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X12 EDI

United Natural Foods, Inc. (UNFI) X12 855 Purchase Order Acknowledgment

X12 855 (Purchase Order Acknowledgment) is the EDI transaction exchanged between United Natural Foods, Inc. (UNFI) (United Natural Foods (UNFI) US) and its trading partners. Stacksync handles full compliance, mapping, and real-time delivery.

Segments
13
Loops
4
X12 855
All partners ↗

Transaction context

Where 855 Purchase Order Acknowledgment fits on United Natural Foods (UNFI) US

On United Natural Foods (UNFI) US, the X12 855 Purchase Order Acknowledgment follows the 850 Purchase Order and precedes the 856 Ship Notice Manifest and 810 Invoice in the Order-to-cash cycle.

United Natural Foods, Inc. (UNFI) channels
2 of 4

2 of United Natural Foods, Inc. (UNFI)'s 4 channels carry 855

Trading partners
269

partners across the Stacksync network trade 855

Channels
328

channels network-wide carry 855

The 855 is the seller's formal response to an 850 purchase order: accept as submitted, accept with changes to price, quantity, dates, or items, or reject. Buyers require it to confirm the order is committed before shipment and to surface availability, pricing, and item discrepancies while there is still time to correct them. Many retail compliance programs mandate it within a defined window, commonly 24 to 48 hours of PO receipt, and failure to send required response documents on time can result in financial penalties under vendor compliance programs. Sent by the supplier or vendor to the buyer that issued the purchase order.

When it fires: A supplier's order management system finishes validating an inbound purchase order against its item master, pricing, and available inventory.

Common 855 rejection causes
  • Acknowledgments sent after the buyer's required response window, commonly 24 to 48 hours, exposing the supplier to compliance penalties.
  • PO number or line references that do not match the original 850, so the buyer's system cannot tie the acknowledgment back to the order.
  • Inaccurate product identifiers or prices echoed back on the acknowledgment, creating discrepancies that persist into the ship notice and invoice.
  • Missing or inconsistent acknowledgment status codes, leaving the buyer unsure whether changed quantities, dates, or backorders were actually committed.

Specification summary

X12 855 Purchase Order Acknowledgment at the element level

The X12 855 specification defines 54 segments carrying 204 data elements, 72 of which are mandatory.

Segments
54
Data elements
204
Mandatory elements
72
Segments with mandatory elements
Segment Elements Mandatory
BAK 6 4
CUR 2 2
REF 3 1
FOB 3 1
SAC 10 1
DTM 4 1
TXI 7 1
N9 3 1
MSG 2 1
N1 4 1
N2 2 1
Key identifiers in 855
  • Transaction Set Purpose Code
  • Acknowledgment Type
  • Purchase Order Number
  • Date
  • Entity Identifier Code
  • Currency Code
  • Reference Identification Qualifier
  • Shipment Method of Payment
Full segment guideline — 13 segments 4 loops · X12 855 Purchase Order Acknowledgment
ISA Interchange Control Header 16 elements

To start and identify an interchange of zero or more functional groups and interchange-related control segments

GS Functional Group Header 8 elements

To indicate the beginning of a functional group and to provide control information

ST Transaction Set Header 2 elements

To indicate the start of a transaction set and to assign a control number

BAK Beginning Segment for Purchase Order Acknowledgment 4 elements

To indicate the beginning of the Purchase Order Acknowledgment Transaction Set and transmit identifying numbers and dates

REF Reference Identification 2 elements

To specify identifying information

N1 Loop Repeat: 200
N1 Name 4 elements

To identify a party by type of organization, name, and code

N3 Address Information 1 element

To specify the location of the named party

N4 Geographic Location 3 elements

To specify the geographic place of the named party

PO1 Loop Repeat: 100,000
PO1 Baseline Item Data 13 elements

To specify basic and most frequently used line item data

ACK Loop Repeat: 104
ACK Line Item Acknowledgment 15 elements

To acknowledge the ordered quantities and specify the ready date for a specific line item

DTM Date/Time Reference 2 elements

To specify pertinent dates and times

CTT Loop Repeat: 1
CTT Transaction Totals 1 element

To transmit a hash total for a specific element in the transaction set

SE Transaction Set Trailer 2 elements

To indicate the end of the transaction set and provide the count of the transmitted segments (including the beginning (ST) and ending (SE) segments)

Trading partners

1+ trading partners.
And every channel covered.

We connect to every major retailer, distributor, and 3PL on the EDI network. Type to search the directory, or browse the full catalogue.

Browse the full directory

Trading partners

4+ trading partners.
And every channel covered.

We connect to every major retailer, distributor, and 3PL on the EDI network. Type to search the directory, or browse the full catalogue.

United Natural Foods, Inc. (UNFI) United Natural Foods (UNFI) US EDI 855 FAQ

Common questions about 855 Purchase Order Acknowledgment on the United Natural Foods (UNFI) US channel.

What is X12 855 Purchase Order Acknowledgment?
X12 855 (Purchase Order Acknowledgment) is the EDI transaction set used to exchange purchase order acknowledgment data. United Natural Foods, Inc. (UNFI)'s United Natural Foods (UNFI) US channel requires it from trading partners.
Does United Natural Foods, Inc. (UNFI) United Natural Foods (UNFI) US require 855 for trading partners?
Yes, United Natural Foods, Inc. (UNFI) (United Natural Foods (UNFI) US) supports X12 855 Purchase Order Acknowledgment. Stacksync handles the full integration so your team can focus on operations.
How fast can I integrate United Natural Foods, Inc. (UNFI) 855 with Stacksync?
Most companies go live with United Natural Foods, Inc. (UNFI) 855 on Stacksync in days. Pre-built mappings, no-code setup, and real-time monitoring make EDI compliance straightforward.
Which other United Natural Foods, Inc. (UNFI) channels accept 855?
X12 855 runs on 2 of United Natural Foods, Inc. (UNFI)'s 4 channels. Besides United Natural Foods (UNFI) US, it is accepted on UNFI Conventional (Legacy Supervalu). Each channel carries its own implementation guideline; Stacksync validates outbound documents against the correct guideline automatically.

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