diff --git a/package.json b/package.json
index ffadc2c61..c95c2bb8a 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,7 @@
   "scripts": {
     "dev": "vite",
     "build": "npm run typecheck && vite build",
-    "deploy": "node scripts/deploy.js",
+    "deploy": "npm run build && node scripts/deploy.js",
     "zipdist": "node scripts/zipdist.js",
     "typecheck": "tsc --noEmit",
     "format": "prettier --write 'src/**/*.{js,ts,tsx,vue}'",
diff --git a/src/scripts/api.ts b/src/scripts/api.ts
index 1001c90c6..3f8bc3d14 100644
--- a/src/scripts/api.ts
+++ b/src/scripts/api.ts
@@ -4,6 +4,7 @@ import {
   PendingTaskItem,
   RunningTaskItem,
   ComfyNodeDef,
+  validateComfyNodeDef,
 } from "@/types/apiTypes";
 
 interface QueuePromptRequestBody {
@@ -240,7 +241,17 @@ class ComfyApi extends EventTarget {
    */
   async getNodeDefs(): Promise<Record<string, ComfyNodeDef>> {
     const resp = await this.fetchApi("/object_info", { cache: "no-store" });
-    return await resp.json();
+    const objectInfoUnsafe = await resp.json();
+    const objectInfo: Record<string, ComfyNodeDef> = {};
+    for (const key in objectInfoUnsafe) {
+      try {
+        objectInfo[key] = validateComfyNodeDef(objectInfoUnsafe[key]);
+      } catch (e) {
+        console.warn("Ignore node definition: ", key);
+        console.error(e);
+      }
+    }
+    return objectInfo;
   }
 
   /**
diff --git a/src/types/apiTypes.ts b/src/types/apiTypes.ts
index 4c3b167da..98c3bec37 100644
--- a/src/types/apiTypes.ts
+++ b/src/types/apiTypes.ts
@@ -1,5 +1,6 @@
 import { ZodType, z } from "zod";
 import { zComfyWorkflow } from "./comfyWorkflow";
+import { fromZodError } from "zod-validation-error";
 
 const zNodeId = z.number();
 const zNodeType = z.string();
@@ -124,9 +125,21 @@ export type TaskItem = z.infer<typeof zTaskItem>;
 
 // TODO: validate `/history` `/queue` API endpoint responses.
 
-function inputSpec(spec: [ZodType, ZodType]): ZodType {
+function inputSpec(
+  spec: [ZodType, ZodType],
+  allowUpcast: boolean = true
+): ZodType {
   const [inputType, inputSpec] = spec;
-  return z.union([z.tuple([inputType, inputSpec]), z.tuple([inputType])]);
+  // e.g. "INT" => ["INT", {}]
+  const upcastTypes: ZodType[] = allowUpcast
+    ? [inputType.transform((type) => [type, {}])]
+    : [];
+
+  return z.union([
+    z.tuple([inputType, inputSpec]),
+    z.tuple([inputType]).transform(([type]) => [type, {}]),
+    ...upcastTypes,
+  ]);
 }
 
 const zIntInputSpec = inputSpec([
@@ -173,15 +186,18 @@ const zStringInputSpec = inputSpec([
 ]);
 
 // Dropdown Selection.
-const zComboInputSpec = inputSpec([
-  z.array(z.any()),
-  z.object({
-    default: z.any().optional(),
-    control_after_generate: z.boolean().optional(),
-    image_upload: z.boolean().optional(),
-    forceInput: z.boolean().optional(),
-  }),
-]);
+const zComboInputSpec = inputSpec(
+  [
+    z.array(z.any()),
+    z.object({
+      default: z.any().optional(),
+      control_after_generate: z.boolean().optional(),
+      image_upload: z.boolean().optional(),
+      forceInput: z.boolean().optional(),
+    }),
+  ],
+  /* allowUpcast=*/ false
+);
 
 const zCustomInputSpec = inputSpec([
   z.string(),
@@ -210,6 +226,9 @@ const zComfyNodeDef = z.object({
   input: z.object({
     required: z.record(zInputSpec).optional(),
     optional: z.record(zInputSpec).optional(),
+    // Frontend repo is not using it, but some custom nodes are using the
+    // hidden field to pass various values.
+    hidden: z.record(z.any()).optional(),
   }),
   output: zComfyOutputSpec,
   output_is_list: z.array(z.boolean()),
@@ -227,4 +246,15 @@ export type ComfyInputSpec = z.infer<typeof zInputSpec>;
 export type ComfyOutputSpec = z.infer<typeof zComfyOutputSpec>;
 export type ComfyNodeDef = z.infer<typeof zComfyNodeDef>;
 
-// TODO: validate `/object_info` API endpoint responses.
+export function validateComfyNodeDef(data: any): ComfyNodeDef {
+  const result = zComfyNodeDef.safeParse(data);
+  if (!result.success) {
+    const zodError = fromZodError(result.error);
+    const error = new Error(
+      `Invalid ComfyNodeDef: ${JSON.stringify(data)}\n${zodError.message}`
+    );
+    error.cause = zodError;
+    throw error;
+  }
+  return result.data;
+}
diff --git a/tests-ui/tests/apiTypes.test.ts b/tests-ui/tests/apiTypes.test.ts
new file mode 100644
index 000000000..335793713
--- /dev/null
+++ b/tests-ui/tests/apiTypes.test.ts
@@ -0,0 +1,77 @@
+import { ComfyNodeDef, validateComfyNodeDef } from "@/types/apiTypes";
+const fs = require("fs");
+const path = require("path");
+
+const EXAMPLE_NODE_DEF: ComfyNodeDef = {
+  input: {
+    required: {
+      ckpt_name: [["model1.safetensors", "model2.ckpt"]],
+    },
+  },
+  output: ["MODEL", "CLIP", "VAE"],
+  output_is_list: [false, false, false],
+  output_name: ["MODEL", "CLIP", "VAE"],
+  name: "CheckpointLoaderSimple",
+  display_name: "Load Checkpoint",
+  description: "",
+  python_module: "nodes",
+  category: "loaders",
+  output_node: false,
+};
+
+describe("validateNodeDef", () => {
+  it("Should accept a valid node definition", () => {
+    expect(() => validateComfyNodeDef(EXAMPLE_NODE_DEF)).not.toThrow();
+  });
+
+  describe.each([
+    [{ ckpt_name: "foo" }, ["foo", {}]],
+    [{ ckpt_name: ["foo"] }, ["foo", {}]],
+    [{ ckpt_name: ["foo", { default: 1 }] }, ["foo", { default: 1 }]],
+  ])(
+    "validateComfyNodeDef with various input spec formats",
+    (inputSpec, expected) => {
+      it(`should accept input spec format: ${JSON.stringify(inputSpec)}`, () => {
+        expect(
+          validateComfyNodeDef({
+            ...EXAMPLE_NODE_DEF,
+            input: {
+              required: inputSpec,
+            },
+          }).input.required.ckpt_name
+        ).toEqual(expected);
+      });
+    }
+  );
+
+  describe.each([
+    [{ ckpt_name: { "model1.safetensors": "foo" } }],
+    [{ ckpt_name: ["*", ""] }],
+    [{ ckpt_name: ["foo", { default: 1 }, { default: 2 }] }],
+  ])(
+    "validateComfyNodeDef rejects with various input spec formats",
+    (inputSpec) => {
+      it(`should accept input spec format: ${JSON.stringify(inputSpec)}`, () => {
+        expect(() =>
+          validateComfyNodeDef({
+            ...EXAMPLE_NODE_DEF,
+            input: {
+              required: inputSpec,
+            },
+          })
+        ).toThrow();
+      });
+    }
+  );
+
+  it("Should accept all built-in node definitions", async () => {
+    const nodeDefs = Object.values(
+      JSON.parse(
+        fs.readFileSync(path.resolve("./tests-ui/data/object_info.json"))
+      )
+    );
+    nodeDefs.forEach((nodeDef) => {
+      expect(() => validateComfyNodeDef(nodeDef)).not.toThrow();
+    });
+  });
+});