v4.3.0

• Added support for upcoming WebAssembly proposals (Phase 2–3). The compiler implements them correctly; runtime testing awaits V8 shipping full support.
• Custom Descriptors (Phase 3) — descriptor/describes type clauses, exact heap types, struct.new_desc, struct.new_default_desc, ref.get_desc, ref.cast_desc_eq, br_on_cast_desc_eq, br_on_cast_desc_eq_fail
• Stack Switching (Phase 3) — cont composite type, cont/nocont heap types, cont.new, cont.bind, suspend, resume, resume_throw, resume_throw_ref, switch
• Custom Page Sizes (Phase 3) — (pagesize N) attribute on memory declarations
• Compact Import Section (Phase 3) — grouped (import "mod" (item "name" type)*) syntax, expanded to individual imports
• WAT Numeric Values (Phase 2) — i8/i16/i32/i64/f32/f64 typed values in data segments

Official test suite updated to 2026-03-25. All passing tests continue to pass.

Full Changelog: v4.2.1...v4.3.0

v4.2.0

• polyfill option
• optimize option

Full Changelog: v4.0.0...v4.2.0

v4.0.0

• Spec-complete with GC, exception handling, all proposals
• Streamlined & simplified mnemonics engine
• watr tagged template for instant wasm exports
• Auto-import JS functions via second argument
• Interpolate values, BigInts, typed arrays, memory
• CLI: npx watr input.wat -o output.wasm

Full Changelog: v3.3.0...v4.0.0

v3.2.1

Faster, smaller & more reliable.

Full Changelog: v3.0.0...v3.2.1

v3.0.0

What's Changed

• Complete standard text syntax support
• Official testsuite
• Feature: v128
• Feature: function refs
• Feature: reference types
• Feature: multiple memories / tables
• Fix: proper indexes
• Optimization: streamlined compiler

Full Changelog: v2.0.0...v3.0.0

v2.0

• Added full support for inline / stacked code
• Added code formatter for pretty/min-print
• Reduced code size & increased performance