoice print, the order page and the customer's order page show the same number. Works with formats that end with {N}.
Your company on the documents
Company name, address, e-mail, phone, VAT / tax ID, registration number, payment terms (invoices), bank details (invoices), a note (every document) and the footer (every page; empty prints your company name and address). The installation fills in the store name, address, e-mail and phone.
Design
Setting
Default
What it does
Style
Modern
Modern (accent bands and cards), Classic (ruled boxes, grey table head), Minimal (thin accent lines).
Accent colour
#4f46e5
Title, table head and total of Modern; lines and total of Minimal.
Paper
A4
A4 or US Letter.
Logo
On
Prints the store logo from System > Settings > Image.
Product lines
Model on
Product images, model, SKU and a tax column.
Preview PDF shows the latest order with the saved settings; nothing is issued.
Licence (own-store edition)
Enter the key from your Kavio Labs account. Without a valid key, automatic invoicing, the e-mails and customer downloads stop after the 14-day trial; the admin pages, manual issuing and the PDFs of issued documents always work.
Usage
On the order page
Every order page in Sales > Orders shows an Invoices & credit notes panel at the top:
the invoice and credit notes of the order with PDF and E-mail buttons;
Issue invoice when the order has none yet (the number is final);
Packing slip: a PDF with the delivery address, the products, quantities and a tick box per line;
Credit note: enter the quantities to credit, tick shipping and fees, add an extra amount (with tax) and a reason, then Create credit note; or Credit everything open.
A credit note documents the correction; it does not refund money. Refund the payment as usual with your payment provider.
Overview
This month's invoiced amount, invoices, credit notes, orders in an invoicing status without an invoice (with Invoice them now: up to 200 at a time, oldest first, without e-mails), the last six months and the latest documents.
Documents
Search by number, order id, customer or e-mail, and filter by type and date. Print all (PDF) puts the documents of the filter into one PDF, ZIP gives one PDF per document and CSV a list for your accountant (net, tax and total in the order currency). Up to 500 documents per download.
For customers
When a document is issued, the customer gets a short e-mail with the PDF attached and a download link that works without signing in. Signed-in customers find their documents on the order page of their account (Account > Order History > View).
Amounts and currencies
Documents print in the currency of the order with the exchange rate of the order, like OpenCart's own invoice. The totals are OpenCart's order totals (sub-total, discounts, shipping, taxes, total) as they were when the document was issued.
FAQ
Can I continue my current invoice numbers?
Yes. Enter the next number as the start number and use the same format, for example INV-{YYYY}-{N} with 5 digits. Numbers are given strictly one after the other.
Why can I not edit an issued invoice?
An issued invoice is a legal document. It keeps the content it was issued with; corrections are made with credit notes. If an order changes before it is invoiced, the invoice shows the new content.
What happens when I edit an order after invoicing?
The invoice stays as issued. Credit the difference with a credit note.
Does it use an external PDF service?
No. The PDFs are made on your own server by the extension itself, with embedded fonts. No order data leaves your store.
Which languages and scripts print?
The document labels are in English; names, addresses and products in Latin, Greek and Cyrillic scripts print correctly. Other scripts (for example Chinese or Arabic) are not supported: their characters print as placeholder symbols.
Does it replace OpenCart's own invoice print?
No, OpenCart's HTML print stays available. With OpenCart invoice number switched on, both show the same number.
Does it work with my payment extension?
Yes. Invoices follow the order status, whichever extension sets it, including payment callbacks.
What about EU VAT and reverse charge?
Enter your VAT ID in the settings. With our EU VAT Number Validation installed, the buyer's checked VAT number and the reverse-charge note print automatically.
Server-side tracking for OpenCart 4.x and 3.0.x: purchases, refunds, add to cart, checkout, product views and leads go from your server to the free official GA4 Measurement Protocol, Meta Conversions API and TikTok Events API, deduplicated with the browser pixels through shared event ids. Consent-aware, SHA-256 hashed customer data, order status mapping, queue with retries, test mode and an event log. No paid relay, events only, no OCMOD.
The department store theme for OpenCart 4.x and 3.0.x: colour-coded departments, a department list beside the hero slider with two side promos, a big search with a department selector, tabbed product blocks, a 2 + 1 + 2 offer grid, deals of the day with real countdowns, a department showcase, a promotions band and a three-column product page with a sticky buy box. Four styles (Meridian, Harbor, Citrus, Night) and your own colours on top. Events only, no core changes.
Stop AI crawlers, scrapers, vulnerability scanners and unwanted countries before OpenCart 4.x or 3.0.x builds a page. Googlebot and Bingbot are verified by DNS and always allowed; 50+ bots get one switch each; country rules use free GeoIP databases and can close only the checkout; IP and network lists, rate limits, honeypots and the cart flood fix; a one-second challenge instead of a captcha; learning mode, dashboard, log, IP tester and Cloudflare export. No core changes, no OCMOD.
