diff --git a/.mise.toml b/.mise.toml
index bb64685..a3b91c7 100644
--- a/.mise.toml
+++ b/.mise.toml
@@ -6,6 +6,7 @@ cmake = "latest"
 dprint = "latest"
 editorconfig-checker = "latest"
 "github:block/goose" = "latest"
+"github:wasm-bindgen/wasm-bindgen" = "0.2.114"
 ollama = "latest"
 osv-scanner = "latest"
 pipx = "latest"
@@ -68,7 +69,11 @@ run = "cargo run"
 [tasks.build-ws-wasm-agent]
 description = "Build the WebSocket WASM client"
 dir = "services/ws-wasm-agent"
-run = "wasm-pack build --target web"
+run = "wasm-pack build . --target web -- -Z build-std=std,panic_abort"
+
+[tasks.build-ws-wasm-agent.env]
+RUSTFLAGS = "-C target-cpu=mvp -C target-feature=+mutable-globals,+sign-ext,+nontrapping-fptoint"
+RUSTUP_TOOLCHAIN = "nightly"
 
 [tasks.test-ws-wasm-agent-firefox]
 description = "Run headless Firefox tests for the WebSocket WASM client"
diff --git a/README.md b/README.md
index fd164c9..57531f3 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,8 @@ mise run build-ws-wasm-agent
 mise run ws-server
 ```
 
+The WASM build disables WebAssembly reference types so it can still load on older browsers such as Chrome 95.
+
 Find the IP address of your laptop in the local network,
 which will normally be something like 192.168.1.x.
 
diff --git a/services/ws-server/static/app.js b/services/ws-server/static/app.js
index 8a4f0b3..3caa152 100644
--- a/services/ws-server/static/app.js
+++ b/services/ws-server/static/app.js
@@ -131,6 +131,33 @@ const formatNumber = (value, digits = 3) => (
   Number.isFinite(value) ? value.toFixed(digits) : "n/a"
 );
 
+const configureOnnxRuntimeWasm = () => {
+  if (!window.ort?.env?.wasm) {
+    throw new Error("onnxruntime-web environment is unavailable.");
+  }
+
+  const ortVersion = window.ort.env.versions?.web;
+  if (typeof ortVersion !== "string" || ortVersion.length === 0) {
+    throw new Error("onnxruntime-web version is unavailable.");
+  }
+
+  const distBaseUrl = `https://cdn.jsdelivr.net/npm/onnxruntime-web@${ortVersion}/dist`;
+  const supportsWasmThreads = window.crossOriginIsolated === true
+    && typeof SharedArrayBuffer !== "undefined";
+
+  window.ort.env.wasm.numThreads = supportsWasmThreads ? 0 : 1;
+  window.ort.env.wasm.wasmPaths = {
+    mjs: `${distBaseUrl}/ort-wasm-simd-threaded.mjs`,
+    wasm: `${distBaseUrl}/ort-wasm-simd-threaded.wasm`,
+  };
+
+  append(
+    `onnxruntime-web configured: version=${ortVersion} wasm=${window.ort.env.wasm.wasmPaths.wasm} threads=${
+      window.ort.env.wasm.numThreads === 1 ? "disabled" : "auto"
+    }`,
+  );
+};
+
 const degreesToRadians = (value) => (
   Number.isFinite(value) ? (value * Math.PI) / 180 : 0
 );
@@ -797,6 +824,8 @@ try {
         throw new Error("onnxruntime-web did not load.");
       }
 
+      configureOnnxRuntimeWasm();
+
       harButton.disabled = true;
       harButton.textContent = "Loading HAR...";
       updateHarStatus(["loading model..."]);