X12 855 PO acknowledgment: format and example

855 structure

The full X12 855 layout from its OpenEDI definition, the same model ediFabric uses to parse, validate and generate it: 19 loops and 147 segment positions, in file order. Loops are shaded and their segments indented; Max use is how many times a segment or loop may repeat.

Segment / loop	Name	Usage	Max use
`ST`	Transaction Set Header	Mandatory	1
`BAK`	Beginning Segment for Purchase Order Acknowledgment	Mandatory	1
`CUR`	Currency	Optional	1
`REF`	Reference Identification	Optional	>1
`PER`	Administrative Communications Contact	Optional	3
`TAX`	Tax Reference	Optional	>1
`FOB`	F.O.B. Related Instructions	Optional	>1
`CTP`	Pricing Information	Optional	>1
`PAM`	Period Amount	Optional	10
`CSH`	Sales Requirements	Optional	1
SAC loop	Service, Promotion, Allowance, or Charge Information	Optional	25
`SAC`	Service, Promotion, Allowance, or Charge Information	Mandatory	1
`CUR`	Currency	Optional	1
`ITD`	Terms of Sale/Deferred Terms of Sale	Optional	5
`DIS`	Discount Detail	Optional	20
`INC`	Installment Information	Optional	1
`DTM`	Date/Time Reference	Optional	10
`LDT`	Lead Time	Optional	12
`LIN`	Item Identification	Optional	5
`SI`	Service Characteristic Identification	Optional	>1
`PID`	Product/Item Description	Optional	200
`MEA`	Measurements	Optional	40
`PWK`	Paperwork	Optional	25
`PKG`	Marking, Packaging, Loading	Optional	25
`TD1`	Carrier Details (Quantity and Weight)	Optional	2
`TD5`	Carrier Details (Routing Sequence/Transit Time)	Optional	12
`TD3`	Carrier Details (Equipment)	Optional	12
`TD4`	Carrier Details (Special Handling, or Hazardous Materials, or Both)	Optional	5
`MAN`	Marks and Numbers	Optional	10
`TXI`	Tax Information	Optional	>1
`CTB`	Restrictions/Conditions	Optional	>1
N9 loop	Reference Identification	Optional	1000
`N9`	Reference Identification	Mandatory	1
`DTM`	Date/Time Reference	Optional	>1
`MSG`	Message Text	Optional	1000
N1 loop	Name	Optional	200
`N1`	Name	Mandatory	1
`N2`	Additional Name Information	Optional	2
`N3`	Address Information	Optional	2
`N4`	Geographic Location	Optional	1
`NX2`	Location ID Component	Optional	>1
`REF`	Reference Identification	Optional	12
`PER`	Administrative Communications Contact	Optional	>1
`SI`	Service Characteristic Identification	Optional	>1
`FOB`	F.O.B. Related Instructions	Optional	1
`TD1`	Carrier Details (Quantity and Weight)	Optional	2
`TD5`	Carrier Details (Routing Sequence/Transit Time)	Optional	12
`TD3`	Carrier Details (Equipment)	Optional	12
`TD4`	Carrier Details (Special Handling, or Hazardous Materials, or Both)	Optional	5
`PKG`	Marking, Packaging, Loading	Optional	25
`MSG`	Message Text	Optional	>1
ADV loop	Advertising Demographic Information	Optional	>1
`ADV`	Advertising Demographic Information	Mandatory	1
`DTM`	Date/Time Reference	Optional	>1
`MTX`	Text	Optional	>1
PO1 loop	Baseline Item Data	Optional	100000
`PO1`	Baseline Item Data	Mandatory	1
`LIN`	Item Identification	Optional	>1
`SI`	Service Characteristic Identification	Optional	>1
`CUR`	Currency	Optional	1
`PO3`	Additional Item Detail	Optional	25
`CTP`	Pricing Information	Optional	>1
`PAM`	Period Amount	Optional	10
`MEA`	Measurements	Optional	40
PID loop	Product/Item Description	Optional	1000
`PID`	Product/Item Description	Mandatory	1
`MEA`	Measurements	Optional	10
`PWK`	Paperwork	Optional	25
`PO4`	Item Physical Details	Optional	>1
`REF`	Reference Identification	Optional	>1
`PER`	Administrative Communications Contact	Optional	3
SAC loop	Service, Promotion, Allowance, or Charge Information	Optional	25
`SAC`	Service, Promotion, Allowance, or Charge Information	Mandatory	1
`CUR`	Currency	Optional	1
`IT8`	Conditions of Sale	Optional	1
`CSH`	Sales Requirements	Optional	>1
`ITD`	Terms of Sale/Deferred Terms of Sale	Optional	2
`DIS`	Discount Detail	Optional	20
`INC`	Installment Information	Optional	1
`TAX`	Tax Reference	Optional	>1
`FOB`	F.O.B. Related Instructions	Optional	>1
`SDQ`	Destination Quantity	Optional	500
`DTM`	Date/Time Reference	Optional	10
`LDT`	Lead Time	Optional	12
`TD1`	Carrier Details (Quantity and Weight)	Optional	1
`TD5`	Carrier Details (Routing Sequence/Transit Time)	Optional	12
`TD3`	Carrier Details (Equipment)	Optional	12
`TD4`	Carrier Details (Special Handling, or Hazardous Materials, or Both)	Optional	5
ACK loop	Line Item Acknowledgment	Optional	104
`ACK`	Line Item Acknowledgment	Mandatory	1
`DTM`	Date/Time Reference	Optional	1
`MAN`	Marks and Numbers	Optional	10
`AMT`	Monetary Amount	Optional	1
`CTB`	Restrictions/Conditions	Optional	>1
`TXI`	Tax Information	Optional	>1
QTY loop	Quantity	Optional	>1
`QTY`	Quantity	Mandatory	1
`SI`	Service Characteristic Identification	Optional	>1
PKG loop	Marking, Packaging, Loading	Optional	200
`PKG`	Marking, Packaging, Loading	Mandatory	1
`MEA`	Measurements	Optional	>1
SCH loop	Line Item Schedule	Optional	200
`SCH`	Line Item Schedule	Mandatory	1
`TD1`	Carrier Details (Quantity and Weight)	Optional	2
`TD5`	Carrier Details (Routing Sequence/Transit Time)	Optional	12
`TD3`	Carrier Details (Equipment)	Optional	12
`TD4`	Carrier Details (Special Handling, or Hazardous Materials, or Both)	Optional	5
`REF`	Reference Identification	Optional	>1
N9 loop	Reference Identification	Optional	1000
`N9`	Reference Identification	Mandatory	1
`DTM`	Date/Time Reference	Optional	>1
`MSG`	Message Text	Optional	1000
N1 loop	Name	Optional	200
`N1`	Name	Mandatory	1
`N2`	Additional Name Information	Optional	2
`N3`	Address Information	Optional	2
`N4`	Geographic Location	Optional	1
`NX2`	Location ID Component	Optional	>1
`REF`	Reference Identification	Optional	12
`PER`	Administrative Communications Contact	Optional	3
`SI`	Service Characteristic Identification	Optional	>1
`DTM`	Date/Time Reference	Optional	1
`FOB`	F.O.B. Related Instructions	Optional	1
`SCH`	Line Item Schedule	Optional	200
`TD1`	Carrier Details (Quantity and Weight)	Optional	2
`TD5`	Carrier Details (Routing Sequence/Transit Time)	Optional	12
`TD3`	Carrier Details (Equipment)	Optional	12
`TD4`	Carrier Details (Special Handling, or Hazardous Materials, or Both)	Optional	5
`QTY`	Quantity	Optional	>1
`PKG`	Marking, Packaging, Loading	Optional	25
SLN loop	Subline Item Detail	Optional	1000
`SLN`	Subline Item Detail	Mandatory	1
`MSG`	Message Text	Optional	>1
`SI`	Service Characteristic Identification	Optional	>1
`PID`	Product/Item Description	Optional	1000
`PO3`	Additional Item Detail	Optional	25
`CTP`	Pricing Information	Optional	25
`PAM`	Period Amount	Optional	10
`ACK`	Line Item Acknowledgment	Optional	104
SAC loop	Service, Promotion, Allowance, or Charge Information	Optional	10
`SAC`	Service, Promotion, Allowance, or Charge Information	Mandatory	1
`CUR`	Currency	Optional	1
`DTM`	Date/Time Reference	Optional	10
`PO4`	Item Physical Details	Optional	1
`TAX`	Tax Reference	Optional	3
`ADV`	Advertising Demographic Information	Optional	>1
QTY loop	Quantity	Optional	>1
`QTY`	Quantity	Mandatory	1
`SI`	Service Characteristic Identification	Optional	>1
N9 loop	Reference Identification	Optional	>1
`N9`	Reference Identification	Mandatory	1
`DTM`	Date/Time Reference	Optional	>1
`MSG`	Message Text	Optional	>1
N1 loop	Name	Optional	10
`N1`	Name	Mandatory	1
`N2`	Additional Name Information	Optional	2
`N3`	Address Information	Optional	2
`N4`	Geographic Location	Optional	1
`NX2`	Location ID Component	Optional	>1
`REF`	Reference Identification	Optional	12
`PER`	Administrative Communications Contact	Optional	3
`SI`	Service Characteristic Identification	Optional	>1
CTT loop	Transaction Totals	Optional	1
`CTT`	Transaction Totals	Mandatory	1
`AMT`	Monetary Amount	Optional	1
`SE`	Transaction Set Trailer	Mandatory	1

Mandatory segments must be sent, Optional ones only when the data applies. Trading partners often add their own rules in companion guides - ediFabric templates can be adjusted to match. Open the element-level definition in the EdiNation spec library.

Sample 855 file

An acknowledgment of a purchase order with line-level status. Paste it into EdiNation to see every element named and validated.

ISA*00*          *00*          *16*SENDER1        *14*RECEIVER1      *071216*1406*U*00204*000000263*1*T*>~
GS*IN*SENDER1*RECEIVER1*20071216*1406*000000001*X*004010~
ST*855*0005~
BAK*16*AP*1234567*20050102~
DTM*068*20050203~
N1*SF*XYZ MANUFACTURING CO*01*987654321~
N1*ST*KOHLS DEPARTMENT STORES*92*0085~
PO1*000001*3*EA***UP*123456789012*VA*BLU89Z012*CM*123*SM*12345~
PO1*000002*5*EA***UP*123456798123*VA*BLK98A023*CM*321*SM*12345~
PO1*000003*1*EA***UP*999988888001*VA*981RACK~
CTT*3~
SE*10*0005~
GE*2*000000001~
IEA*1*000000263~

The same 855 as JSON

ediFabric turns every loop, segment and element into a named field. This is the transaction from the sample, in the JSON that ediFabric Native and Cloud return and accept.

{
  "ST": {
    "TransactionSetIdentifierCode_01": "855",
    "TransactionSetControlNumber_02": "0005"
  },
  "BAK": {
    "TransactionSetPurposeCode_01": "16",
    "AcknowledgmentType_02": "AP",
    "PurchaseOrderNumber_03": "1234567",
    "Date_04": "20050102"
  },
  "DTM": [
    {
      "DateTimeQualifier_01": "068",
      "Date_02": "20050203"
    }
  ],
  "N1Loop": [
    {
      "N1": {
        "EntityIdentifierCode_01": "SF",
        "Name_02": "XYZ MANUFACTURING CO",
        "IdentificationCodeQualifier_03": "01",
        "IdentificationCode_04": "987654321"
      }
    },
    {
      "N1": {
        "EntityIdentifierCode_01": "ST",
        "Name_02": "KOHLS DEPARTMENT STORES",
        "IdentificationCodeQualifier_03": "92",
        "IdentificationCode_04": "0085"
      }
    }
  ],
  "PO1Loop": [
    {
      "PO1": {
        "AssignedIdentification_01": "000001",
        "QuantityOrdered_02": "3",
        "UnitorBasisforMeasurementCode_03": "EA",
        "ProductServiceIDQualifier_06": "UP",
        "ProductServiceID_07": "123456789012",
        "ProductServiceIDQualifier_08": "VA",
        "ProductServiceID_09": "BLU89Z012",
        "ProductServiceIDQualifier_10": "CM",
        "ProductServiceID_11": "123",
        "ProductServiceIDQualifier_12": "SM",
        "ProductServiceID_13": "12345"
      }
    },
    {
      "PO1": {
        "AssignedIdentification_01": "000002",
        "QuantityOrdered_02": "5",
        "UnitorBasisforMeasurementCode_03": "EA",
        "ProductServiceIDQualifier_06": "UP",
        "ProductServiceID_07": "123456798123",
        "ProductServiceIDQualifier_08": "VA",
        "ProductServiceID_09": "BLK98A023",
        "ProductServiceIDQualifier_10": "CM",
        "ProductServiceID_11": "321",
        "ProductServiceIDQualifier_12": "SM",
        "ProductServiceID_13": "12345"
      }
    },
    {
      "PO1": {
        "AssignedIdentification_01": "000003",
        "QuantityOrdered_02": "1",
        "UnitorBasisforMeasurementCode_03": "EA",
        "ProductServiceIDQualifier_06": "UP",
        "ProductServiceID_07": "999988888001",
        "ProductServiceIDQualifier_08": "VA",
        "ProductServiceID_09": "981RACK"
      }
    }
  ],
  "CTTLoop": {
    "CTT": {
      "NumberofLineItems_01": "3"
    }
  },
  "SE": {
    "NumberofIncludedSegments_01": "10",
    "TransactionSetControlNumber_02": "0005"
  }
}

Parse and validate an 855 file

Read the file into typed objects with ediFabric .NET, convert it to JSON in process with the ediFabric Native bindings for Python, Java and C, or post it to the ediFabric Cloud REST API from any language.

.NET
Python
Java
C
Cloud

using EdiFabric.Templates.X12004010;

License.SetSerial("YOUR_SERIAL_KEY");

using (var stream = File.OpenRead(@"C:\edi\PurchaseOrdersAcknowledgement.txt"))
using (var reader = new X12Reader(stream, "EdiFabric.Templates.X12"))
{
    var items = await reader.ReadToEndAsync();
    foreach (var transaction in items.OfType<TS855>())
    {
        if (transaction.IsValid(out MessageErrorContext errors))
            Console.WriteLine($"{transaction.ST.TransactionSetControlNumber_02} is valid");
        else
            Console.WriteLine(string.Join(Environment.NewLine, errors.Flatten()));
    }
} Install and get started 855 example project Walkthrough
import json
import edifabric_x12 as ef

serial = "YOUR_SERIAL_KEY"
ef.load_library()
ef.set_serial(serial)
ef.set_map(json.dumps({"default": serial, "maps": {}}))

edi = open("PurchaseOrdersAcknowledgement.txt", "rb").read()
output, offset = ef.parse(edi, ef.ParseMode.JSON_VALIDATE)
transactions = output[:offset]
report = json.loads(output[offset:])
print(report["errors_count"]) Python bindingsediFabric Native
import com.edifabric.nativex12.EdiFabricX12;
import com.edifabric.nativex12.ParseMode;
import com.edifabric.nativex12.ParseResult;

String serial = "YOUR_SERIAL_KEY";
EdiFabricX12.loadLibrary();
EdiFabricX12.setSerial(serial);
EdiFabricX12.setMap("{\"default\":\"" + serial + "\",\"maps\":{}}");

String edi = Files.readString(Path.of("PurchaseOrdersAcknowledgement.txt"));
ParseResult result = EdiFabricX12.parse(edi, ParseMode.JSON_VALIDATE);
System.out.println(result.getTransactions());
System.out.println(result.getReport()); Java bindingsediFabric Native
#include "edifabric_x12.h"

const char *serial = "YOUR_SERIAL_KEY";
ef_parse_result result;

if (ef_load_library(NULL) != 0)
    return 1;
ef_set_serial(serial);
ef_set_map("{\"default\":\"YOUR_SERIAL_KEY\",\"maps\":{}}");

char *edi = read_file("PurchaseOrdersAcknowledgement.txt", NULL);   /* helper in example_all_functions.c */
if (ef_parse(edi, EF_PARSE_JSON_VALIDATE, NULL, &result) == 0) {
    /* transactions = output[0 .. offset), report = output[offset .. length) */
    fwrite(result.output.data, 1, (size_t)result.output.length, stdout);
    ef_free(result.output.data);
} C bindingsediFabric Native
curl -X POST 'https://api.edination.com/v2/x12/read' \
-H 'Ocp-Apim-Subscription-Key: YOUR_SERIAL_KEY' \
-H 'Content-Type: application/octet-stream' \
--data-binary '@PurchaseOrdersAcknowledgement.txt' TranslateValidateediFabric Cloud

Generate an 855 file

Populate a TS855 object in .NET, or pass JSON in the shape shown above to ediFabric Native or ediFabric Cloud, and get a valid 855 file back.

.NET
Python
Java
C
Cloud

using EdiFabric.Templates.X12004010;

License.SetSerial("YOUR_SERIAL_KEY");

var transaction = new TS855();

//  855 is the Transaction Set Identifier Code for the Purchase Orders Acknowledgement
//  0001 is the Transaction Set Control Number
transaction.ST = new ST();
transaction.ST.TransactionSetIdentifierCode_01 = "855";
transaction.ST.TransactionSetControlNumber_02 = "0001";


//  Purchase Order Number 1234567
//  Purchase Order Date 01 / 02 / 05            
transaction.BAK = new BAK();
transaction.BAK.TransactionSetPurposeCode_01 = "16";
transaction.BAK.AcknowledgmentType_02 = "AP";
transaction.BAK.PurchaseOrderNumber_03 = "1234567";
transaction.BAK.Date_04 = "20050102";

//  Repeating DTM
transaction.DTM = new List<DTM>();

// ... set the remaining loops and segments the same way

// SegmentBuilders is in the Common project of the example repository
using (var stream = new MemoryStream())
{
    using (var writer = new X12Writer(stream))
    {
        writer.Write(SegmentBuilders.BuildIsa("1"));
        writer.Write(SegmentBuilders.BuildGs("1"));
        writer.Write(transaction);
    }
    Console.WriteLine(Encoding.UTF8.GetString(stream.ToArray()));
} Install and get started Full 855 build methodExample repository
import json
import edifabric_x12 as ef

serial = "YOUR_SERIAL_KEY"
ef.load_library()
ef.set_serial(serial)
ef.set_map(json.dumps({"default": serial, "maps": {}}))

# the transactions JSON returned by ef.parse, edited or produced by your application
transactions = open("PurchaseOrdersAcknowledgement.json", "rb").read()
edi = ef.build(transactions, postfix="\r\n")
print(edi) Python bindings
import com.edifabric.nativex12.EdiFabricX12;

String serial = "YOUR_SERIAL_KEY";
EdiFabricX12.loadLibrary();
EdiFabricX12.setSerial(serial);
EdiFabricX12.setMap("{\"default\":\"" + serial + "\",\"maps\":{}}");

// the transactions JSON returned by parse, edited or produced by your application
String transactions = Files.readString(Path.of("PurchaseOrdersAcknowledgement.json"));
String edi = EdiFabricX12.build(transactions, "\r\n");
System.out.println(edi); Java bindings
#include "edifabric_x12.h"

ef_buffer edi;

if (ef_load_library(NULL) != 0)
    return 1;
ef_set_serial("YOUR_SERIAL_KEY");
ef_set_map("{\"default\":\"YOUR_SERIAL_KEY\",\"maps\":{}}");

/* the transactions JSON returned by ef_parse, edited or produced by your application */
char *transactions = read_file("PurchaseOrdersAcknowledgement.json", NULL);
if (ef_build(transactions, "\r\n", &edi) == 0) {
    fwrite(edi.data, 1, (size_t)edi.length, stdout);
    ef_free(edi.data);
} C bindings
# the JSON returned by /read, edited or produced by your application
curl -X POST 'https://api.edination.com/v2/x12/write' \
-H 'Ocp-Apim-Subscription-Key: YOUR_SERIAL_KEY' \
-H 'Content-Type: application/json' \
--data-binary '@PurchaseOrdersAcknowledgement.json' \
-o 'PurchaseOrdersAcknowledgement.txt' How-tosediFabric Cloud

855 questions

What do the BAK02 codes mean?

AC acknowledge with detail and change, AD acknowledge with detail and no change, AK acknowledge with no detail or change, RJ rejected with no detail. Trading partners usually allow a subset.

How are line changes reported?

With ACK segments in the PO1 loop. ACK01 is the line status, such as IA accepted, IB backordered, IC changed or IR rejected, with the quantity and date in the following elements.

Is the 855 the same as a 997?

No. The 997 only confirms that the 850 was received and is syntactically valid. The 855 is a business response about the order itself.

How do I parse and generate X12 855 files in .NET, Python, Java and C?

In .NET, install EdiFabric and EdiFabric.Templates.X12, read the file with X12Reader into TS855 objects and write them back with X12Writer. From Python, Java or C, use ediFabric Native, which converts 855 files to JSON and JSON back to X12 inside your process. From any other language, post the file to the ediFabric Cloud REST API.

Related transactions

X12 850 - Purchase Order
X12 856 - Ship Notice/Manifest (ASN)
EANCOM ORDRSP - Purchase Order Response
All EDI transactions →

X12 855 Purchase Order Acknowledgment

At a glance