Premium tool

HL7 Message Diff

Compare two HL7 v2 messages: segment order, segment counts and field values, with added, removed and changed parts highlighted.

Textual comparison only. This tool shows where the text of two messages differs. It does not decide whether they mean the same thing, so equal text is not proof of equivalence and different text is not proof of a real difference. Repeated segments (such as OBX) are compared by occurrence. Messages are processed in memory on the server and are not stored or logged. Use synthetic or de-identified messages only.

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Message A (before)

Message B (after)

How repeated segments are paired

Aligned mode copes better with an inserted or removed OBX but is a heuristic: it pairs segments only when at least half of their non-empty fields match.

Ignore paths Proposed Pro plan

One per line: a field (MSH-7), a component (PID-5.2) or a whole segment (NTE). Ignored differences are hidden but counted. Enforced on the server.

Choose Compare messages to see the differences.

Segment counts

Number of segments by ID in each message
Segment	Message A	Message B	Difference

Show Include unchanged segments

Parse warnings