HL7 v2 Message Parser

About this tool

Paste an HL7 v2.x message and get a structured breakdown of its segments, fields, components, subcomponents, and repetitions. The parser reads the field separator and encoding characters from the MSH segment, handles the special MSH-1 / MSH-2 offset, and can attach human-readable names for common segments and fields such as MSH, PID, PV1, OBR, and OBX.

Use JSON when you want the full hierarchy, including repetitions and nested components. Use CSV when you want a flat table of non-empty leaf values with locations like PID.5.1 or OBX.5. The tool runs locally in your browser, so the message text is not uploaded.

Worked example

Input:

MSH|^~\&|SENDINGAPP|SENDINGFAC|RECVAPP|RECVFAC|20240101120000||ADT^A01|MSG00001|P|2.5
EVN|A01|20240101120000
PID|1||123456^^^HOSPITAL^MR||DOE^JOHN^Q||19800101|M

With output json, descriptions enabled, and HL7 unescaping enabled, the output is a JSON array whose first object is the MSH segment. MSH.9 is split into components ADT and A01, and PID.5 is labeled Patient Name with components DOE, JOHN, and Q.

With output csv, the same message becomes rows like:

Segment,Location,Value,Description
MSH,MSH.9.1,ADT,Message Type
MSH,MSH.9.2,A01,Message Type
PID,PID.5.1,DOE,Patient Name
PID,PID.5.2,JOHN,Patient Name

Limits and edge cases

• This is a parser/viewer, not a validator against a complete HL7 conformance profile.
• Field descriptions are curated for common segments. Unknown fields still parse, but may not have a description label.
• Segment separators may be carriage returns, line feeds, or CRLF.
• HL7 escape decoding covers \F\, \S\, \T\, \R\, \E\, \Xhh\, and \.br\; turn Decode HL7 escape sequences off to preserve raw values.
• Output is text (JSON or CSV). The tool does not convert HL7 to FHIR or edit and re-serialize messages.