diff --git a/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/index.ts b/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/index.ts
index 61bfaba..8acd927 100644
--- a/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/index.ts
+++ b/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/index.ts
@@ -57,8 +57,8 @@ if (!inSharedWorker()) {
     );
   };
 
-  // Just check fetch is blocked on registration, don't slow down message processing.
-  rpc.receive("registerScript", enforceFetchIsBlocked(registerScript));
+  // Allow fetch in user scripts at runtime by removing the CSP wrapper:
+  rpc.receive("registerScript", registerScript);
   rpc.receive("processMessage", processMessage);
 
   port.start();
diff --git a/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/registry.ts b/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/registry.ts
index 6be5354..be42bf6 100644
--- a/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/registry.ts
+++ b/packages/suite-base/src/players/UserScriptPlayer/runtimeWorker/registry.ts
@@ -135,13 +135,13 @@ export const registerScript = ({
   }
 };
 
-export const processMessage = ({
+export const processMessage = async ({
   message,
   globalVariables,
 }: {
   message: unknown;
   globalVariables: GlobalVariables;
-}): ProcessMessageOutput => {
+}): Promise<ProcessMessageOutput> => {
   const userScriptLogs: UserScriptLog[] = [];
   const userScriptDiagnostics: Diagnostic[] = [];
   (self as { log?: unknown }).log = function (...args: unknown[]) {
@@ -157,8 +157,12 @@ export const processMessage = ({
     userScriptLogs.push(...args.map((value) => ({ source: "processMessage" as const, value })));
   };
   try {
-    const newMessage = nodeCallback(message, globalVariables);
-    return { message: newMessage, error: undefined, userScriptLogs, userScriptDiagnostics };
+    // Invoke the user script; if it's async, await its completion
+    const result = await (async () => {
+      const r = nodeCallback(message, globalVariables);
+      return Promise.resolve(r);
+    })();
+    return { message: result, error: undefined, userScriptLogs, userScriptDiagnostics };
   } catch (err) {
     const error: string = err.toString();
     const diagnostic: Diagnostic = {
diff --git a/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/index.ts b/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/index.ts
index 0719edd..09b06e2 100644
--- a/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/index.ts
+++ b/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/index.ts
@@ -69,7 +69,7 @@ if (!inSharedWorker()) {
   rpc.receive("close", () => {
     global.close();
   });
-  rpc.receive("transform", enforceFetchIsBlocked(transform));
+  rpc.receive("transform", transform);
   rpc.receive("generateRosLib", generateRosLib);
   port.start();
 };
diff --git a/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/ast.ts b/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/ast.ts
index b96078a..32872ae 100644
--- a/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/ast.ts
+++ b/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/ast.ts
@@ -200,8 +200,12 @@ export const findReturnType = (
     throw new DatatypeExtractionError(nonFuncError);
   }
 
+  // Determine the actual return type, unwrapping Promise<T> if needed
   const fullReturnType = typeChecker.getReturnTypeOfSignature(signature);
-  const nonNullable = fullReturnType.getNonNullableType();
+  // If it's a Promise, get the promised inner type; otherwise use as-is
+  const unwrappedType =
+    typeChecker.getPromisedTypeOfPromise(fullReturnType) ?? fullReturnType;
+  const nonNullable = unwrappedType.getNonNullableType();
 
   // In some future we could support intersection types where all the fields are known
   if (nonNullable.isIntersection()) {
diff --git a/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/lib.ts b/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/lib.ts
index 2a9e985..480bdca 100644
--- a/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/lib.ts
+++ b/packages/suite-base/src/players/UserScriptPlayer/transformerWorker/typescript/lib.ts
@@ -61,6 +61,8 @@ import lib_es2022_regexp from "typescript/lib/lib.es2022.regexp.d.ts?raw";
 import lib_es2022_sharedmemory from "typescript/lib/lib.es2022.sharedmemory.d.ts?raw";
 import lib_es2022_string from "typescript/lib/lib.es2022.string.d.ts?raw";
 import lib_es5_dts from "typescript/lib/lib.es5.d.ts?raw";
+import lib_dom_dts from "typescript/lib/lib.dom.d.ts?raw";
+import lib_dom_iterable_dts from "typescript/lib/lib.dom.iterable.d.ts?raw";
 
 export const lib_filename = "lib.d.ts";
 
@@ -147,5 +149,7 @@ function resolveReferences(originalSrc: string): string {
   });
 }
 
-const resolvedDts = resolveReferences(lib_es2022_dts);
-export const lib_dts = `${resolvedDts}\n\n${lib_logger}`;
+const resolvedEsDts = resolveReferences(lib_es2022_dts);
+const resolvedDomDts = resolveReferences(lib_dom_dts);
+const resolvedDomIterableDts = resolveReferences(lib_dom_iterable_dts);
+export const lib_dts = `${resolvedEsDts}\n\n${resolvedDomDts}\n\n${resolvedDomIterableDts}\n\n${lib_logger}`;