free · in-browser · no upload

HL7 to JSON
Converter

Drop your HL7 v2 file. We'll convert it to JSON right here in your browser, your file never leaves your device.

or drop your file

Select your file here to get started

or drop your file here.

Accepts .hl7, .txt

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

1
Drop your file
Click the dropzone above or drag a HL7 v2 from your desktop. Files of any size, there's no upload, so there's no upload limit.
2
Convert in your browser
The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.
3
Download
Get your JSON the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Drop a file, get a converted file.

Why convert HL7 → JSON

What this conversion is actually for

HL7 v2 → JSON is the first step of every modernization project — feeding legacy v2 feeds into a FHIR server, a data warehouse (Snowflake/Databricks/BigQuery), or a no-code automation platform. The structural translation is mechanical (segment.field.component path), but writing it by hand is error-prone for the first time. The JSON output is keyed by segment type with `MSH.10`-style field paths so downstream code can address fields without re-parsing pipes.

A real example

You're building a ML pipeline that flags admissions with elevated readmission risk. Your input is a stream of ADT^A01 messages from your interface engine. Convert each to JSON, drop into your feature store, train. The JSON keys (`PID.5`, `PV1.10`, `DG1.3`) are stable across messages so your feature extraction code doesn't break.

Troubleshooting

Component values are sometimes strings, sometimes arrays.

When a field has a single component (just a value), we emit a string. When it has multiple components (e.g. `DOE^JOHN^A`), we emit an array `['DOE', 'JOHN', 'A']`. Code that consumes the JSON should normalize: `Array.isArray(v) ? v : [v]`.

Repeated fields are nested arrays — how do I flatten?

HL7 allows tilde-separated repetitions in a single field (multiple addresses, multiple insurance IDs). When repetitions exist, the value is an array of components-arrays. Most of the time you only care about the first repetition: `Array.isArray(v[0]) ? v[0] : v`.

Formats involved

About HL7 v2 and JSON

HL7 v2, Health Level 7 version 2.x messaging

HL7 v2 is the universal messaging standard between U.S. hospital systems — Epic, Cerner, Meditech, Allscripts, Athena all speak it for ADT (admit/discharge/transfer), ORU (observation results), ORM (orders), and billing messages. Format dates to 1989; v2.5 (2003) is the most-deployed version. Pipe-delimited segments with caret-separated components and tilde-separated repetitions; the MSH header carries encoding characters and routing metadata. Despite FHIR's modern push, v2 still powers the operational backbone of most hospital networks.

How to open

Any text editor — HL7 v2 is plain text with `|`/`^`/`~` as delimiters. Specialized viewers (Mirth Connect, Iguana, NextGen Connect, IBM Sterling) parse + index segments. For programmatic use, libraries exist for every language (HAPI in Java/.NET, hl7v2-js in Node).

Full HL7 v2 format guide →

JSON, JavaScript Object Notation

JSON is a lightweight text format for structured data, nested objects, arrays, strings, numbers, booleans. It's the lingua franca of web APIs, configuration files, and data interchange between programs. Human-readable when formatted, machine-parseable in every programming language, and roughly half the size of equivalent XML.

How to open

Any text editor reads JSON. Browsers display .json files in a formatted tree view. VS Code and similar editors highlight syntax.

Full JSON format guide →

Related tools

Convert other files to JSON

Convert your HL7 v2 to other formats

HL7 v2 → CSV

FAQ

Common questions

Is this HL7 → JSON converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert HL7 v2 to JSON?

Hospital-to-hospital and intra-hospital clinical messaging. API responses, configuration files, structured data interchange. The most common reason to convert is compatibility, JSON works in places where HL7 v2 doesn't, or vice versa.

How do I open a HL7 v2 file in the first place?

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.

HL7 to JSONConverter