diff --git a/extensions/RockytheProtogen/FileSystemAccessAPI/fsa-api.js b/extensions/RockytheProtogen/FileSystemAccessAPI/fsa-api.js
new file mode 100644
index 0000000000..52aeab45a0
--- /dev/null
+++ b/extensions/RockytheProtogen/FileSystemAccessAPI/fsa-api.js
@@ -0,0 +1,154 @@
+(function (Scratch) {
+  "use strict";
+
+  if (!Scratch.extensions.unsandboxed) {
+    throw new Error("File System Access API must run unsandboxed");
+  }
+
+  class rtpfsaapi {
+    getInfo() {
+      return {
+        id: "rtpfsaapi",
+        name: "File System Access API",
+        blocks: [
+          {
+            opcode: "filepicker",
+            blockType: "reporter",
+            text: "window.showOpenFilePicker([json])",
+            arguments: {
+              json: {
+                type: "string",
+              },
+            },
+          },
+          {
+            opcode: "filesavepicker",
+            blockType: "reporter",
+            text: "window.showSaveFilePicker([json])",
+            arguments: {
+              json: {
+                type: "string",
+              },
+            },
+          },
+          {
+            opcode: "folderpicker",
+            blockType: "reporter",
+            text: "window.showDirectoryPicker([json])",
+            arguments: {
+              json: {
+                type: "string",
+              },
+            },
+          },
+          {
+            opcode: "getFile",
+            blockType: "reporter",
+            text: "[handle].getFile()",
+            arguments: {
+              handle: {
+                acceptReporters: true,
+              },
+            },
+          },
+          {
+            opcode: "text",
+            blockType: "reporter",
+            text: "[handle].text()",
+            arguments: {
+              handle: {
+                acceptReporters: true,
+              },
+            },
+          },
+          {
+            opcode: "arrayBuffer",
+            blockType: "reporter",
+            text: "[handle].arrayBuffer()",
+            arguments: {
+              handle: {
+                acceptReporters: true,
+              },
+            },
+          },
+          {
+            opcode: "arrayFromArrayBuffer",
+            blockType: "reporter",
+            text: "new Uint8Array([arrayBuffer])",
+            arguments: {
+              handle: {
+                acceptReporters: true,
+              },
+            },
+          },
+        ],
+      };
+    }
+    filepicker(args) {
+      try {
+        return window.showOpenFilePicker(JSON.parse(args.json));
+      } catch (err) {
+        return err;
+      }
+    }
+    filesavepicker(args) {
+      try {
+        return window.showSaveFilePicker(JSON.parse(args.json));
+      } catch (err) {
+        return err;
+      }
+    }
+    folderpicker(args) {
+      try {
+        return window.showDirectoryPicker(JSON.parse(args.json));
+      } catch (err) {
+        return err;
+      }
+    }
+    getFile(args) {
+      try {
+        let handle;
+        [handle] = args.handle;
+        return handle.getFile();
+      } catch (err) {
+        return err;
+      }
+    }
+    slice(args) {
+      try {
+        let handle;
+        const parameters = args.start.split(",");
+        console.log(parameters);
+        handle = args.handle;
+        return handle.slice(parameters[0], parameters[1]);
+      } catch (err) {
+        return err;
+      }
+    }
+    text(args) {
+      try {
+        let handle;
+        handle = args.handle;
+        return handle.text();
+      } catch (err) {
+        return err;
+      }
+    }
+    arrayBuffer(args) {
+      try {
+        let handle;
+        handle = args.handle;
+        return handle.arrayBuffer();
+      } catch (err) {
+        return err;
+      }
+    }
+    arrayFromArrayBuffer(args) {
+      return new Uint8Array(args.arrayBuffer);
+    }
+    async arrayFromBlob(args) {
+      return await new Response(args.blob).arrayBuffer();
+    }
+  }
+  Scratch.extensions.register(new rtpfsaapi());
+})(Scratch);
diff --git a/images/RockytheProtogen/FSA-API-TW-V2B.png b/images/RockytheProtogen/FSA-API-TW-V2B.png
new file mode 100644
index 0000000000..54156be1c1
Binary files /dev/null and b/images/RockytheProtogen/FSA-API-TW-V2B.png differ