BIR E-invoice

Originally initiated as an e-commerce platform (Haru-main), the codebase evolved significantly into BIR E-invoice. While the underlying e-commerce catalog modules were retained, the system was re-architected on Laravel 11.56 with specialized compliance domains: an automated Shopee Open API v2 adapter, a Philippine 12% VAT tax calculation engine, asynchronous PDF generator jobs, and raw ESC/POS thermal printer hardware streaming.

// Strict pessimistic sequence locking in Laravel 11
return DB::transaction(function () use ($order, $taxSnapshot) {
    // 1. Acquire exclusive lock on the specific active fiscal series
    $sequence = InvoiceSequence::where('series_code', 'BIR-2026')
        ->where('is_active', true)
        ->lockForUpdate()
        ->firstOrFail();

    // 2. Compute the deterministic next sequential number
    $nextNumber = $sequence->current_number + 1;
    $sequence->update(['current_number' => $nextNumber]);

    // 3. Issue the immutable official invoice with cryptographic snapshot
    return Invoice::create([
        'invoice_number' => $sequence->prefix . str_pad($nextNumber, 8, '0', STR_PAD_LEFT),
        'order_id'       => $order->id,
        'gross_amount'   => $taxSnapshot['gross_total'],
        'vatable_sales'  => $taxSnapshot['vatable_sales'],
        'vat_amount'     => $taxSnapshot['vat_amount'],
        'snapshot_hash'  => hash('sha256', json_encode($taxSnapshot)),
        'issued_at'      => now(),
    ]);
});

Because tax rules or entity thresholds may adjust across fiscal years, past invoices cannot be retroactively recalculated. BIR E-invoice serializes the exact rule version, tax rates (12% VAT), and item classifications at the millisecond of issuance, sealing the record with an immutable SHA-256 fingerprint.