Offline Mode
Parse and validate HL7 messages without a network connection
Cache an HL7 version schema locally for parsing in air-gapped environments.
Offline mode automatically caches the compact schema for each HL7 version you load so you can parse and validate messages without reaching the API server. This is designed for air-gapped environments, unreliable connections, or faster startup when working with a known version.
How to Enable
Open Settings
Open Settings from the parser sidebar (Settings) or the gear icon in any pane's header, then find the "Offline Mode" group in the General section. You can also toggle offline mode directly with the cloud button in the parser toolbar.
Load the Version While Online
Select the HL7 version you need in the parser toolbar. The compact schema (segments, data types, tables with their values, and message structures) is downloaded and stored in localStorage automatically the first time that version loads. Each version you use gets its own cache entry.
Toggle Offline
Enable offline mode. The parser switches to the cached schema and stops making API requests.
What Works Offline
Message Parsing
Full HL7 v2 message parsing with segment tree and field navigation.
Schema Validation
Validate required fields, data types, lengths, cardinality, and table references against the cached schema.
Syntax Highlighting
Editor syntax highlighting and theme colors work without changes.
Field Details
Segment, field, and component names, data type definitions, and table values (codes and display names) from the cached schema. Specification documentation text and field descriptions are unavailable offline.
What Requires a Connection
Terminology Validation
Code lookups against the terminology server (LOINC, SNOMED, etc.) require a network connection.
Cross-Version Search
Searching across all 14 versions requires the API.
FHIR & CDA Resources
FHIR package loading and CDA template browsing require the API.
Specification Docs
Rendered specification chapters and documentation text are served by the API.
The cached schema is invalidated when the application updates its schema format. Re-download the schema after updates while connected.
Schemas are cached automatically, one entry per version. Every version you load while online stays available offline, and you can switch between cached versions without a connection. Each cached schema is small: roughly 50 KB (v2.1) to 530 KB (v2.9).