Gleam v1.13.0 introduces formalized external APIs for JavaScript interop, allowing safer integration with external code through dedicated functions for constructing and accessing Gleam data types. The release includes significant compiler improvements: enhanced bit array exhaustiveness checking with interference-based pruning, unused argument detection in recursive functions, and better fault-tolerant analysis. The language server gains multiple new code actions including extract function, collapse nested cases, and pattern matching helpers. Additional improvements include better error messages for common syntax mistakes from other languages, dependency version change notifications, and enhanced type display in documentation.