X12 Envelope Validator
ISA/IEA, GS/GE and ST/SE nesting, control numbers and counts for any X12 transaction type.
Clinical safety notice: Zero real patient data (PHI/PII) may be entered into this browser utility. Use synthetic test payloads only. Local-first deterministic processing; nothing leaves your browser.
How it works
The ISA must be 106 characters with the element separator at the 16 fixed positions. Field checks: ISA01 and ISA03 are 00 or 01; ISA02 and ISA04 are 10 characters; ISA06 and ISA08 are 15; ISA09 is a YYMMDD date; ISA10 HHMM; ISA12 five digits; ISA13 nine digits; ISA14 is 0 or 1; ISA15 is P, T or I. GS04 must be a CCYYMMDD date and GS06 numeric. Structure: every ISA needs a matching IEA with the same ISA13/IEA02 and IEA01 equal to the number of groups; every GS a GE with GS06 equal to GE02 and GE01 equal to the number of transaction sets; every ST an SE with ST02 equal to SE02 and SE01 equal to the segment count from ST to SE inclusive. Trailers that are missing, out of order or unmatched are errors. Content inside transactions is not checked.
Operational disclaimer. Results reflect deterministic parsing of user-provided datasets; verify against institutional standards and regulatory frameworks.
Deterministic local--first client-side execution; data transmission is zero. Provided as-is without warranty under the 1% value-saved licensing model.