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What is an implementation guide

When you and your trading partner decide to exchange business documents, you’ll need to agree on a data format. The implementation guide describes that data format. It’s essentially a schema definition, but it comes with a few peculiarities that are specific to EDI.

The implementation guide is known under many other names. For example, you may run into the term companion guide, or EDI reference guide, or even just guide. It all means the same. In our documentation, we stick with implementation guide.

Base specification

An implementation guide is based on a base specification. There is a base specification for each type of transaction set. For example, there’s one for invoices, one for health care claims, one for ship notices, etc.

The base specification is designed to be generic. The base specification for ship notices has fields for every type of ship notice you could ever encounter. In day-to-day use, that is far too generic. You and your trading partner can come to an agreement on what a ship notice should look like and then adjust the base specification to include only the fields that are relevant to the both of you. The result is an implementation guide.

Base specifications are standardized. There are several EDI standards. The most common are X12 and EDIFACT.

  • See also: List of all X12 transaction sets
  • See also: List of all EDIFACT transaction sets
An example of a transaction set
The transaction set describes all possible segments.
An example of an implementation guide
An implementation guide has only a subset of all the segments. There can be other differences as well. For example, some segments that are optional in the transaction set are mandatory in the implementation guide.


An implementation guide includes information like expected fields, data types and sizes, and which fields are required. You can use this to validate all incoming and outgoing EDI documents.


In a lot of cases, the data you receive is not in the exact format you need. For example, you receive an invoice with the billing address split into street address, zip code, and city, but your internal system needs it in a single field. Or your warehouse management system produces order information with internal codes for package sizes, but EDI uses different codes. You’ll have to transform the input shape into the desired output shape. This is called mapping.

An implementation guide is a big help when defining the mapping, because it accurately describes the data shape.

Machine-readable guides

Typically, you receive an implementation guide from your trading partner as a PDF document. That’s easy to read for us humans, but a computer can’t use it to do validation and mapping for you. With Stedi Guides, you can translate the PDF into a machine-readable implementation guide and use it to generate EDI.

Base specificationValidationMappingMachine-readable guides