diff --git a/.github/workflows/wasi-bindings.yml b/.github/workflows/wasi-bindings.yml
new file mode 100644
index 00000000000..8bc5142e16e
--- /dev/null
+++ b/.github/workflows/wasi-bindings.yml
@@ -0,0 +1,43 @@
+name: WASI Bindings
+
+on:
+  push:
+    paths:
+      - ".github/workflows/wasi-bindings.yml"
+      - "include/"
+      - "src/"
+      - "*akefile*"
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: head
+          bundler-cache: true
+
+      - name: rake templates
+        run: bundle exec rake templates
+
+      - name: Create build directory
+        run: mkdir -p build
+
+      - name: Set up WASI-SDK
+        run: |
+          wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-20/wasi-sdk-20.0-linux.tar.gz
+          tar xvf wasi-sdk-20.0-linux.tar.gz
+
+      - name: Build the project
+        run: make wasm WASI_SDK_PATH=$(pwd)/wasi-sdk-20.0
+
+      - uses: actions/upload-artifact@v3
+        with:
+          name: prism.wasm
+          path: build/prism.wasm
diff --git a/Makefile b/Makefile
index 8e1c4b20d47..d64d968656f 100644
--- a/Makefile
+++ b/Makefile
@@ -13,6 +13,7 @@ SOEXT := $(shell ruby -e 'puts RbConfig::CONFIG["SOEXT"]')
 CPPFLAGS := -Iinclude
 CFLAGS := -g -O2 -std=c99 -Wall -Werror -Wextra -Wpedantic -Wundef -Wconversion -fPIC -fvisibility=hidden
 CC := cc
+WASI_SDK_PATH := /opt/wasi-sdk
 
 HEADERS := $(shell find include -name '*.h')
 SOURCES := $(shell find src -name '*.c')
@@ -23,6 +24,7 @@ all: shared static
 
 shared: build/librubyparser.$(SOEXT)
 static: build/librubyparser.a
+wasm: build/prism.wasm
 
 build/librubyparser.$(SOEXT): $(SHARED_OBJECTS)
 	$(ECHO) "linking $@"
@@ -32,6 +34,10 @@ build/librubyparser.a: $(STATIC_OBJECTS)
 	$(ECHO) "building $@"
 	$(Q) $(AR) $(ARFLAGS) $@ $(STATIC_OBJECTS) $(Q1:0=>/dev/null)
 
+build/prism.wasm: Makefile $(SOURCES) $(HEADERS)
+	$(ECHO) "building $@"
+	$(Q) $(WASI_SDK_PATH)/bin/clang --sysroot=$(WASI_SDK_PATH)/share/wasi-sysroot/ $(DEBUG_FLAGS) -DPRISM_EXPORT_SYMBOLS -D_WASI_EMULATED_MMAN -lwasi-emulated-mman $(CPPFLAGS) $(CFLAGS) -Wl,--export-all -Wl,--no-entry -mexec-model=reactor -o $@ $(SOURCES)
+
 build/shared/%.o: src/%.c Makefile $(HEADERS)
 	$(ECHO) "compiling $@"
 	$(Q) mkdir -p $(@D)
diff --git a/templates/src/serialize.c.erb b/templates/src/serialize.c.erb
index e985e72ec38..9528496c7df 100644
--- a/templates/src/serialize.c.erb
+++ b/templates/src/serialize.c.erb
@@ -150,11 +150,11 @@ static void
 pm_serialize_magic_comment(pm_parser_t *parser, pm_magic_comment_t *magic_comment, pm_buffer_t *buffer) {
     // serialize key location
     pm_buffer_append_u32(buffer, pm_ptrdifft_to_u32(magic_comment->key_start - parser->start));
-    pm_buffer_append_u32(buffer, pm_ptrdifft_to_u32(magic_comment->key_length));
+    pm_buffer_append_u32(buffer, pm_sizet_to_u32(magic_comment->key_length));
 
     // serialize value location
     pm_buffer_append_u32(buffer, pm_ptrdifft_to_u32(magic_comment->value_start - parser->start));
-    pm_buffer_append_u32(buffer, pm_ptrdifft_to_u32(magic_comment->value_length));
+    pm_buffer_append_u32(buffer, pm_sizet_to_u32(magic_comment->value_length));
 }
 
 static void