HL7 v2 → FHIR R4 · INTERACTIVE MAPPING EXPLORER

Paste an HL7 v2 message. See exactly how it maps to FHIR.

A real parser — delimiters read from MSH-1 and MSH-2 rather than assumed, MSH indices reconstructed, repetitions and subcomponents decomposed properly. It shows the mapping decision for every field, the FHIR Bundle it produces, and the places it deliberately refuses to guess.

Segment reference
Learning and specification tool — not an interface engine. Paste de-identified or synthetic messages only. Nothing you paste leaves your browser, but the discipline matters more than the mechanism.
Built by Kalilur Rahman29 years in enterprise and regulated healthcare IT, leading integration-heavy delivery across India GCCs. The mapping notes reflect what actually breaks in production interfaces, not what the spec says in the happy path.
Explorer

Your message, decomposed

Paste a message or load a sample. Everything is parsed and mapped in your browser — no upload, no storage, no network call.

Sample messages
HL7 v2 message
Segments may be separated by CR, LF or CRLF. Custom delimiters are detected automatically from MSH-1/MSH-2.

Your parse appears here

Load a sample and hit parse. Free gives you the full parser, the FHIR Bundle, the mapping table and every finding — the whole tool, not a teaser.

Reference

Segment reference

The segments you actually meet, what each field carries, and where it lands in FHIR. Click a segment to expand.

Message types

The trigger events that make up most real traffic.
TypeNameWhat it meansUsual segments
The field guide

What breaks in production

The parser and mappings are free. What costs money is knowing which of these decisions will page you at 3am — the failure modes you only learn by shipping interfaces in hospitals.

Regulated environments

Qualifying the interface

An interface moving GxP or patient data is a computerised system, and needs the same qualification evidence as any other. This is the part generic integration guidance omits — and the part an auditor asks about first.

Regression suite

The hostile message pack

Messages that naive parsers handle wrongly, each paired with the behaviour a correct implementation must show. Three are loaded in the explorer free — try them. The full pack with expected behaviours is a regression suite you can run against your own engine or a vendor's.

Migration

Putting FHIR in front of a v2 estate

Most v2-to-FHIR programmes fail the same way, and it is rarely technical. The playbook covers the sequencing, the measurement that decides your timeline, and the risk that derails each phase.

Pricing

Free tool. Paid judgement.

Free

$0
  • Full HL7 v2 parser, custom delimiters and all
  • FHIR R4 Bundle generation + JSON export
  • Field-by-field mapping table
  • Complete segment & message-type reference
  • All parse findings and warnings
  • Production failure-mode guide
  • Per-field integration notes

Field Guide

$49 one-time
  • Everything in Free
  • Production failure modes — what actually breaks and why
  • Per-field integration notes inline in the explorer
  • Mapping specification export you can hand to a vendor
  • Interface IQ/OQ/PQ + ALCOA+ for data in transit
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  • 12-case regression pack with expected behaviours
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  • v2→FHIR migration playbook
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  • AI review prompt for your own mapping spec
  • Lifetime on this device
Get the Field Guide — $49

Integration advisory

Let's talk
  • Interface strategy & vendor conformance review
  • Migration planning: v2 estate → FHIR
  • Regulated-environment integration governance
  • Engagement — roadmap
Enquire
FAQ

Straight answers

Is my message uploaded anywhere?

No. There is no backend. Parsing, mapping and export all happen in your browser — you can disconnect from the network and it still works. That said, paste de-identified or synthetic messages: good habits around PHI shouldn't depend on trusting a web page.

Can I use this as an interface engine?

No, and please don't. It doesn't validate against FHIR profiles, doesn't do terminology translation against a real code-system server, doesn't persist or transmit anything, and has no error handling or retry semantics. It's a tool for understanding mappings and writing specifications, which is a different job.

Whose mapping is this?

One defensible reading of the standard, chosen to be explicit about ambiguity rather than confident about guesses. Where a value has no clean FHIR equivalent, the tool says so instead of inventing one. Your trading partner's conformance profile always overrides a general-purpose default.

Which HL7 versions does it handle?

The parser is version-agnostic because it reads delimiters and structure from the message itself. The field reference targets the 2.3.1 through 2.5.1 range, which is what the overwhelming majority of production interfaces still run.

I already have a code.

Enter it here — it unlocks the field guide and inline notes on this device.

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