What is an HL7 v2 message?

HL7 v2 is a pipe-delimited text format used by healthcare systems to exchange clinical and administrative data. Each message is made up of segments (MSH, PID, OBX, etc.), with fields separated by | and sub-parts by ^.

Does hl7online.com send my HL7 messages to a server?

No. Parsing and validation run entirely in your browser — the raw HL7 message never leaves your device. Only when you ask the optional AI assistant a question is the parsed (and optionally anonymized) data sent to our backend.

Which HL7 versions and message types are supported?

HL7 v2.3 through v2.8, including ORU, ADT, ORM, SIU, MDM, DFT, VXU, ACK, and others. Z-segments and unknown segments are displayed rather than rejected.

Is hl7online.com HIPAA compliant?

The tool is built with a privacy-focused architecture — raw messages are parsed client-side, PHI can be anonymized before AI queries, and no PHI is stored. However, hl7online.com is not currently offered under a Business Associate Agreement (BAA) and is not a HIPAA-certified service. Do not paste unredacted PHI when querying AI unless your organization approves.

HL7 Online — Free HL7 v2 Message Parser & AI Assistant

VimByte

AI-Powered Healthcare Integration

hl7online.com is an independent, free tool built by Nick Davies — a very senior engineer at a health AI company, with years of hands-on experience building HL7 interfaces for clinical laboratories and hospital information systems. This is a personal project: it is not affiliated with, sponsored by, or endorsed by his employer.

After years of watching integration analysts squint at raw pipe-delimited text and lab managers escalate tickets just to decode a message, I built the tool I wish I'd had — and made it free for the healthcare integration and point-of-care testing community. hl7online.com combines instant client-side parsing with AI-powered natural language queries, all designed around privacy.

Why free?

The people who need this tool — integration analysts, lab staff, POCT coordinators — usually can't push a purchase order through just to decode a message. So there's no paywall, no subscription, and no ads. A free account is all you need for the AI assistant; parsing never requires one.

Let's talk

Have an integration challenge? Building something with AI in healthcare? Found a bug or want a feature? I'd love to hear about it.

nick.davies@vimbyte.com Work with Nick →

Documentation

Everything you need to know about hl7online.com

Three steps to decode any HL7 message:

1

Paste

Paste your HL7 message into the editor

2

Parse

Instant parsing and validation right in your browser

3

Ask AI

Ask questions in plain English and get instant answers

Tip: Click Load Sample to try it out with a pre-loaded lab result message.

A privacy-first architecture with local parsing and edge AI.

Your Browser

HL7 Parser (JavaScript)
Message Validator
Syntax Highlighting
PHI Anonymization

All parsing stays local

AI queries only

Edge Server

Local AI Model
Authentication
No cloud dependencies

Privacy-focused architecture

HL7 v2.x messages are pipe-delimited text. Here is the anatomy of a message:

Message Header (MSH Segment)

MSH|^~\&|LabSystem|Hospital|EHR|Clinic|20260323120000||ORU^R01|MSG00001|P|2.5.1

Segment ID

Encoding Characters

Field Separator

Field Values

Key Concepts

Segments

Each line is a segment starting with a 3-letter ID: MSH, PID, OBR, OBX, etc.

Fields

Segments are divided into fields by the pipe | character. Each field has a defined meaning.

Components

Fields can contain sub-parts separated by ^ (caret). Example: ORU^R01 = type + trigger.

Common Messages

ORU = results, ORM = orders, ADT = admissions, ACK = acknowledgments.

The HL7 Assistant understands HL7 messages and can answer natural language questions. Try these:

Note: AI requires a connection to the edge server. The parsing and validation work entirely offline.

HL7 v2 Message Parser

Paste a message to see it decoded