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X12 transaction code

EDI 855 Purchase Order Acknowledgment (X12 855)

EDI 855 is the PO acknowledgment, the X12 Purchase Order Acknowledgment transaction set, used when a seller responds to an order. The supplier or vendor sends the 855 to the buyer that issued the purchase order.

Standard
X12
Code
855
Partner references
269
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At a glance

EDI 855 at a glance

What the 855 carries, who sends it to whom, when it goes out, and the segments trading partners list for it.

X12 855 Purchase Order Acknowledgment summary
Document X12 855 Purchase Order Acknowledgment
Business record Purchase-order response
Who sends it to whom The supplier or vendor sends the 855 to the buyer that issued the purchase order.
When it is sent A supplier's order management system finishes validating an inbound purchase order against its item master, pricing, and available inventory.
Match on Original purchase order, response revision and order line
Partner references 269 trading partners in this directory
Related documents X12 850 Purchase Order, X12 856 Ship Notice/Manifest, X12 860 Purchase Order Change Request (Buyer Initiated)

Key segments in an EDI 855

The business segments that appear in at least half of the 323 partner document references listed below, most common first. The table leaves out envelope segments (ISA, GS, ST, SE, GE, IEA). Your partner guide sets which segments and elements your account must send.

Segment Name Purpose Partner references
BAK Beginning Segment for Purchase Order Acknowledgment To indicate the beginning of the Purchase Order Acknowledgment Transaction Set and transmit identifying numbers and dates. 323 of 323
PO1 Baseline Item Data To specify basic and most frequently used line item data. 321 of 323
CTT Transaction Totals To transmit a hash total for a specific element in the transaction set. 307 of 323
ACK Line Item Acknowledgment To acknowledge the ordered quantities and specify the ready date for a specific line item. 300 of 323
PID Product/Item Description To describe a product or process in coded or free-form format. 215 of 323
REF Reference Information To specify identifying information. 193 of 323
N1 Party Identification To identify a party by type of organization, name, and code. 186 of 323

Stacksync connects EDI documents such as the X12 855 to your ERP, CRM and databases with two-way sync. Read the EDI overview, check pricing and security, or book a demo to walk through your partner guide.

Implementation guide

X12 855 mapping and validation

X12 855 Purchase Order Acknowledgment is used when a seller responds to an order. Preserve original purchase order, response revision and order line so the purchase-order response in your business system stays connected to the original document.

Use the version and implementation guide agreed with your trading partner to confirm required fields and responses.

Map records and test the business result
Document or decisionRecord and matching IDsWhat to test
Match the business record purchase-order response

original purchase order, response revision and order line
  • Define which combination of original purchase order, response revision and order line identifies one business record, its lines and any later revision.
Update the receiving system Processing the purchase-order response

ID assigned by the receiving system and processing result
  • Test a partially accepted order with a backordered line and retain both outcomes.
  • Do not treat a syntax acknowledgment as acceptance of price, quantity or delivery dates.
Check the processing result Processing status for the purchase-order response

Original document reference and matching response
  • Reconcile the purchase-order response with the source after a timeout before sending it again. A lost response can occur after the destination has already processed the document.

How the related documents differ

Each message represents a different business event. Use shared references to connect the records while tracking each message’s outcome separately.

Implementation steps

  1. Choose the starting event and owner

    Decide which application acts when a seller responds to an order. Name the operational owner of the purchase-order response and the team that resolves rejected or ambiguous messages.

  2. Keep record IDs connected

    Map original purchase order, response revision and order line. Confirm qualifiers, code lists, units and date/time meaning against the agreed X12 version and partner guide. Preserve the source reference alongside any new destination identifier.

  3. Test failures before launch

    Run the failure cases in the mapping table against realistic purchase-order response data. Check how the receiving system reports a rejection and how your team corrects it without creating a duplicate.

  4. Track every document to completion

    Record transport delivery and document validation separately from successful purchase-order response processing. Give unresolved errors an owner and check the receiving system before approving retries.

Go-live checklist

  • An approved 855 sample and the agreed version and partner guide are available.
  • The mapping tests pass with realistic purchase-order response data.
  • Each submitted document can be traced through delivery, validation and processing in the receiving system.
  • Your team knows how to investigate and recover a rejected or timed-out purchase-order response without processing it twice.

Document structure

X12 855 Purchase Order Acknowledgment at the element level

The X12 855 reference contains 54 segment entries and 204 data elements; 72 are marked mandatory in this reference. Use the version and partner guide agreed for your account to confirm required fields.

Segments
54
Data elements
204
Mandatory elements
72
Segments with elements marked mandatory in this reference
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

Find your trading partner for X12 855

269 partners, 328 channels. Choose a channel to inspect its listed document reference and implementation context.

Catalog breakdown

Where X12 855 Purchase Order Acknowledgment appears in this catalog

The largest groups of classified 855 catalog entries are in grocery & food, retail and building & hardware.

By industry

  • grocery & food 53 channels
  • retail 47 channels
  • building & hardware 46 channels
  • furniture & home 43 channels
  • healthcare & pharma 28 channels
  • apparel & footwear 23 channels

By network

  • SPS Commerce 87 channels
  • Epicor Eclipse 42 channels
  • TrueCommerce 26 channels
  • Rithum 8 channels
  • Logicbroker 8 channels
  • iTradeNetwork 7 channels
Partner entries with the most listed channels

FAQ

EDI 855 questions

What is an EDI 855?

EDI 855 is the PO acknowledgment, the X12 Purchase Order Acknowledgment transaction set. Trading partners use it when a seller responds to an order. It carries the data for the purchase-order response, and your system matches it on original purchase order, response revision and order line.

Who sends an EDI 855 and who receives it?

The supplier or vendor sends the 855 to the buyer that issued the purchase order. Your trading partner agreement confirms the direction and version for your account.

When is an EDI 855 sent?

A supplier's order management system finishes validating an inbound purchase order against its item master, pricing, and available inventory. Your partner guide sets any deadline or schedule for the document.

What are the key segments in an EDI 855?

Across 323 partner document references listed here, the business segments that appear most often include BAK (Beginning Segment for Purchase Order Acknowledgment), PO1 (Baseline Item Data), CTT (Transaction Totals), ACK (Line Item Acknowledgment), PID (Product/Item Description), REF (Reference Information). Each partner guide sets which segments and elements your account must send.

What is the difference between EDI 855 and EDI 850?

The 850 is the purchase order the buyer sends. The 855 answers it: the supplier accepts, changes or rejects the order, often line by line, before anything ships.

What is the difference between EDI 855 and EDI 856?

The 855 confirms what the supplier agreed to ship. The 856 reports what actually shipped, organized by shipment, order, pack and item, when the goods leave.

What should I map for X12 855?

Start with original purchase order, response revision and order line and the target purchase-order response. Define duplicate detection, allowed updates and response correlation before mapping individual fields. Use the partner guide to check required fields and their formats.

How should I test 855 error handling?

Test a partially accepted order with a backordered line and retain both outcomes. Do not treat a syntax acknowledgment as acceptance of price, quantity or delivery dates. Also test a lost response after destination processing so that a retry cannot create an unintended duplicate or repeated adjustment.

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