diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5ddd776..2884123 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,11 +23,14 @@ jobs:
     steps:
       - uses: actions/checkout@v7
       - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/setup-node@v6
         with:
-          targets: wasm32-unknown-unknown
-      - run: cargo install wasm-bindgen-cli --version 0.2.128
+          node-version: '24'
+      - run: npm install
       - run: npm run build
         working-directory: wasm
+      - run: npm test
+        working-directory: wasm
 
   build:
     needs: test
diff --git a/DEV.md b/DEV.md
index 1b67bd2..03e013d 100644
--- a/DEV.md
+++ b/DEV.md
@@ -40,14 +40,19 @@ The repository is a Cargo workspace with one published crate and one binding cra
 
 `wasm/` is `mdhtml-wasm`, the `wasm-bindgen` glue for the browser, and `wasm/package.json` is the npm package `@answerdotai/mdhtml` around it. The package is private until its first publish. Its `version` field is a copy that `ship-bump` keeps in step through `[tool.fastship].version-files`.
 
-Building needs two one-time installs. The CLI version must match the crate version pinned in `wasm/Cargo.toml`.
+WASM builds require Rust managed by rustup and Node/npm. The project's npm dependency `wasm-pack` installs the WASM target when missing and downloads or builds the CLI matching Cargo's resolved `wasm-bindgen` version. No separate target or CLI installation is needed.
+
+In an aai-ws workspace, `ws-sync` installs the npm dependencies, links local packages, and runs the WASM build. For a standalone checkout, install and build from the repository root:
 
 ```bash
-rustup target add wasm32-unknown-unknown
-cargo install wasm-bindgen-cli --version 0.2.128
+npm install
+npm run build --workspace wasm
+npm test --workspace wasm
 ```
 
-`npm run build` in `wasm/` compiles with the `wasm` profile (`dist` at `opt-level = "z"`, for size) and runs `wasm-bindgen` into the ignored `wasm/pkg/`: the `.wasm`, the JavaScript glue, and type declarations. That is the `maturin develop` of the JavaScript side. In the browser the output of `md2mdhtml` goes straight into the DOM, and the browser's own parser does the tree construction that fast5ever does for Python.
+`npm run build` in `wasm/` compiles with the `wasm` profile (`dist` at `opt-level = "z"`, for size) and generates the ignored `wasm/pkg/`: the `.wasm`, the JavaScript glue, and type declarations. It keeps the hand-maintained npm manifest and does not run an additional wasm-opt pass. That is the `maturin develop` of the JavaScript side. In the browser the output of `md2mdhtml` goes straight into the DOM, and the browser's own parser does the tree construction that fast5ever does for Python.
+
+`npm test` in `wasm/` runs Node's built-in test runner against that generated browser-targeted package, checking rendering and Unicode string transfer through the real WASM module. Build first after Rust changes; the test does not rebuild. CI installs, builds, and tests through the same npm commands.
 
 A binding crate can only reach the library's public surface, so anything a binding needs is exported from `src/lib.rs`. The Python glue needs six items beyond the documented API (`render_inlines`, `plain`, `code_block_open`, `CODE_BLOCK_CLOSE`, `trailing_attr_span`, `highlight_md`), exported by name so the modules that hold them stay private.
 
diff --git a/wasm/Cargo.toml b/wasm/Cargo.toml
index 3fb48bd..6509b1c 100644
--- a/wasm/Cargo.toml
+++ b/wasm/Cargo.toml
@@ -15,4 +15,4 @@ crate-type = ["cdylib"]
 
 [dependencies]
 mdhtml-crate = { path = ".." }
-wasm-bindgen = "=0.2.128"
+wasm-bindgen = ">=0.2.128"
diff --git a/wasm/package.json b/wasm/package.json
index ab35009..665a1b2 100644
--- a/wasm/package.json
+++ b/wasm/package.json
@@ -9,7 +9,11 @@
 	"main": "pkg/mdhtml_wasm.js",
 	"types": "pkg/mdhtml_wasm.d.ts",
 	"files": ["pkg"],
+	"devDependencies": {
+		"wasm-pack": ">=0.15.0"
+	},
 	"scripts": {
-		"build": "cargo build -p mdhtml-wasm --target wasm32-unknown-unknown --profile wasm && wasm-bindgen --target web --out-dir pkg ../target/wasm32-unknown-unknown/wasm/mdhtml_wasm.wasm"
+		"build": "wasm-pack build --target web --profile wasm --no-pack --no-opt",
+		"test": "node --test test.js"
 	}
 }
diff --git a/wasm/test.js b/wasm/test.js
new file mode 100644
index 0000000..3c9b9c8
--- /dev/null
+++ b/wasm/test.js
@@ -0,0 +1,17 @@
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import test from 'node:test';
+import init, { md2mdhtml } from '@answerdotai/mdhtml';
+
+await init({ module_or_path: readFileSync(new URL('./pkg/mdhtml_wasm_bg.wasm', import.meta.url)) });
+
+test('renders Markdown through the generated JavaScript bindings', () => {
+    assert.equal(md2mdhtml('# Hello\n\n**world**'), '<h1>Hello</h1>\n<p><strong>world</strong></p>\n');
+    assert.equal(md2mdhtml(''), '');
+});
+
+test('preserves Unicode across repeated calls and memory growth', () => {
+    for (const text of ['café 日本語 🦀', '🦀'.repeat(100000), 'café 日本語 🦀']) {
+        assert.equal(md2mdhtml(text), `<p>${text}</p>\n`);
+    }
+});