Overview

Warehouse 3PL is a third-party logistics (3PL) warehouse management system built as a custom Frappe app on top of ERPNext. It extends ERPNext's Stock module with a full set of 3PL-specific doctypes, workflows, and automation to manage multi-client warehouse operations from a single platform.

What is a 3PL?

A third-party logistics (3PL) provider stores and fulfills inventory on behalf of multiple clients (brands, manufacturers, e-commerce sellers). The warehouse operator:

• Receives goods from clients' suppliers
• Stores the goods in a shared physical facility
• Picks, packs, and ships orders on behalf of clients
• Bills clients for each service activity performed

The key challenge is that the goods belong to the clients, not the warehouse operator. The operator must track inventory precisely per client, isolate data between clients, and bill every touchpoint accurately.

System Architecture

warehouse_3pl/                    ← Custom Frappe app
├── warehouse_3pl/
│   ├── doctype/                  ← 24 custom doctypes
│   │   ├── warehouse_job_record/ ← Central job tracking (Enhanced Desk UI)
│   │   ├── asn/                  ← Advance Shipment Notice
│   │   ├── receiving/            ← Receiving (GRN)
│   │   ├── putaway_task/         ← Directed putaway
│   │   ├── client_order/         ← Outbound sales orders
│   │   ├── wave/                 ← Wave picking batches
│   │   ├── pick_task/            ← Pick instructions
│   │   ├── pack_task/            ← Pack instructions
│   │   ├── billing_transaction/  ← Activity-based billing log
│   │   ├── rate_card/            ← Per-client pricing
│   │   ├── inventory_policy/     ← Rule engine config
│   │   ├── warehouse_location/   ← Bin master
│   │   └── client_item/          ← Client SKU mapping
│   └── hooks.py                  ← ERPNext integration hooks
└── ...

The app sits on top of the standard ERPNext stack:

Zero-Value Accounting

One of the foundational design decisions is zero-value stock accounting.

When goods are received into the warehouse, they are posted to stock at ₹0 / $0 value. This is because:

1. The goods belong to the client, not the warehouse operator
2. The operator has no cost basis in the inventory
3. The operator earns revenue through service fees (receiving, storage, pick, pack, ship) — not by buying and reselling goods

INFO

All Stock Entries created by the system use valuation_rate = 0. ERPNext's standard accounting entries still fire, but the balance sheet impact is zero. The operator's P&L is driven entirely by Billing Transactions.

Clients can optionally supply their own item valuations for insurance or reporting purposes, but this does not affect the operator's books.

Key Modules

Module	Purpose	Primary Doctypes
Job Management	Central tracking hub for engagements	Warehouse Job Record
Inbound	Receive goods from suppliers	ASN, Receiving, Putaway Task
Outbound	Fulfill client orders	Client Order, Wave, Pick Task, Pack Task
Billing	Activity-based charge logging	Billing Transaction, Rate Card
Masters	Configuration and setup	Inventory Policy, Warehouse Location, Client Item
Stock (ERPNext)	Inventory ledger	Stock Entry, Stock Ledger Entry, Batch

System Architecture

Document Flow

Inbound

Outbound

Billing

Custom Doctypes

The app defines 24 custom doctypes:

Doctype	Category	Purpose
Warehouse Job Record	Job Management	Central umbrella document — links all activities for a client engagement
Job Storage Info	Job Management	Child table — storage details within a job
Job Vehicle Info	Job Management	Child table — vehicle/container tracking
Job Operational Info	Job Management	Child table — operational log entries
Job Stock Movement	Job Management	Child table — stock in/out tracking
Job Voucher	Job Management	Child table — linked financial vouchers
ASN	Inbound	Advance Shipment Notice — pre-alerts expected receipts
ASN Item	Inbound	Line items within an ASN
Receiving	Inbound	Goods Receipt Note — records actual receipt
Receiving Item	Inbound	Line items within a Receiving
Putaway Task	Inbound	Directed bin assignment for received stock
Client Order	Outbound	Client's outbound fulfillment request
Client Order Item	Outbound	Line items within a Client Order
Wave	Outbound	Batches multiple Client Orders for picking
Wave Order	Outbound	Links Wave to Client Orders
Pick Task	Outbound	Per-bin pick instruction for warehouse operators
Pack Task	Outbound	Packing instruction after picking is complete
Billing Transaction	Billing	Single activity charge record
Rate Card	Billing	Per-client pricing schedule
Rate Card Item	Billing	Individual rates within a Rate Card
Inventory Policy	Config	Rule engine settings per client/zone/item group
Warehouse Location	Config	Physical bin master (Zone/Aisle/Rack/Level/Bin)
Client Item	Config	Maps client SKUs to internal ERPNext items
Warehouse Zone	Config	Zone definitions with temperature and type
Stock Balance	Reporting	Denormalized view of current stock per client/item/location

ERPNext Extensions

The app adds custom fields to standard ERPNext doctypes:

Doctype	Custom Fields Added
Customer	is_3pl_client (checkbox), client_code (short ID), default_rate_card (link)
Warehouse	zone_type (Ambient/Cold/Frozen/Hazmat), location_type (Bulk/Rack/Floor), 3pl_managed (checkbox)
Item	temperature_zone, velocity_class (A/B/C), lot_tracked (checkbox), client_item_id
Batch	client (link to Customer), expiry_date (for FEFO), po_number
Stock Entry	3pl_reference_doctype, 3pl_reference_name, client (for filtering)
Delivery Note	client_order (link), wave (link), billing_logged (checkbox)

Tech Stack

Component	Version / Detail
Frappe Framework	v15 (Python-based web framework)
ERPNext	v15 (ERP application layer)
Python	3.10+
Database	MariaDB 10.6+
Cache / Queue	Redis 6+
Frontend	Vue 3 + Frappe UI (standard ERPNext desk)
API	REST (Frappe standard) + custom whitelisted methods

TIP

The system runs on a standard Frappe bench. See frappe.io/bench for installation docs. No Docker or custom infrastructure is required.