Upcoming: Standard delimiters in X12 eligibility responses

In the coming weeks, Stedi will normalize all X12 271 eligibility responses to use a standard set of delimiters.

If you do not parse the raw X12 271 and only parse Stedi's JSON response, this change will not impact you.

What are X12 delimiters?
In X12, delimiters are characters that separate the parts of a transaction set. Each transaction set has four types of delimiters:

• Element Separator – Separates fields

• Repetition Separator – Separates repeat values

• Component Element Separator – Separates sub-elements

• Segment Terminator – Ends each segment

These delimiters are defined in the ISA segment and can vary across transaction sets.

How it works today
Stedi currently passes through whatever X12 delimiters the payer sends.

However, some payers use unsafe characters, such as carriage returns, as delimiters in their 271 eligibility responses. This can break X12 parsing for some Stedi customers.

What’s changing
Stedi will normalize all delimiters returned in X12 271 eligibility responses to the following characters:

• Element Separator: * 

• Repetition Separator: ^

• Component Element Separator: >

• Segment Terminator: ~

If any of the above delimiters appear in a data element value – meaning the delimiter isn’t used to delimit content but is used as content – we will replace it as follows:

For example:

O*CONNOR → O|CONNOR
CODE^01 → CODE|01
O`CONNOR → O'CONNOR
MSG~HELLO → MSG|HELLO

What’s impacted
This change will affect all X12 271 eligibility responses returned by Stedi, including those returned by the:

• X12 Eligibility API endpoint

• SOAP Eligibility API endpoint

• x12 property of our JSON Eligibility API endpoint

• x12 field of our Poll Batch Eligibility Checks endpoint

• Stedi portal

Next steps
If you do not parse the raw X12 271 and only parse Stedi's JSON response, this will not impact you. Most Stedi customers won’t need to make any changes for this update. 

However, if your X12 parser assumes fixed delimiters instead of reading them from the ISA segment, you should confirm that your parser will continue to work after the update.

If you need time to update your parsing logic or have questions, contact us using your dedicated support channel or our contact form by December 22, 2025.