HL7 language support for Visual Studio Code
Syntax highlighting, field tokenization, and hover info for HL7 v2.x messages in Visual Studio Code.
Field definitions and hover info use the HL7 v2.5.1 and v2.7.1 data dictionaries (auto-detected from MSH-12). Messages from other v2.x versions will still get syntax highlighting, but field names and datatypes may not match exactly.
Features
Syntax coloring
- Segments and field separators are highlighted for easy interpretation.
Field Hover Info
- Hover over any field in an HL7 message to see its name, datatype, and component breakdown.
- For fields with multiple components (separated by
^), all components are listed with the one under the cursor highlighted.
Field Level Highlighting
- Place your cursor on any segment name (e.g.,
OBX) to highlight every occurrence
of that segment across the message.
- Place your cursor on a field or component to highlight the same field path on all
matching segment lines — useful for comparing values like
OBX-5 across multiple
observations or PID-5.2 (Given Name) across patient records.
Tokenize Line Command
- Move the cursor to a line that you wish to tokenize.
- F1 -> HL7: Tokenize Line
- Line will be split into fields with the ordinal and definition.
- Output opens in a dedicated tab (starting from the top) that is reused on subsequent tokenize actions.
Auto-Tokenize Mode
- F1 -> HL7: Toggle Auto-Tokenize
- When enabled, the current line is automatically tokenized as you move the cursor through the file — no need to re-run the command for each line.
- A status bar indicator shows when Auto-Tokenize is active. Click it to toggle off.
Filter Segment Command
- Move the cursor to a line that you wish to filter.
- F1 -> HL7: Filter Segment
- A new file will be created containing only segments that match the current line.
Copy Field Path
- Place the cursor on any field or component in an HL7 message.
- Right-click -> HL7: Copy Field Path (or F1 -> HL7: Copy Field Path)
- Copies the HL7 path (e.g.
PID-3.1 or PID-1) to the clipboard.
MLLP Send & Receive
- Send Message: F1 -> HL7: Send Message — sends the current file (or selection) to an MLLP endpoint and displays the ACK response.
- Start Listener: F1 -> HL7: Start MLLP Listener — starts a local MLLP server that receives messages and opens each one in a new editor tab.
- Stop Listener: F1 -> HL7: Stop MLLP Listener — stops the running listener.
- Default host and port are configurable via
hl7.mllp.host and hl7.mllp.port settings.
Segment Count & Version Status Bar
- The status bar displays the detected HL7 version and a count of segments in the current file (e.g.
HL7 v2.7.1 | 12 segments (5 types)).
- Hover over it to see a breakdown by segment type.
- Right-click in an HL7 file to access Filter Segment, Tokenize Line, and Copy Field Path directly from the context menu.
Commands
| Command |
Description |
HL7: Tokenize Line |
Split the current line into fields with ordinals and definitions |
HL7: Toggle Auto-Tokenize |
Automatically tokenize each line as the cursor moves |
HL7: Filter Segment |
Create a new file containing only matching segment types |
HL7: Copy Field Path |
Copy the HL7 field path at the cursor to the clipboard |
HL7: Send Message |
Send the current message to an MLLP endpoint |
HL7: Start MLLP Listener |
Start a local MLLP listener to receive messages |
HL7: Stop MLLP Listener |
Stop the running MLLP listener |
Installation
Visual Studio Code
Search for "HL7" in the Extensions sidebar, or press F1 and enter ext install pbrooks.hl7.
Manual Installation
Clone the GitHub repository under your local extensions folder:
- Windows:
%USERPROFILE%\.vscode\extensions
- Mac / Linux:
$HOME/.vscode/extensions
Then initialize the repository submodules:
git submodule init
git submodule update
Issues / Feature requests
You can submit your issues and feature requests on the GitHub issues page.
Support This Project
If this extension is useful to you, consider sponsoring its development.
What is HL7?
HL7 (Health Level Seven) is a set of standards for exchanging clinical and administrative data between healthcare systems. The v2.x messaging format uses pipe-delimited segments (e.g. MSH, PID, OBR) and is one of the most widely deployed healthcare integration standards in the world.
