diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 00cb14b..6eb7975 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,3 +25,15 @@ jobs:
       - uses: actions/checkout@v4
       - run: cargo test
       - run: cargo test --features ffi
+
+  wasm:
+    name: WASM
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+      - uses: jetli/wasm-pack-action@v0.4.0
+      - run: rustup target add wasm32-unknown-unknown
+      - run: npm run wasm:ci
diff --git a/.github/workflows/npm-publish.yml b/.github/workflows/npm-publish.yml
new file mode 100644
index 0000000..ae4ebcc
--- /dev/null
+++ b/.github/workflows/npm-publish.yml
@@ -0,0 +1,27 @@
+name: Publish WASM Package
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          registry-url: "https://registry.npmjs.org"
+
+      - uses: jetli/wasm-pack-action@v0.4.0
+
+      - run: rustup target add wasm32-unknown-unknown
+      - run: npm run wasm:ci
+      - run: npm run wasm:publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
diff --git a/.gitignore b/.gitignore
index ea8c4bf..30fa6c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,4 @@
 /target
+/pkg
+/pkg-node
+/pkg-web
diff --git a/Cargo.lock b/Cargo.lock
index 9bf9c1a..dcdc0ff 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -35,12 +35,28 @@ version = "2.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "812e12b5285cc515a9c72a5c1d3b6d46a19dac5acfef5265968c166106e31dd3"
 
+[[package]]
+name = "bumpalo"
+version = "3.20.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "console_error_panic_hook"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a06aeb73f470f66dcdbf7223caeebb85984942f22f1adb2a088cf9668146bbbc"
+dependencies = [
+ "cfg-if",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -321,6 +337,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
+
 [[package]]
 name = "rusty-fork"
 version = "0.3.1"
@@ -409,8 +431,10 @@ dependencies = [
 name = "text-processing-rs"
 version = "0.1.0"
 dependencies = [
+ "console_error_panic_hook",
  "lazy_static",
  "proptest",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -458,6 +482,51 @@ dependencies = [
  "wit-bindgen",
 ]
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.114"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6532f9a5c1ece3798cb1c2cfdba640b9b3ba884f5db45973a6f442510a87d38e"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+ "rustversion",
+ "wasm-bindgen-macro",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.114"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18a2d50fcf105fb33bb15f00e7a77b772945a2ee45dcf454961fd843e74c18e6"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.114"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "03ce4caeaac547cdf713d280eda22a730824dd11e6b8c3ca9e42247b25c631e3"
+dependencies = [
+ "bumpalo",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.114"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75a326b8c223ee17883a4251907455a2431acc2791c98c26279376490c378c16"
+dependencies = [
+ "unicode-ident",
+]
+
 [[package]]
 name = "wasm-encoder"
 version = "0.244.0"
diff --git a/Cargo.toml b/Cargo.toml
index f918537..cde6772 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,6 +13,8 @@ crate-type = ["lib", "staticlib", "cdylib"]
 
 [dependencies]
 lazy_static = "1"
+wasm-bindgen = { version = "0.2", optional = true }
+console_error_panic_hook = { version = "0.1", optional = true }
 
 [dev-dependencies]
 proptest = "1"
@@ -20,3 +22,4 @@ proptest = "1"
 [features]
 default = []
 ffi = []  # Enable C FFI bindings
+wasm = ["dep:wasm-bindgen", "dep:console_error_panic_hook"]
diff --git a/README.md b/README.md
index 130372e..dfd23e0 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,62 @@ let result = tn_normalize("123");
 assert_eq!(result, "one hundred twenty three");
 ```
 
+### JavaScript (WASM)
+
+Build wasm artifacts:
+
+```bash
+npm run wasm:build:node
+npm run wasm:build:web
+```
+
+Node usage:
+
+```javascript
+import * as wasm from "./pkg-node/text_processing_rs.js";
+
+console.log(wasm.normalize("two hundred")); // "200"
+console.log(wasm.tnNormalize("$5.50")); // "five dollars and fifty cents"
+
+wasm.addRule("gee pee tee", "GPT");
+console.log(wasm.normalize("gee pee tee")); // "GPT"
+```
+
+The generated npm package name is `@fluidinference/text-processing-rs`.
+
+Web project usage (Vite / Next.js / webpack):
+
+```bash
+npm install @fluidinference/text-processing-rs
+```
+
+```javascript
+import init, * as wasm from "@fluidinference/text-processing-rs";
+
+async function run() {
+  // Loads and initializes the .wasm module (required once at startup)
+  await init();
+
+  const itn = wasm.normalize("two hundred");
+  const tn = wasm.tnNormalize("$5.50");
+
+  console.log(itn); // "200"
+  console.log(tn); // "five dollars and fifty cents"
+
+  wasm.addRule("gee pee tee", "GPT");
+  console.log(wasm.normalize("gee pee tee")); // "GPT"
+}
+
+run();
+```
+
+If your framework supports top-level `await`, you can initialize at module load time:
+
+```javascript
+import init, * as wasm from "@fluidinference/text-processing-rs";
+await init();
+```
+
 Sentence-level normalization scans for normalizable spans within a larger sentence:
 
 ```rust
@@ -163,6 +219,19 @@ cargo build
 cargo test
 ```
 
+### WASM + JavaScript
+
+```bash
+# Build + smoke test (Node) + build browser artifact
+npm run wasm:ci
+
+# Create a tarball from the browser package
+npm run wasm:pack
+
+# Publish browser package to npm (requires npm auth)
+npm run wasm:publish
+```
+
 ### CLI Tools
 
 ```bash
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..4ac5a1a
--- /dev/null
+++ b/package.json
@@ -0,0 +1,22 @@
+{
+  "name": "@fluidinference/text-processing-rs",
+  "version": "0.1.0",
+  "description": "Inverse Text Normalization (ITN) — convert spoken-form ASR output to written form",
+  "type": "module",
+  "main": "pkg-web/text_processing_rs.js",
+  "types": "pkg-web/text_processing_rs.d.ts",
+  "files": [
+    "pkg-web/text_processing_rs.js",
+    "pkg-web/text_processing_rs.d.ts",
+    "pkg-web/text_processing_rs_bg.wasm",
+    "pkg-web/text_processing_rs_bg.wasm.d.ts"
+  ],
+  "scripts": {
+    "wasm:build:node": "wasm-pack build --release --target nodejs --features wasm && mkdir -p pkg-node && cp -f pkg/* pkg-node/ && node scripts/set-wasm-package-name.mjs pkg-node",
+    "wasm:build:web": "wasm-pack build --release --target web --features wasm && mkdir -p pkg-web && cp -f pkg/* pkg-web/ && node scripts/set-wasm-package-name.mjs pkg-web",
+    "wasm:test:node": "node wasm-tests/node-smoke.mjs",
+    "wasm:ci": "npm run wasm:build:node && npm run wasm:test:node && npm run wasm:build:web",
+    "wasm:pack": "npm pack ./pkg-web",
+    "wasm:publish": "npm publish ./pkg-web --access public"
+  }
+}
diff --git a/scripts/set-wasm-package-name.mjs b/scripts/set-wasm-package-name.mjs
new file mode 100644
index 0000000..fa1b6ab
--- /dev/null
+++ b/scripts/set-wasm-package-name.mjs
@@ -0,0 +1,13 @@
+import fs from 'node:fs';
+import path from 'node:path';
+
+const pkgDir = process.argv[2];
+if (!pkgDir) {
+  throw new Error('Usage: node scripts/set-wasm-package-name.mjs <pkg-dir>');
+}
+
+const packageJsonPath = path.join(pkgDir, 'package.json');
+const pkg = JSON.parse(fs.readFileSync(packageJsonPath, 'utf8'));
+pkg.name = '@fluidinference/text-processing-rs';
+pkg.keywords = ['asr', 'speech', 'normalization', 'nlp', 'itn', 'tts', 'wasm'];
+fs.writeFileSync(packageJsonPath, `${JSON.stringify(pkg, null, 2)}\n`);
diff --git a/src/lib.rs b/src/lib.rs
index 493997a..5ad114d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,6 +22,8 @@ pub mod tn;
 
 #[cfg(feature = "ffi")]
 pub mod ffi;
+#[cfg(all(target_arch = "wasm32", feature = "wasm"))]
+pub mod wasm;
 
 use itn::en::{
     cardinal, date, decimal, electronic, measure, money, ordinal, punctuation, telephone, time,
diff --git a/src/wasm.rs b/src/wasm.rs
new file mode 100644
index 0000000..0ccfd04
--- /dev/null
+++ b/src/wasm.rs
@@ -0,0 +1,90 @@
+//! WebAssembly exports for JavaScript interop.
+
+use wasm_bindgen::prelude::*;
+
+use crate::{
+    custom_rules, normalize, normalize_sentence, normalize_sentence_with_max_span,
+    normalize_with_lang, tn_normalize, tn_normalize_lang, tn_normalize_sentence,
+    tn_normalize_sentence_lang, tn_normalize_sentence_with_max_span,
+    tn_normalize_sentence_with_max_span_lang,
+};
+
+/// Initialize panic hook for better error messages in browser devtools.
+#[wasm_bindgen]
+pub fn set_panic_hook() {
+    console_error_panic_hook::set_once();
+}
+
+#[wasm_bindgen(js_name = normalize)]
+pub fn normalize_js(input: &str) -> String {
+    normalize(input)
+}
+
+#[wasm_bindgen(js_name = normalizeWithLang)]
+pub fn normalize_with_lang_js(input: &str, lang: &str) -> String {
+    normalize_with_lang(input, lang)
+}
+
+#[wasm_bindgen(js_name = normalizeSentence)]
+pub fn normalize_sentence_js(input: &str) -> String {
+    normalize_sentence(input)
+}
+
+#[wasm_bindgen(js_name = normalizeSentenceWithMaxSpan)]
+pub fn normalize_sentence_with_max_span_js(input: &str, max_span_tokens: u32) -> String {
+    normalize_sentence_with_max_span(input, max_span_tokens as usize)
+}
+
+#[wasm_bindgen(js_name = tnNormalize)]
+pub fn tn_normalize_js(input: &str) -> String {
+    tn_normalize(input)
+}
+
+#[wasm_bindgen(js_name = tnNormalizeLang)]
+pub fn tn_normalize_lang_js(input: &str, lang: &str) -> String {
+    tn_normalize_lang(input, lang)
+}
+
+#[wasm_bindgen(js_name = tnNormalizeSentence)]
+pub fn tn_normalize_sentence_js(input: &str) -> String {
+    tn_normalize_sentence(input)
+}
+
+#[wasm_bindgen(js_name = tnNormalizeSentenceLang)]
+pub fn tn_normalize_sentence_lang_js(input: &str, lang: &str) -> String {
+    tn_normalize_sentence_lang(input, lang)
+}
+
+#[wasm_bindgen(js_name = tnNormalizeSentenceWithMaxSpan)]
+pub fn tn_normalize_sentence_with_max_span_js(input: &str, max_span_tokens: u32) -> String {
+    tn_normalize_sentence_with_max_span(input, max_span_tokens as usize)
+}
+
+#[wasm_bindgen(js_name = tnNormalizeSentenceWithMaxSpanLang)]
+pub fn tn_normalize_sentence_with_max_span_lang_js(
+    input: &str,
+    lang: &str,
+    max_span_tokens: u32,
+) -> String {
+    tn_normalize_sentence_with_max_span_lang(input, lang, max_span_tokens as usize)
+}
+
+#[wasm_bindgen(js_name = addRule)]
+pub fn add_rule_js(spoken: &str, written: &str) {
+    custom_rules::add_rule(spoken, written);
+}
+
+#[wasm_bindgen(js_name = removeRule)]
+pub fn remove_rule_js(spoken: &str) -> bool {
+    custom_rules::remove_rule(spoken)
+}
+
+#[wasm_bindgen(js_name = clearRules)]
+pub fn clear_rules_js() {
+    custom_rules::clear_rules();
+}
+
+#[wasm_bindgen(js_name = ruleCount)]
+pub fn rule_count_js() -> u32 {
+    custom_rules::rule_count() as u32
+}
diff --git a/wasm-tests/node-smoke.mjs b/wasm-tests/node-smoke.mjs
new file mode 100644
index 0000000..d59a2dc
--- /dev/null
+++ b/wasm-tests/node-smoke.mjs
@@ -0,0 +1,42 @@
+import * as wasm from '../pkg-node/text_processing_rs.js';
+
+function assertEqual(actual, expected, message) {
+  if (actual !== expected) {
+    throw new Error(`${message}: expected "${expected}", got "${actual}"`);
+  }
+}
+
+function assertTrue(condition, message) {
+  if (!condition) {
+    throw new Error(message);
+  }
+}
+
+assertEqual(wasm.normalize('two hundred'), '200', 'normalize should convert spoken numbers');
+assertEqual(
+  wasm.normalizeWithLang('two hundred', 'en'),
+  '200',
+  'normalizeWithLang should work'
+);
+assertEqual(
+  wasm.normalizeSentence('I have twenty one apples'),
+  'I have 21 apples',
+  'normalizeSentence should convert spans'
+);
+assertEqual(wasm.tnNormalize('$5.50'), 'five dollars and fifty cents', 'tnNormalize should work');
+assertEqual(
+  wasm.tnNormalizeSentence('I paid $5 for 23 items'),
+  'I paid five dollars for twenty three items',
+  'tnNormalizeSentence should convert spans'
+);
+
+wasm.clearRules();
+assertEqual(wasm.ruleCount(), 0, 'ruleCount starts at 0');
+wasm.addRule('gee pee tee', 'GPT');
+assertEqual(wasm.ruleCount(), 1, 'ruleCount increments');
+assertEqual(wasm.normalize('gee pee tee'), 'GPT', 'custom rules should apply');
+assertTrue(wasm.removeRule('gee pee tee'), 'removeRule should return true when found');
+assertEqual(wasm.ruleCount(), 0, 'rule removed');
+assertTrue(!wasm.removeRule('gee pee tee'), 'removeRule should return false when missing');
+
+console.log('WASM node smoke test passed');