What Is EDI 856? The Complete Guide to Advance Ship Notices (ASN)

What Is EDI 856?

The EDI 856, also known as the Advance Ship Notice (ASN) or Ship Notice/Manifest, is an electronic document that a supplier sends to a buyer before a shipment arrives, detailing exactly what products are being shipped, how they're packaged, and when they'll arrive. It is one of the most critical — and most error-prone — EDI documents in retail and manufacturing supply chains.

Think of the EDI 856 as a digital packing slip on steroids. While a traditional packing slip tells you what's in a box, the ASN tells the receiving warehouse everything it needs to know before a single carton hits the dock: which purchase orders are fulfilled, what items are in each carton, how cartons are stacked on pallets, which carrier is delivering them, and exactly when they'll arrive.

Definition: EDI 856 (Advance Ship Notice / ASN) — An electronic document defined by the ANSI ASC X12 standard (Transaction Set 856) that provides detailed shipment information from a supplier to a buyer before delivery. The ASN enables automated receiving, cross-docking, and inventory management by linking electronic data to physical shipment contents through unique identifiers like the SSCC-18.

Why the ASN Is Called the "Most Critical" EDI Document

Every major retailer — Walmart, Costco, Target, Amazon, Kroger, Home Depot — requires the EDI 856 from their suppliers, and most consider it the single most important compliance document. The reason is operational: modern retail warehouses use ASN data to pre-plan receiving operations. Without an accurate, timely ASN, a 40-foot truckload of products becomes a manual processing nightmare instead of an automated workflow.

The ASN is also the document that generates the most chargebacks. Industry estimates suggest that ASN-related errors account for more supplier penalties than any other EDI document type, with retailers levying fees of $25–$200 per incident for inaccurate or late ASNs.

How Does the EDI 856 Work in the Supply Chain?

The EDI 856 ASN fits into the order-to-cash cycle between the purchase order (EDI 850) and the invoice (EDI 810), transmitted by the supplier after shipment leaves the facility but before it arrives at the buyer's warehouse. This timing window is what makes the ASN so valuable — it gives the receiving team advance notice to prepare dock assignments, labor allocation, and inventory placement.

The EDI 856 in the Order-to-Cash Flow

Here's how the ASN fits into the complete transaction lifecycle:

1. Buyer sends EDI 850 (Purchase Order) — The retailer orders products from the supplier
2. Supplier sends EDI 855 (PO Acknowledgment) — The supplier confirms they can fulfill the order
3. Supplier picks, packs, and ships the order — Physical fulfillment occurs in the warehouse
4. Supplier sends EDI 856 (Advance Ship Notice) — Sent immediately after shipment leaves the dock
5. Buyer receives and scans shipment — The warehouse matches physical cartons to ASN data
6. Supplier sends EDI 810 (Invoice) — The supplier bills for goods shipped
7. Buyer sends EDI 820 (Payment/Remittance) — The buyer pays the supplier

What Happens When the ASN Arrives

When a retailer's warehouse management system (WMS) receives an EDI 856, it triggers a chain of automated actions:

• Dock scheduling — The WMS assigns an inbound dock door based on the shipment's contents and destination
• Labor planning — The system calculates how many workers are needed to unload and process the shipment
• Cross-dock routing — For products going directly to store shelves, the WMS pre-determines routing before the truck arrives
• Inventory pre-allocation — Products are virtually allocated to storage locations before physical receipt
• Barcode validation — When cartons are scanned at the dock, each SSCC-18 barcode is instantly matched against the ASN data

This automation is why the EDI 856 must be sent before the shipment arrives. If the ASN shows up after the truck, the entire automated receiving process falls back to manual handling — which is slower, more expensive, and more error-prone.

EDI 856 Document Structure: Segments and Hierarchical Levels

The EDI 856 follows the ANSI ASC X12 standard and uses a hierarchical structure (HL segments) to describe shipment contents at multiple levels — from the overall shipment down to individual items within each carton. This nested structure is what makes the ASN both powerful and complex.

The Four Hierarchical Levels

The EDI 856's defining feature is its hierarchical loop structure. Each level describes a different layer of the shipment's physical packaging:

EDI 856 Hierarchical Levels — The four standard HL levels that describe the physical structure of a shipment from top to bottom

The hierarchy works like a tree:

Shipment (HL Level S)
├── Order 1 (HL Level O) — PO #12345
│   ├── Pallet 1 (HL Level P) — SSCC 00012345678901234567
│   │   ├── Carton 1 (HL Level P) — SSCC 00012345678901234568
│   │   │   ├── Item A — UPC 012345678901 × 24 units
│   │   │   └── Item B — UPC 012345678902 × 12 units
│   │   └── Carton 2 (HL Level P) — SSCC 00012345678901234569
│   │       └── Item A — UPC 012345678901 × 24 units
│   └── Pallet 2 (HL Level P) — SSCC 00012345678901234570
│       └── Carton 3 (HL Level P) — SSCC 00012345678901234571
│           └── Item C — UPC 012345678903 × 48 units
└── Order 2 (HL Level O) — PO #12346
    └── Carton 4 (HL Level P) — SSCC 00012345678901234572
        └── Item D — UPC 012345678904 × 36 units

Key EDI 856 Segments

Each hierarchical level contains specific data segments that carry the actual shipment information:

EDI 856 Key Segments — The most important data segments within the ASN and what information each carries

X12 Version Requirements

The EDI 856 is implemented under specific versions of the ANSI X12 standard. The most commonly used versions are:

• X12 4010 — The most widely adopted version across retail. Walmart, Costco, Target, and most major retailers use 4010 for their ASN requirements.
• X12 5010 — A newer version used by some trading partners, particularly in healthcare and government sectors.

Your EDI solution must support the exact version specified in each trading partner's Implementation Guide (IG). Using the wrong version causes document rejections.

What Information Does an EDI 856 Contain?

A complete EDI 856 ASN contains four categories of information: shipment-level logistics, order-level references, pack-level container identification, and item-level product details. Every data point must match the physical shipment exactly — discrepancies trigger chargebacks.

Shipment-Level Data

Information about the overall delivery:

• Shipment ID — A unique number identifying this specific ASN
• Ship date and time — When the shipment left your facility
• Estimated delivery date — When it's expected to arrive
• Carrier information — Carrier name, SCAC code (Standard Carrier Alpha Code)
• Bill of Lading number — The shipping contract reference
• Trailer/container number — Physical equipment identifier
• Total weight and carton count — Aggregate shipment metrics
• Ship-from address — Your warehouse or distribution center
• Ship-to address — The retailer's specific warehouse or DC location

Order-Level Data

Information linking the shipment back to purchase orders:

• Purchase order number(s) — Which POs this shipment fulfills
• PO date — When the order was placed
• Department or buyer code — Internal retailer routing information

Pack-Level Data (Tare)

Information about physical containers:

• SSCC-18 code — A unique 18-digit Serial Shipping Container Code for each carton and pallet
• Carton weight and dimensions — Physical measurements
• Packaging type — Carton, pallet, case, etc.
• Pack count — "Carton X of Y" within the shipment

Item-Level Data

Information about the products inside each container:

• UPC/GTIN — The product's barcode identifier
• Vendor SKU — Your internal product number
• Buyer item number — The retailer's internal item code
• Quantity — Number of units in this container
• Unit of measure — Each, case, pack, etc.
• Lot number — For products requiring lot tracking
• Expiration date — For perishable or date-sensitive products
• Item description — Text description of the product

EDI 856 Example: What an ASN Actually Looks Like

An EDI 856 in its raw X12 format is a series of data segments separated by element delimiters, with each segment on its own line identified by a 2-3 character code. Here's a simplified but realistic example showing a single-order, two-carton shipment.

Raw EDI 856 Format

ST*856*0001~
BSN*00*SH20260218001*20260218*1430*0001~
DTM*011*20260218~
DTM*017*20260220~
HL*1**S~
TD1*CTN*2****G*150*LB~
TD5**2*UPSN*M~
REF*BM*BOL20260218001~
N1*SF*Acme Products Inc*92*ACME001~
N1*ST*Walmart DC 6023*92*0078742006023~
HL*2*1*O~
PRF*PO4501234567~
HL*3*2*P~
MAN*GM*00100123456789012345~
HL*4*3*I~
LIN**UP*012345678901*VP*ACME-SKU-100~
SN1**24*EA~
PID*F****Organic Protein Bars, Chocolate, 12-Pack~
HL*5*2*P~
MAN*GM*00100123456789012346~
HL*6*5*I~
LIN**UP*012345678901*VP*ACME-SKU-100~
SN1**24*EA~
PID*F****Organic Protein Bars, Chocolate, 12-Pack~
CTT*6~
SE*24*0001~

Segment-by-Segment Breakdown

Here's what each line means:

This example shows the fundamental pattern: shipment → order → carton → item, with each level linked to its parent through the HL segment's parent reference number.

Why Is the EDI 856 So Important?

The EDI 856 is the single most operationally critical EDI document because it enables automated warehouse receiving, prevents chargebacks, and directly impacts a retailer's ability to maintain accurate inventory and fulfill customer orders on time. Without the ASN, modern retail logistics simply cannot function at scale.

The Business Impact by the Numbers

The data makes the case clearly:

EDI 856 Business Impact — Key statistics showing the operational and financial impact of accurate ASN implementation

Five Reasons the ASN Matters More Than Any Other Document

1. It enables automated receiving. When a warehouse scans a carton's SSCC-18 barcode, the WMS instantly pulls up all ASN data — what's inside, which PO it fulfills, and where it should go. Without the ASN, every carton must be opened and manually counted.

2. It powers cross-docking. Retailers like Walmart and Costco use cross-docking to move products from inbound trucks directly to outbound delivery vehicles. This requires knowing exactly what's on a truck before it arrives — which only the ASN provides.

3. It prevents chargebacks. ASN errors are the #1 source of supplier chargebacks across retail. Accurate ASNs eliminate the most common penalty triggers: quantity mismatches, late notifications, and SSCC errors.

4. It accelerates payment. The ASN is one leg of the three-way match (850 → 856 → 810) that retailers use to approve invoices. When the ASN matches the PO and invoice, payment is processed automatically. When it doesn't, payment stalls.

5. It improves inventory accuracy. Accurate ASN data flows into the retailer's inventory system in real time, enabling better demand forecasting, replenishment planning, and stock availability.

EDI 856 Requirements by Major Retailer

Every major retailer requires the EDI 856, but each has unique specifications for timing, data elements, and compliance penalties. Understanding these differences is essential for suppliers who sell to multiple retailers.

Retailer EDI 856 ASN Requirements — How ASN specifications differ across the top six U.S. retailers

For detailed, retailer-specific guides, see:

• Walmart EDI Requirements: Complete 2026 Guide
• Costco EDI Requirements: Complete 2026 Guide
• Target EDI Requirements: Complete 2026 Guide
• Amazon EDI Requirements: Complete 2026 Guide
• UNFI EDI Requirements: Complete 2026 Guide

The Multi-Retailer Challenge

If you sell to multiple retailers, each requires a different ASN implementation. Walmart demands AS2 protocol with OTIF tracking. Costco uses VAN connections with a three-way match system. Target requires AS2 with strict on-time delivery windows. Managing these differences manually is where most compliance failures occur.

This is why many growing brands turn to cloud-based EDI platforms that maintain pre-built retailer maps — the platform handles the translation so you don't need to manage separate implementations for each trading partner.

Common EDI 856 Errors and How to Fix Them

The most common EDI 856 errors fall into five categories: SSCC mismatches, quantity discrepancies, timing violations, missing data, and hierarchy errors. Each type triggers specific chargebacks and has specific root causes that can be systematically eliminated.

Error Type 1: SSCC Mismatch

What happens: The SSCC-18 barcode on the physical carton doesn't match the SSCC in the ASN data. When the warehouse scans the carton, the WMS can't find a matching record.

Root cause: Labels are generated from one system (e.g., a label printer template) while ASN data is generated from another (e.g., the ERP). The two systems aren't synchronized.

Fix: Generate both GS1-128 labels and ASN data from the same source system. Most modern EDI platforms create the SSCC, generate the label, and populate the ASN simultaneously — making mismatches impossible.

Error Type 2: Quantity Discrepancy

What happens: The ASN says 24 units in a carton, but the physical carton contains 23. Or the ASN shows 10 cartons but only 9 arrive.

Root cause: Packing errors on the warehouse floor. A picker short-ships a carton but the ASN reflects the original planned quantity, not the actual quantity.

Fix: Implement scan-based verification at the packing station. When a carton is sealed, scan every item to confirm the count matches before the ASN is generated. The ASN should be created from actual shipment data, not planned data.

Error Type 3: Late or Missing ASN

What happens: The ASN arrives after the physical shipment, or isn't sent at all. The receiving warehouse can't pre-plan operations.

Root cause: Manual ASN generation — someone has to remember to create and send it. Or system delays between shipment confirmation and EDI transmission.

Fix: Automate ASN generation to trigger immediately when a shipment is confirmed. The EDI system should detect the shipment event (e.g., carrier pickup scan) and transmit the 856 within minutes, not hours.

Error Type 4: Missing or Incorrect Data Elements

What happens: Required fields are blank or contain wrong values — missing carrier SCAC code, wrong ship-to location, incorrect PO number.

Root cause: Incomplete data mapping between your internal systems and the retailer's EDI specifications. Or master data errors (e.g., wrong location codes in your ERP).

Fix: Implement pre-transmission validation that checks every ASN against the trading partner's specific requirements before sending. Flag and block any document that fails validation rules.

Error Type 5: Hierarchy Errors

What happens: The parent-child relationships in the HL segments are wrong — items assigned to the wrong carton, cartons assigned to the wrong pallet, or missing hierarchy levels.

Root cause: Complex multi-carton, multi-pallet shipments where the nesting isn't correctly mapped between the physical packing process and the EDI document.

Fix: Ensure your WMS captures the actual physical packaging hierarchy during packing (which item goes in which carton, which carton goes on which pallet) and passes this structure directly to the EDI system.

Best Practices for EDI 856 Compliance

The key to EDI 856 compliance is a three-part strategy: automate ASN generation from actual shipment data, validate every document before transmission, and monitor compliance metrics continuously. Companies that follow these practices see chargeback reductions of 80% or more.

1. Automate ASN Generation

Manual ASN creation is the root cause of most compliance failures. Automation means:

• Trigger ASN on shipment event — The 856 should generate automatically when a carrier pickup is confirmed, not when someone remembers to create it
• Pull data from WMS — Actual carton contents, weights, and SSCC codes should flow directly from your warehouse management system
• Eliminate manual data entry — Every field should be populated programmatically from source systems

2. Validate Before You Transmit

Every ASN should pass through validation rules before it leaves your system:

• Format validation — Does the document conform to the X12 standard and the specific trading partner's IG?
• Logical validation — Do quantities in the ASN match the original PO? Are all required fields populated?
• SSCC validation — Is every SSCC unique? Does each SSCC map to exactly one physical carton?
• Reference validation — Are PO numbers, item numbers, and location codes all correct?

3. Use a Single Source of Truth

The #1 rule for ASN accuracy: labels and electronic data must come from the same source.

• Generate SSCC codes once — Create SSCC-18 codes in one system, then use those same codes for both GS1-128 labels and ASN data
• Capture actual quantities — ASN quantities should reflect what was physically packed and scanned, not what was planned
• Sync master data — Product codes, location codes, and trading partner identifiers must be consistent across all systems

4. Monitor and Audit Continuously

Compliance isn't a one-time setup — it's an ongoing practice:

• Track chargeback trends — Review penalty reports monthly and trace each chargeback to its root cause
• Monitor ASN timing — Set up alerts for any ASN that isn't transmitted within your target window after shipment
• Audit error rates — Track the percentage of ASNs that pass first-time validation and work to drive it above 99%
• Review retailer scorecards — Most retailers provide compliance dashboards (e.g., Walmart's Retail Link OTIF reports). Review these weekly.

5. Test Before Going Live

Certification testing with each trading partner is mandatory, but thorough internal testing is equally important:

• Test every scenario — Full carton, partial carton, multi-PO shipment, multi-pallet shipment, hazmat items, perishables
• Verify end-to-end — Don't just test that the 856 generates correctly — test that it's received, parsed, and acknowledged (via EDI 997) by the trading partner
• Document edge cases — When you find issues during testing, document them and add validation rules to prevent them in production

For a comprehensive testing guide, see our article on avoiding EDI chargebacks, which covers validation strategies across all major EDI documents.

EDI 856 vs. Other Shipping Documents

The EDI 856 ASN is distinct from other shipping documents in that it's sent electronically before the shipment arrives and contains detailed carton-level packaging data that other documents don't include. Understanding these differences clarifies why the ASN is required in addition to traditional shipping paperwork.

EDI 856 vs. Other Shipping Documents — How the Advance Ship Notice compares to other common shipping and logistics documents

Why the ASN Can't Be Replaced by Other Documents

• Bill of Lading tells the carrier what's on the truck but doesn't detail carton contents or SSCC codes
• Packing slips are inside cartons and can only be read after opening — too late for automated receiving
• Carrier tracking shows where a package is but not what's inside it
• The EDI 810 invoice describes what you're billing for, not what you physically shipped

Only the EDI 856 combines all three critical elements: it arrives before the shipment, it details carton-level contents linked to SSCC barcodes, and it's in a machine-readable format that integrates with warehouse management systems.

Frequently Asked Questions

What is EDI 856 used for?

The EDI 856 is used to electronically communicate the contents of a shipment to a trading partner before the shipment arrives at their facility. It enables the receiving warehouse to pre-plan dock assignments, allocate labor, set up cross-docking, and validate incoming cartons by scanning SSCC-18 barcodes against the ASN data. Every major retailer requires it for automated receiving.

What is the difference between EDI 855 and 856?

The EDI 855 is a Purchase Order Acknowledgment — it confirms that a supplier received and accepted a purchase order. The EDI 856 is an Advance Ship Notice — it provides detailed shipment information after goods have been picked, packed, and shipped. The 855 comes before fulfillment ("yes, we can fill this order"), while the 856 comes after fulfillment ("here's exactly what we shipped"). Both are required by most major retailers.

What is the difference between EDI 810 and 856?

The EDI 810 is an Invoice — it's a bill sent from the supplier to the buyer for goods shipped. The EDI 856 is an Advance Ship Notice — it describes the physical contents and packaging of a shipment. The 856 is sent before or at the time of shipment, while the 810 is typically sent after shipment. Together with the EDI 850 (Purchase Order), they form the three-way match that retailers use to verify and approve payments.

What does an EDI 856 contain?

An EDI 856 contains four levels of information organized hierarchically: (1) Shipment-level data including carrier, dates, and ship-to/from addresses; (2) Order-level data linking to specific purchase orders; (3) Pack-level data with SSCC-18 codes for each physical carton and pallet; and (4) Item-level data including UPC/GTIN, quantities, descriptions, and lot numbers for products within each container.

How soon must the EDI 856 be sent after shipment?

Timing varies by retailer. Walmart requires ASNs within 30 minutes of carrier pickup. Most other retailers require the ASN to arrive before the physical shipment — best practice is to transmit the 856 immediately after the shipment leaves your facility, ideally within minutes. Late ASNs trigger chargebacks ranging from $25 to $500 per incident depending on the retailer.

What is SSCC-18 and how does it relate to EDI 856?

SSCC-18 (Serial Shipping Container Code) is a unique 18-digit identifier assigned to each physical carton or pallet in a shipment. The SSCC is embedded in a GS1-128 barcode label on the carton and is also included in the EDI 856 ASN data (in the MAN segment). When a retailer scans the barcode at receiving, the system matches it to the ASN to instantly identify what's in the carton. A mismatch between the scanned SSCC and the ASN data triggers a chargeback.

What are common EDI 856 errors that cause chargebacks?

The five most common EDI 856 errors are: (1) SSCC mismatches — barcode on the carton doesn't match the ASN; (2) Quantity discrepancies — ASN quantity differs from actual carton contents; (3) Late or missing ASNs — the 856 arrives after the physical shipment; (4) Missing data elements — required fields like carrier SCAC code or PO number are blank; and (5) Hierarchy errors — items assigned to wrong cartons in the HL segment structure.

Can I generate EDI 856 manually?

Technically yes, but it's strongly discouraged. Manual ASN creation is the leading cause of errors and chargebacks. A single typo in an SSCC code, quantity, or PO number triggers a financial penalty. For suppliers handling more than a few shipments per week, automated ASN generation integrated with your WMS is essential. Modern cloud EDI platforms automate the entire process — from SSCC creation to label printing to ASN transmission.

What happens if I don't send an EDI 856?

If you don't send an ASN, the retailer's warehouse cannot use automated receiving. Every carton must be manually opened, counted, and verified — a process that's 10x slower than scan-based receiving. You will receive chargebacks for the missing ASN, your shipment will likely be deprioritized at the dock, and repeated failures can result in order reductions or loss of the trading partnership.

How does the EDI 856 relate to GS1-128 labels?

GS1-128 labels and the EDI 856 are two sides of the same coin. The GS1-128 label is the physical barcode on each carton containing the SSCC-18 code. The EDI 856 is the electronic document that maps each SSCC to its contents. When a retailer scans a GS1-128 label, the system looks up that SSCC in the ASN to determine what's in the carton. Both must be generated from the same source data — if labels come from one system and the ASN from another, mismatches are nearly guaranteed.

Conclusion: Mastering the EDI 856

The EDI 856 Advance Ship Notice is the backbone of modern retail logistics. It's the document that makes automated receiving, cross-docking, and real-time inventory management possible at scale. It's also the document that generates the most chargebacks when errors occur.

The key takeaways:

1. The EDI 856 is mandatory — Every major retailer requires it, and there's no viable manual alternative
2. Accuracy is non-negotiable — Every data point in the ASN must match the physical shipment exactly
3. Timing matters — The ASN must arrive before the shipment, ideally within minutes of carrier pickup
4. Automation prevents errors — Manual ASN creation is the root cause of most chargebacks
5. Each retailer is different — Walmart, Costco, Target, and Amazon all have unique ASN specifications
6. Labels and data must match — SSCC-18 codes in GS1-128 labels and EDI 856 data must come from the same source

Whether you're implementing EDI 856 for the first time or optimizing an existing setup to reduce chargebacks, the path forward is the same: automate generation, validate before transmission, and monitor continuously.

Need help with EDI 856 implementation? Crstl's AI-powered EDI platform automates ASN generation, pre-validates every document against retailer-specific rules, and provides real-time compliance monitoring across Walmart, Costco, Target, Amazon, and 100+ other trading partners.

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