diff --git a/src-tauri/tauri.conf.json b/src-tauri/tauri.conf.json
index 57e1e57..e37ab6e 100644
--- a/src-tauri/tauri.conf.json
+++ b/src-tauri/tauri.conf.json
@@ -23,7 +23,7 @@
       }
     ],
     "security": {
-      "csp": "default-src 'self'; script-src 'self' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; font-src 'self' data:; connect-src ipc: http://ipc.localhost https://open.er-api.com https://api.coingecko.com https://query1.finance.yahoo.com https://query2.finance.yahoo.com https://api.frankfurter.dev"
+      "csp": "default-src 'self'; script-src 'self' blob:; style-src 'self'; img-src 'self' data:; font-src 'self' data:; connect-src ipc: http://ipc.localhost https://open.er-api.com https://api.coingecko.com https://query1.finance.yahoo.com https://query2.finance.yahoo.com https://api.frankfurter.dev"
     }
   },
   "bundle": {
diff --git a/src/extensions.test.ts b/src/extensions.test.ts
index 41691ec..c5113ba 100644
--- a/src/extensions.test.ts
+++ b/src/extensions.test.ts
@@ -40,14 +40,37 @@ describe("extensions", () => {
     let consoleErrorSpy: any;
 
     beforeEach(() => {
+      vi.stubGlobal("window", { __numi_api: undefined });
+      vi.stubGlobal("Blob", class Blob {
+        parts: any[];
+        options: any;
+        constructor(parts: any[], options: any) { this.parts = parts; this.options = options; }
+      });
+      vi.stubGlobal("URL", {
+        createObjectURL: vi.fn((blob: any) => "blob:" + blob.parts[0]),
+        revokeObjectURL: vi.fn()
+      });
+      vi.stubGlobal("document", {
+        createElement: vi.fn(() => ({ src: "", onload: null, onerror: null })),
+        head: { appendChild: vi.fn((script: any) => {
+          try {
+            const code = script.src.replace(/^blob:/, "");
+            eval(code);
+            if (script.onload) script.onload();
+          } catch(e) {
+            if (script.onerror) script.onerror();
+          }
+        }) }
+      });
       consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
     });
 
     afterEach(() => {
+      vi.unstubAllGlobals();
       consoleErrorSpy.mockRestore();
     });
 
-    it("runs scripts successfully using numi api", () => {
+    it("runs scripts successfully using numi api", async () => {
       const scripts = [
         {
           name: "script1",
@@ -59,14 +82,14 @@ describe("extensions", () => {
         },
       ];
 
-      runExtensions(mockEngine as SumEngine, scripts);
+      await runExtensions(mockEngine as SumEngine, scripts);
 
       expect(mockEngine.setVariable).toHaveBeenCalledWith("var1", 10);
       expect(mockEngine.addUnit).toHaveBeenCalledWith({ id: "unit1", phrases: "u", baseUnitId: "USD", ratio: 1 });
       expect(consoleErrorSpy).not.toHaveBeenCalled();
     });
 
-    it("swallows errors and logs to console.error", () => {
+    it("swallows errors and logs to console.error", async () => {
       const scripts = [
         {
           name: "script1",
@@ -74,7 +97,7 @@ describe("extensions", () => {
         },
       ];
 
-      runExtensions(mockEngine as SumEngine, scripts);
+      await runExtensions(mockEngine as SumEngine, scripts);
 
       expect(consoleErrorSpy).toHaveBeenCalledWith(
         "extension script1 failed:",
@@ -82,7 +105,7 @@ describe("extensions", () => {
       );
     });
 
-    it("continues running other scripts if one fails", () => {
+    it("continues running other scripts if one fails", async () => {
       const scripts = [
         {
           name: "script1",
@@ -98,7 +121,7 @@ describe("extensions", () => {
         },
       ];
 
-      runExtensions(mockEngine as SumEngine, scripts);
+      await runExtensions(mockEngine as SumEngine, scripts);
 
       expect(mockEngine.setVariable).toHaveBeenCalledWith("var1", 10);
       expect(mockEngine.setVariable).toHaveBeenCalledWith("var3", 30);
diff --git a/src/extensions.ts b/src/extensions.ts
index 73967ad..5848e5e 100644
--- a/src/extensions.ts
+++ b/src/extensions.ts
@@ -16,14 +16,32 @@ export function makeApi(engine: SumEngine): ExtensionApi {
   };
 }
 
-export function runExtensions(engine: SumEngine, scripts: { name: string; code: string }[]): void {
+export async function runExtensions(engine: SumEngine, scripts: { name: string; code: string }[]): Promise<void> {
   const numi = makeApi(engine);
+  (window as any).__numi_api = numi;
   for (const s of scripts) {
-    try {
-      const fn = new Function("numi", s.code);
-      fn(numi);
-    } catch (e) {
-      console.error(`extension ${s.name} failed:`, e);
-    }
+    await new Promise<void>((resolve) => {
+      try {
+        const wrappedCode = `try { (function(numi) { ${s.code} })(window.__numi_api); } catch(e) { window.__numi_err = e; }`;
+        const blob = new Blob([wrappedCode], { type: "text/javascript" });
+        const url = URL.createObjectURL(blob);
+        const script = document.createElement("script");
+        script.src = url;
+        script.onload = () => {
+          URL.revokeObjectURL(url);
+          if ((window as any).__numi_err) {
+            console.error(`extension ${s.name} failed:`, (window as any).__numi_err);
+            delete (window as any).__numi_err;
+          }
+          resolve();
+        };
+        script.onerror = () => { URL.revokeObjectURL(url); resolve(); };
+        document.head.appendChild(script);
+      } catch (e) {
+        console.error(`extension ${s.name} failed:`, e);
+        resolve();
+      }
+    });
   }
+  delete (window as any).__numi_api;
 }
diff --git a/src/main.ts b/src/main.ts
index d0bedf1..6f9d85d 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -745,7 +745,7 @@ async function initDataAndEngine(): Promise<void> {
   if (!data.docs.some((d) => d.id === data.activeId)) data.activeId = data.docs[0].id;
 
   const scripts = await loadExtensionScripts();
-  runExtensions(engine, scripts);
+  await runExtensions(engine, scripts);
 
   workspace = new Workspace(engine, () =>
     data.docs.map((d) => ({ id: d.id, title: d.title, text: data.contents[d.id] ?? "" })),