Langium is a toolkit for building DSLs with modern editor support

A TypeScript framework for creating domain-specific-languages. Define grammar, get parsing, validation, and Language Server Protocol integration.

The value: LSP support means your custom language works in VS Code, Monaco, and other editors—autocomplete, diagnostics, go-to-definition—without building each feature manually.

Built on the shoulders of Xtext (Eclipse ecosystem) but TypeScript-native and web-friendly.

See also: dygram