Inventory Module

Overview

The Inventory module provides comprehensive stock management across multiple warehouses. It automatically tracks all inventory movements, maintains stock levels, and provides detailed audit trails for compliance and analysis.

Multi-Warehouse

Manage stock across multiple locations

Auto Adjustments

Automatic updates from sales and purchases

Audit Trail

Complete movement history

Core Components

Inventory Stock

Tracks the current quantity of each product in each warehouse.

app/Models/Inventory/InventoryStock.php

class InventoryStock extends Model
{
    protected $fillable = [
        'warehouse_id',
        'product_id',
        'quantity',
        'min_stock'
    ];

    public function warehouse(): BelongsTo {
        return $this->belongsTo(Warehouse::class);
    }

    public function product(): BelongsTo {
        return $this->belongsTo(Product::class);
    }
}

Key Fields:

warehouse_id - The warehouse location
product_id - The product being tracked
quantity - Current stock level
min_stock - Minimum threshold for low stock alerts

Inventory Movements

Records every change in inventory with complete audit information.

app/Models/Inventory/InventoryMovement.php

const TYPE_INPUT      = 'input';       // Compras, Producción
const TYPE_OUTPUT     = 'output';      // Ventas, Consumo
const TYPE_ADJUSTMENT = 'adjustment';  // Correcciones, Mermas
const TYPE_TRANSFER   = 'transfer';    // Entre almacenes

protected $fillable = [
    'warehouse_id',
    'product_id',
    'quantity',
    'type',
    'unit_cost',
    'description',
    'reference_type',  // Polymorphic: Sale, Purchase, etc.
    'reference_id',
];

Movement Types

Input
Output
Adjustment
Transfer

Input movements increase stock levels. Common scenarios:

Purchases from suppliers
Production of manufactured goods
Returns from customers
Initial stock setup

$this->inventoryService->register([
    'warehouse_id' => $warehouseId,
    'product_id'   => $productId,
    'quantity'     => 100,
    'type'         => InventoryMovement::TYPE_INPUT,
    'unit_cost'    => 50.00,
    'description'  => 'Purchase PO-2024-001',
]);

Accounting Entry:

Debit:  Inventory (1.2.01)        $5,000
Credit: Accounts Payable (2.1.01) $5,000

Output movements decrease stock levels. Common scenarios:

Sales to customers
Consumption for production
Damaged goods write-off

$this->inventoryService->register([
    'warehouse_id'   => $warehouseId,
    'product_id'     => $productId,
    'quantity'       => 10,
    'type'           => InventoryMovement::TYPE_OUTPUT,
    'description'    => 'Sale FAC-2024-001',
    'reference_type' => Sale::class,
    'reference_id'   => $saleId,
]);

Accounting Entry:

Debit:  Cost of Goods Sold (5.1)   $500
Credit: Inventory (1.2.01)         $500

Adjustment movements correct stock discrepancies. Common scenarios:

Physical count reconciliation
Damage or spoilage
Theft or loss
Reversals from canceled sales

$this->inventoryService->register([
    'warehouse_id' => $warehouseId,
    'product_id'   => $productId,
    'quantity'     => 5,  // Positive = increase, Negative = decrease
    'type'         => InventoryMovement::TYPE_ADJUSTMENT,
    'description'  => 'Physical count adjustment',
]);

Accounting Entry (Loss):

Debit:  Inventory Variance (5.3)   $250
Credit: Inventory (1.2.01)         $250

Transfer movements move stock between warehouses. This creates two movements:

Output from source warehouse
Input to destination warehouse

// This is handled automatically by the service
$this->inventoryService->register([
    'warehouse_id'          => $sourceWarehouseId,
    'product_id'            => $productId,
    'quantity'              => 20,
    'type'                  => InventoryMovement::TYPE_TRANSFER,
    'destination_warehouse' => $destWarehouseId,
    'description'           => 'Transfer to Main Warehouse',
]);

No accounting entry - just moves stock between locations.

Inventory Service

The InventoryMovementService handles all stock operations with automatic accounting integration.

Register Movement

app/Services/Inventory/InventoryMovementService.php

public function register(array $data): InventoryMovement
{
    return DB::transaction(function () use ($data) {
        $movement = InventoryMovement::create($data);

        // Update stock level
        $stock = InventoryStock::firstOrCreate(
            [
                'warehouse_id' => $data['warehouse_id'],
                'product_id'   => $data['product_id'],
            ],
            ['quantity' => 0]
        );

        // Adjust quantity based on movement type
        if ($data['type'] === InventoryMovement::TYPE_OUTPUT) {
            $stock->decrement('quantity', $data['quantity']);
        } else {
            $stock->increment('quantity', $data['quantity']);
        }

        // Generate accounting entry if applicable
        if ($this->shouldGenerateAccounting($data['type'])) {
            $this->generateAccountingEntry($movement);
        }

        return $movement;
    });
}

Stock Validation

Before creating output movements, the system validates stock availability:

$currentStock = InventoryStock::where('warehouse_id', $warehouseId)
    ->where('product_id', $productId)
    ->value('quantity') ?? 0;

if ($currentStock < $requestedQuantity) {
    throw new \Exception(
        "Stock insuficiente. Disponible: {$currentStock}"
    );
}

Output movements will fail if insufficient stock is available. Use adjustments for corrections.

Warehouses

The system supports multiple warehouse locations:

app/Models/Inventory/Warehouse.php

protected $fillable = [
    'name',
    'code',
    'location',
    'is_active',
];

public function stocks(): HasMany {
    return $this->hasMany(InventoryStock::class);
}

public function movements(): HasMany {
    return $this->hasMany(InventoryMovement::class);
}

Common Warehouse Setups

Single Location

Simple businesses with one warehouse:

Main Warehouse - All products stored here

Multi-Location

Businesses with multiple sales locations:

Main Warehouse - Primary storage
Store 1 - Retail location
Store 2 - Retail location

Distribution

Distribution businesses:

Central - Main distribution center
North - Regional warehouse
South - Regional warehouse
Transit - In-transit goods

Stock Queries

Current Stock Levels

// Stock for a specific product in a warehouse
$stock = InventoryStock::where('warehouse_id', $warehouseId)
    ->where('product_id', $productId)
    ->first();

echo "Current quantity: {$stock->quantity}";

Low Stock Alerts

// Products below minimum stock level
$lowStock = InventoryStock::whereColumn('quantity', '<', 'min_stock')
    ->with('product', 'warehouse')
    ->get();

Stock Value

// Total inventory value by warehouse
$value = InventoryStock::where('warehouse_id', $warehouseId)
    ->join('products', 'products.id', '=', 'inventory_stocks.product_id')
    ->selectRaw('SUM(inventory_stocks.quantity * products.cost) as total_value')
    ->value('total_value');

Movement History

// All movements for a product
$movements = InventoryMovement::where('product_id', $productId)
    ->with('warehouse')
    ->latest()
    ->get();

// Movements within date range
$movements = InventoryMovement::whereBetween('created_at', [$startDate, $endDate])
    ->where('type', InventoryMovement::TYPE_OUTPUT)
    ->get();

Reporting

Stock Report

View current stock levels across all warehouses:

$stockReport = InventoryStock::with(['product', 'warehouse'])
    ->where('quantity', '>', 0)
    ->get()
    ->groupBy('warehouse.name');

Movement Report

Track all inventory activity:

$movements = InventoryMovement::with(['product', 'warehouse'])
    ->whereBetween('created_at', [$startDate, $endDate])
    ->latest()
    ->get();

Excel Export

app/Http/Controllers/Inventory/InventoryStockController.php

public function export(Request $request)
{
    $query = (new InventoryFilters($request))
        ->apply(InventoryStock::query());

    return Excel::download(new InventoryStockExport($query), 'stock.xlsx');
}

Integration Points

Sales Module

When a sale is created, inventory is automatically reduced:

app/Services/Sales/SalesServices/SaleService.php

foreach ($data['items'] as $item) {
    $this->inventoryService->register([
        'warehouse_id'   => $data['warehouse_id'],
        'product_id'     => $item['product_id'],
        'quantity'       => $item['quantity'],
        'type'           => InventoryMovement::TYPE_OUTPUT,
        'reference_type' => Sale::class,
        'reference_id'   => $sale->id,
    ]);
}

Accounting Module

Inventory movements generate journal entries for proper cost tracking:

Inputs increase inventory asset and create payable/expense
Outputs recognize cost of goods sold
Adjustments account for variance

Best Practices

Use Polymorphic References

Always link movements to their source document:

'reference_type' => Sale::class,
'reference_id'   => $sale->id,

This provides complete audit trails and enables reversals.

Set Minimum Stock Levels

Configure min_stock for each product-warehouse combination:

InventoryStock::updateOrCreate(
    ['product_id' => $productId, 'warehouse_id' => $warehouseId],
    ['min_stock' => 10]
);

Regular Physical Counts

Perform periodic physical counts and use adjustments to reconcile:

$systemQty = $stock->quantity;
$physicalQty = 95;  // From count
$variance = $physicalQty - $systemQty;

if ($variance != 0) {
    $this->inventoryService->register([
        'type' => InventoryMovement::TYPE_ADJUSTMENT,
        'quantity' => abs($variance),
        'description' => 'Physical count adjustment',
    ]);
}

Monitor Negative Stock

Prevent negative stock situations:

if ($stock->quantity < $requestedQty) {
    throw new \Exception('Insufficient stock');
}

Sales Module

How sales integrate with inventory

Products Module

Product configuration

Accounting

Financial integration

Inventory Service API

Service implementation details

Get Started

Core Concepts

Modules

Features

Development

Overview

Multi-Warehouse

Auto Adjustments

Audit Trail

Core Components

Inventory Stock

Inventory Movements

Movement Types

Inventory Service

Register Movement

Stock Validation

Warehouses

Common Warehouse Setups

Stock Queries

Current Stock Levels

Low Stock Alerts

Stock Value

Movement History

Reporting

Stock Report

Movement Report

Excel Export

Integration Points

Sales Module

Accounting Module

Best Practices

Sales Module

Products Module

Accounting

Inventory Service API

Build docs developers (and LLMs) love

Get Started

Core Concepts

Modules

Features

Development

​Overview

Multi-Warehouse

Auto Adjustments

Audit Trail

​Core Components

​Inventory Stock

​Inventory Movements

​Movement Types

​Inventory Service

​Register Movement

​Stock Validation

​Warehouses

​Common Warehouse Setups

​Stock Queries

​Current Stock Levels

​Low Stock Alerts

​Stock Value

​Movement History

​Reporting

​Stock Report

​Movement Report

​Excel Export

​Integration Points

​Sales Module

​Accounting Module

​Best Practices

​Related Documentation

Sales Module

Products Module

Accounting

Inventory Service API

Build docs developers (and LLMs) love

Overview

Core Components

Inventory Stock

Inventory Movements

Movement Types

Inventory Service

Register Movement

Stock Validation

Warehouses

Common Warehouse Setups

Stock Queries

Current Stock Levels

Low Stock Alerts

Stock Value

Movement History

Reporting

Stock Report

Movement Report

Excel Export

Integration Points

Sales Module

Accounting Module

Best Practices

Related Documentation