EDI Conversion for 3PL Warehouses: Processing 850 POs & 856 ASNs Without Full EDI Software

You operate a 3PL (third-party logistics) warehouse. Your clients sell to Walmart, Target, Amazon, Home Depot. They receive EDI 850 purchase orders from retailers. They send you the EDI files (or you retrieve them from the retailer's portal). You need to:

• Extract order details from EDI 850 PO: customer address, SKUs, quantities, delivery dates
• Import to your WMS (Warehouse Management System): ShipStation, ShipHero, 3PL Central, NetSuite, custom WMS
• Pick, pack, and ship the order
• Generate EDI 856 ASN with tracking numbers and send back to your client or retailer

The challenge: Full EDI integration costs $15,000-$75,000 per client (custom WMS mapping, VAN/AS2 setup, testing). With 5-10 clients, that's $75,000-$750,000 in integration fees. Plus $500-$2,000/month per client in ongoing EDI software costs.

The solution for smaller 3PLs: Convert EDI to CSV with PlainEDI ($99/month unlimited files). Import CSV to your WMS manually or via CSV import tools. Generate ASN data from your WMS, submit via retailer portals or convert back to EDI 856 format.

This guide covers the complete 3PL EDI workflow, when you need full EDI integration vs simple CSV conversion, WMS integration strategies, and cost-benefit analysis for 3PL operators managing multiple clients.

Understanding the 3PL EDI Document Flow

The typical 3PL EDI workflow involves these standard documents:

Inbound: EDI 850 Purchase Order (Most Common)

Source: Your client's customer (Walmart, Target, Amazon) sends 850 PO to your client. Your client forwards to you or grants you access to download from retailer portal.

Contains:

• PO number, PO date (BEG segment)
• Customer ship-to name, address, city, state, ZIP (N1/N3/N4 segments)
• Line items: SKU/UPC, description, quantity, unit price (PO1 segment)
• Delivery date / Must Arrive By Date (DTM segment)
• Special instructions: gift message, packing requirements, retailer compliance notes

Your task: Import 850 data into your WMS to create pick list and shipping label.

Inbound: EDI 940 Warehouse Shipping Order (Less Common)

Source: Your client sends 940 directly to you (not from retailer).

Contains: Similar to 850 but formatted specifically for 3PL/warehouse operations (includes warehouse location codes, special handling instructions).

When used: Clients with their own WMS/ERP that generate 940 for 3PL fulfillment instead of forwarding retail 850 POs.

Outbound: EDI 856 Advance Ship Notice (Critical)

Recipient: Your client or directly to the retailer (Walmart/Target/Amazon).

Contains:

• Original PO number reference
• Shipment tracking number, carrier name (UPS/FedEx/USPS)
• Ship date, estimated delivery date
• Items shipped: SKU, quantity, carton count
• SSCC (Serial Shipping Container Code) for pallet/carton tracking

Your task: Generate 856 ASN from your WMS shipping data. Either send to client (they submit to retailer) or submit directly to retailer portal.

Why critical: Late or missing ASNs trigger retailer penalties. Walmart charges late ASN fees. Amazon requires 856 ASN 4 hours before delivery. Target charges $0.75/carton for missing ASNs (effective May 4, 2025).

Outbound: EDI 943 Warehouse Stock Transfer Receipt Advice (Inventory)

Recipient: Your client (for inventory tracking).

Contains: Notification that you've received inventory from your client. Includes SKU, quantity received, storage location in your warehouse.

When used: Clients with tight inventory management need 943 to update their systems when you receive their stock.

Outbound: EDI 810 Invoice (Billing)

Recipient: Your client (for your warehouse services billing).

Contains: Your 3PL service charges: receiving fees, storage fees, pick/pack fees, shipping costs.

Note: This is your invoice to your client for warehouse services, not the retailer invoice (your client handles retailer invoicing separately).

3PL EDI to CSV Workflow (Without Full EDI Integration)

For 3PLs handling 10-100 orders/day per client, CSV conversion is often more cost-effective than full EDI integration. Here's the step-by-step process:

Step 1: Receive EDI 850 Purchase Order from Client

Method A: Client emails you .edi file

• Client downloads 850 PO from Walmart Retail Link / Target Partners Online / Amazon Vendor Central
• Client emails you the .edi file with subject "New Order - PO #123456"

Method B: You download from retailer portal (if client grants access)

• Client gives you login credentials to Walmart DSV Portal / Target Partners Online / Vendor Central
• You download 850 PO files daily

Method C: SFTP drop folder

• Client sets up SFTP server
• Client uploads .edi files to SFTP folder
• You download files via SFTP client

Step 2: Convert EDI 850 to CSV with PlainEDI

1. Upload .edi file to PlainEDI (drag & drop or browse)
2. PlainEDI parses EDI 850 and displays instant preview
3. CSV includes labeled columns:
   • PO_Number, PO_Date
   • Ship_To_Name, Ship_To_Address, Ship_To_City, Ship_To_State, Ship_To_ZIP
   • Line_Number, SKU, UPC, Description, Quantity, Unit_Price
   • Ship_By_Date, Delivery_Date (Walmart MABD, Target requested date, Amazon delivery window)
   • Department_Number (Walmart REF*DP), TCIN (Target), ASIN (Amazon)
4. Download CSV (requires PlainEDI account: $99/month unlimited files)

Step 3: Import CSV to Your WMS

Option A: Manual Import (Excel → WMS data entry)

• Open CSV in Excel
• Manually enter customer address and line items into your WMS
• Best for: 5-10 orders/day

Option B: WMS CSV Import Tool

• ShipStation: Import orders via CSV (Settings → Import/Export → CSV Import)
• ShipHero: CSV order import (Orders → Import Orders → Upload CSV)
• 3PL Central: CSV import via SmartScan (requires CSV mapping setup)
• NetSuite: CSV import with SuiteScript for automated processing
• Best for: 10-50 orders/day

Option C: Automated CSV Import (Zapier/Make.com integration)

• Set up Zapier workflow: New email with .edi attachment → PlainEDI API (if available) → Parse to CSV → Import to WMS
• Or use Make.com (formerly Integromat) for similar automation
• Best for: 50+ orders/day, technical team available

Step 4: Fulfill Order in Your Warehouse

• WMS generates pick list from imported CSV data
• Warehouse staff picks items from shelves
• Pack with client-provided packaging or retailer-specific packing slip (Walmart/Target/Amazon branding)
• Print shipping label from WMS (integrated with UPS/FedEx/USPS)
• Ship order, collect tracking number

Step 5: Generate EDI 856 ASN Data

Data needed for 856 ASN:

• Original PO number (from 850 PO)
• Tracking number (from carrier)
• Carrier name: SCAC code (UPS = UPGF, FedEx = FDEG, USPS = USPS)
• Ship date (actual ship date, not estimated)
• Items shipped: SKU, quantity (must match 850 PO)

Method A: Export CSV from WMS, manually enter to retailer portal

• Export shipment data from WMS as CSV (most WMS support shipment export)
• Open CSV, copy tracking numbers
• Submit ASN via Walmart DSV Portal / Amazon Vendor Central / Target Partners Online (web form, no EDI required)

Method B: Client submits ASN (you email them tracking)

• Export shipment CSV from WMS
• Email CSV to client with tracking numbers
• Client submits 856 ASN to retailer on your behalf

Method C: Generate EDI 856 file (advanced)

• Use EDI 856 template with your WMS shipment data
• Some WMS (NetSuite, 3PL Central) can generate 856 files directly
• Submit 856 via retailer portal or VAN/AS2 (if you have EDI transmission setup)

Managing Multiple Clients with Different EDI Requirements

3PL warehouses typically serve 5-20 clients, each with unique EDI formats and retailer relationships. Here's how to manage multi-client EDI efficiently:

Challenge: Client A (Walmart), Client B (Target), Client C (Amazon)

• Client A: Walmart 850 POs with MABD dates in DTM*002, department numbers in REF*DP
• Client B: Target 850 POs with TCIN in PO1 VA qualifier, requested delivery dates
• Client C: Amazon 850 POs with ASIN, strict 4-hour ASN requirement

Solution: PlainEDI automatically handles retailer-specific parsing

• Upload Walmart 850 PO → PlainEDI extracts MABD date, department number, ship-to GLN automatically
• Upload Target 850 PO → PlainEDI extracts TCIN, requested date, ship-to address
• Upload Amazon 850 PO → PlainEDI extracts ASIN, delivery window, FC (fulfillment center) address
• All converted to standardized CSV format your WMS can import

Challenge: Client D Uses EDI 940 (Not 850)

Some clients send EDI 940 Warehouse Shipping Order instead of forwarding retail 850 POs.

Solution: PlainEDI parses all X12 EDI formats (850, 940, 856, 810, 820, 846, 997). Upload 940 file, get CSV with same order details.

Challenge: Client E Requires EDI 943 Inventory Receipts

When you receive Client E's inventory shipment, they want EDI 943 notification.

Solution options:

• Manual: Export your WMS receiving data as CSV, email to client
• WMS integration: Some WMS (3PL Central, NetSuite) can generate 943 files directly
• Hybrid: Use PlainEDI to understand 943 structure (upload sample 943 from another client, study CSV output), then create your own 943 templates

Organizing Multi-Client EDI Files

Best practices:

• Create separate email folders for each client (Gmail labels, Outlook folders)
• Name convention for downloaded EDI files: ClientA_Walmart_850_PO123456_2025-10-20.edi
• Convert all EDI files to CSV daily, store in client-specific folders
• Batch import to WMS: Process all Client A orders at once, then Client B, etc.

When 3PLs Should Graduate to Full EDI Integration

CSV conversion works well for smaller 3PLs, but full EDI integration becomes cost-effective at scale. Here's the decision framework:

Keep Using PlainEDI CSV Method If:

• ✅ You process <100 orders/day total across all clients
• ✅ You have 1-5 clients
• ✅ Most clients use retailer web portals for ASN submission (Retail Link, Partners Online, Vendor Central)
• ✅ Your WMS supports CSV import
• ✅ Manual processing time is <2 hours/day

Cost: $99/month PlainEDI + 2 hours/day labor at $25/hr = $99 + $1,250 labor = $1,349/month

Graduate to Full EDI Integration When:

• ✅ You process 100+ orders/day per client
• ✅ You have 10+ clients with EDI requirements
• ✅ Clients demand real-time EDI transmission (not email/portal)
• ✅ Your WMS has native EDI integration (3PL Central, NetSuite, SAP)
• ✅ Manual CSV processing exceeds 4+ hours/day (labor cost justifies automation)
• ✅ Clients willing to pay for EDI integration ($100-$500/month premium)

Cost: $15,000-$75,000 one-time setup per client + $500-$2,000/month per client ongoing

ROI: At 500+ orders/month per client, labor savings justify EDI cost

Hybrid Approach (Best for Growing 3PLs)

Strategy: Use full EDI for high-volume clients, CSV conversion for smaller clients

• Tier 1 clients (500+ orders/month): Full EDI integration via SPS Commerce, TrueCommerce, or Orderful
• Tier 2 clients (50-500 orders/month): PlainEDI CSV conversion + WMS CSV import
• Tier 3 clients (<50 orders/month): PlainEDI CSV conversion + manual WMS entry

Benefit: Maximize automation for high-volume clients, minimize cost for small clients. Total cost is optimized per client based on volume.

Cost-Benefit Analysis: CSV Conversion vs Full EDI Integration

Let's compare costs for a 3PL warehouse with 5 clients, each sending 200 orders/month (1,000 orders/month total):

Option 1: PlainEDI CSV Method (All 5 Clients)

• PlainEDI subscription: $99/month unlimited files
• Labor: 3 minutes per order × 1,000 orders = 50 hours/month at $25/hr = $1,250/month
• Total monthly cost: $99 + $1,250 = $1,349/month
• Annual cost: $1,349 × 12 = $16,188/year

Option 2: Full EDI Integration (All 5 Clients)

• Setup cost: $25,000 per client × 5 clients = $125,000 one-time
• Monthly EDI software: $800/month per client × 5 = $4,000/month
• Labor (reduced): 30 minutes/month monitoring × $25/hr = $12.50/month (minimal labor)
• Year 1 total cost: $125,000 + ($4,000 × 12) = $173,000
• Year 2+ annual cost: $4,000 × 12 = $48,000/year

Option 3: Hybrid Approach (Recommended)

• Client A (500 orders/month): Full EDI integration → $25,000 setup + $1,000/month = $37,000 year 1
• Clients B, C, D, E (125 orders/month each): PlainEDI CSV → $99/mo PlainEDI + 25 hours labor = $99 + $625 = $724/month = $8,688/year
• Year 1 total cost: $37,000 + $8,688 = $45,688
• Year 2+ annual cost: $12,000 (Client A EDI) + $8,688 (other clients CSV) = $20,688/year

Frequently Asked Questions

Can a 3PL warehouse operate without full EDI integration?

Yes, for smaller 3PLs (<100 orders/day). Use PlainEDI to convert client EDI files to CSV, import to your WMS, fulfill orders, and submit ASNs via retailer web portals. Full EDI is only necessary at high volumes (500+ orders/month per client) or when clients mandate real-time EDI transmission.

How do 3PLs handle EDI 856 ASN generation?

Three options:

• Web portal submission: Export shipment data from WMS, manually enter tracking to Walmart DSV / Amazon Vendor Central / Target Partners Online (no EDI required)
• Email to client: Export shipment CSV from WMS, email to client, client submits ASN
• Generate EDI 856: Use WMS EDI module (3PL Central, NetSuite) or EDI software to auto-generate and transmit 856 files

What WMS systems work best with PlainEDI CSV conversion?

Any WMS with CSV import capabilities:

• ShipStation: CSV order import built-in (Settings → Import/Export)
• ShipHero: Native CSV import for orders
• 3PL Central: SmartScan CSV import (requires initial mapping setup)
• NetSuite: CSV import via saved searches and SuiteScript
• Custom WMS: Most custom-built WMS support CSV via database import or API

Do 3PLs need different EDI setups for each client?

With full EDI integration: Yes, each client requires custom mapping ($25,000-$75,000 per client setup cost).

With PlainEDI CSV method: No, PlainEDI handles all X12 EDI formats (850, 940, 856, 810) and automatically extracts retailer-specific fields (Walmart MABD, Target TCIN, Amazon ASIN). Same $99/month subscription works for all clients regardless of EDI format differences.

Can I charge clients for EDI processing?

Yes, many 3PLs add EDI processing fees:

• CSV processing: $0.50-$2.00 per order for EDI to CSV conversion and WMS import
• Full EDI integration: $100-$500/month per client pass-through fee for EDI software costs
• ASN submission: $0.25-$1.00 per shipment for 856 ASN generation/submission

At $1/order EDI fee × 200 orders/month = $200/month revenue. This covers PlainEDI $99/month cost and provides profit margin.