How to Parse HL7 Messages and Convert to FHIR R4 Programmatically

How to Parse HL7 Messages and Convert to FHIR R4 Programmatically HL7 v2 is the most widely used healthcare messaging standard in the world. Despite being decades old, it still carries the majority of clinical data between hospitals, labs, pharmacies, and EHR systems. If you have ever opened a raw HL7 message, you know the problem immediately: it is a pipe-delimited wall of text with no labels, no hierarchy, and no obvious way to extract the data you need. This article explains what HL7 v2 messages look like, why parsing them is harder than it appears, and how to parse and convert them programmatically using a free tool and MCP server. What makes HL7 v2 hard to parse An HL7 v2 message looks something like this: MSH|^~\&|EPIC|HOSPITAL|LAB|LAB|20260316120000||ADT^A01|MSG00001|P|2.5 EVN|A01|20260316120000 PID|1||MRN12345^^^HOSPITAL^MR||DOE^JOHN^A||19800115|M|||123 MAIN ST^^DALLAS^TX^75201 PV1|1|I|ICU^101^A|E|||1234567890^SMITH^ROBERT^J^^^MD|5678901234^JONES^MARY^L^^^MD NK1|1|DOE^JANE|SPO|