Automating Invoice Issuance in 1C-Bitrix: Turnkey Setup

Introduction – The Pain Point

Imagine a manager spending 30 minutes manually creating an invoice in Word, then losing it in email correspondence — and the client never pays on time. In B2B sales, this is critical: without an invoice, the accountant won't process the payment. We've seen dozens of projects where automating document flow shortened the deal cycle by 2-3 days. Setting up a proper invoicing system is the first step toward financial discipline.

We often encounter clients losing deals simply because the invoice wasn't issued on time or arrived in the wrong format. In B2B, without an invoice the deal stalls: the accountant needs a documented basis for payment. Configuring correct document flow is one of the first tasks when launching an online store on Bitrix. In our practice, we've automated this process for over 60 projects, saving clients an average of $1,500 per month in manual work.

Problems We Solve

• Manual generation: Managers spend hours creating invoices in Word or Excel, making errors in details. A custom solution reduces this time by 80%.
• Lost documents: Invoices get stuck in email threads, never reaching the accounting department. Automated sending eliminates this issue.
• Numbering conflicts: When multiple managers work in parallel, duplicate numbers appear, violating tax regulations. Our custom numbering avoids duplicates.
• No online payment: Clients can't pay immediately via a link — the deal drags on. Adding a payment link speeds up payment by 2 days on average.

Consider: the standard Bitrix24 solution delivers 80% of functionality in 1 day, while a custom system gives 100% control but requires 3–5 days of development. A custom solution is 3 times more flexible than the standard one, especially if you work with dozens of legal entities and multiple currencies.

How We Issue Invoices in Bitrix24

Bitrix24 CRM has a built-in invoice module. A manager creates an invoice directly in CRM, links it to a deal, and sends it to the buyer via email. Payment is processed through the built-in acquiring (Tinkoff, Sberbank, YooKassa) or by bank details. To get started, you need:

• Configure the invoice template (company details, logo)
• Connect a payment system
• Set up automatic sending at a certain deal status

Basic setup takes half a day and costs from $500. If integration with 1C is needed, add another day ($800).

When a Custom Invoicing System Is Needed

On a regular website (not Bitrix24), there is no built-in invoice module. If you have an online store on the Bitrix "Small Business" or "Business" edition without CRM, you'll need to build a custom system based on the Sale module. This is justified when:

• Non-standard numbering is required (e.g., branch prefix)
• A custom PDF template with INN/KPP/bank account fields is needed
• Integration with external accounting (1C, MyWarehouse) is required

For storing custom invoice templates, we use infoblocks v2.0, and for flexible settings — HL-blocks. This allows quick adaptation to changes in legislation.

Why Correct Invoice Numbering Matters

Tax authorities and accounting require sequential numbering without gaps. In Bitrix24, an invoice gets a number automatically, but when exchanging with 1C via CommerceML, conflicts can arise. We implement reliable numbering through our own table:

CREATE TABLE b_invoices ( id SERIAL PRIMARY KEY, order_id INT REFERENCES b_sale_order(ID), invoice_number VARCHAR(32) UNIQUE NOT NULL, -- FS-{year}-00123 user_id INT, company_name VARCHAR(256), inn VARCHAR(12), kpp VARCHAR(9), legal_address TEXT, amount DECIMAL(10,2), currency CHAR(3) DEFAULT 'RUB', status VARCHAR(16) DEFAULT 'draft', -- draft|sent|paid|cancelled due_date DATE, paid_at TIMESTAMP, created_at TIMESTAMP DEFAULT NOW() ); 

function generateInvoicePdf(array $invoice, array $orderItems): string { $mpdf = new Mpdf\Mpdf(['mode' => 'utf-8', 'format' => 'A4']); $html = renderInvoiceTemplate($invoice, $orderItems); $mpdf->WriteHTML($html); $path = DOCUMENT_ROOT . '/upload/invoices/invoice_' . $invoice['id'] . '.pdf'; $mpdf->Output($path, 'F'); return $path; } 

function nextInvoiceNumber(): string { $db = Bitrix\Main\Application::getConnection(); $year = date('Y'); $last = $db->queryScalar(" SELECT MAX(CAST(SPLIT_PART(invoice_number, '-', 3) AS INT)) FROM b_invoices WHERE invoice_number LIKE 'FS-" . $year . "-%' "); $next = ((int)$last + 1); return sprintf('FS-%d-%05d', $year, $next); }