diff --git a/tools/upend_js/api.ts b/tools/upend_js/api.ts
index 35ce220..54e3335 100644
--- a/tools/upend_js/api.ts
+++ b/tools/upend_js/api.ts
@@ -15,6 +15,7 @@ import type {
 import init_wasm from "upend_wasm";
 import {
   AddressComponents,
+  AddressTypeConstants,
   addr_to_components,
   components_to_addr,
 } from "upend_wasm";
@@ -209,6 +210,15 @@ export class UpEndApi {
   ): Promise<string> {
     let response;
     if (typeof input === "string") {
+      try {
+        await this.initWasm();
+        const addressConstants = new AddressTypeConstants();
+        return addressConstants[
+          input.toLowerCase() as "hash" | "uuid" | "attribute" | "url"
+        ];
+      } catch (err) {
+        console.warn(err);
+      }
       response = await fetch(`${this.apiUrl}/address?type=${input}`);
     } else {
       if ("attribute" in input) {
diff --git a/tools/upend_js/package.json b/tools/upend_js/package.json
index 55ba96d..7fefb12 100644
--- a/tools/upend_js/package.json
+++ b/tools/upend_js/package.json
@@ -21,6 +21,6 @@
   "dependencies": {
     "debug": "^4.3.4",
     "lru-cache": "^7.0.0",
-    "upend_wasm": "file:../upend_wasm/pkg"
+    "upend_wasm": "../upend_wasm/pkg"
   }
 }
diff --git a/tools/upend_js/yarn.lock b/tools/upend_js/yarn.lock
index 263fb68..e41404c 100644
--- a/tools/upend_js/yarn.lock
+++ b/tools/upend_js/yarn.lock
@@ -3632,14 +3632,14 @@ __metadata:
     eslint: ^8.7.0
     lru-cache: ^7.0.0
     typescript: ^4.4.4
-    upend_wasm: "file:../upend_wasm/pkg"
+    upend_wasm: ../upend_wasm/pkg
   languageName: unknown
   linkType: soft
 
 "upend_wasm@file:../upend_wasm/pkg::locator=upend%40workspace%3A.":
   version: 0.1.0
-  resolution: "upend_wasm@file:../upend_wasm/pkg#../upend_wasm/pkg::hash=10772a&locator=upend%40workspace%3A."
-  checksum: 26c11aa145ba9a5209dac83cbf6c4bc6236d88364a9797030afe9cc3452f1f5daf23014926dfe2f1aea5289494ff166f8c897e766c808af939f1d953ddc0d483
+  resolution: "upend_wasm@file:../upend_wasm/pkg#../upend_wasm/pkg::hash=aca1db&locator=upend%40workspace%3A."
+  checksum: 16eccf41a8d884154d2170602da4ffa44cf3f601c8f6a9cd26637864183bba003f9bb38ecdab93306dd6f6d22a3893946676f211a3e14581bc249f0ce1dd0b1c
   languageName: node
   linkType: hard
 
diff --git a/tools/upend_wasm/src/lib.rs b/tools/upend_wasm/src/lib.rs
index d44ff47..22a5554 100644
--- a/tools/upend_wasm/src/lib.rs
+++ b/tools/upend_wasm/src/lib.rs
@@ -1,5 +1,6 @@
 use upend_base::{
     addressing::{Address, AddressComponents},
+    constants,
     error::UpEndError,
 };
 use wasm_bindgen::prelude::*;
@@ -40,3 +41,34 @@ pub fn components_to_addr(components: AddressComponents) -> Result<String, WasmE
 
     Ok(address.to_string())
 }
+
+#[wasm_bindgen]
+pub struct AddressTypeConstants {}
+
+#[wasm_bindgen]
+impl AddressTypeConstants {
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> Self {
+        AddressTypeConstants {}
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn hash(&self) -> String {
+        constants::TYPE_HASH_ADDRESS.to_string()
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn uuid(&self) -> String {
+        constants::TYPE_UUID_ADDRESS.to_string()
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn attribute(&self) -> String {
+        constants::TYPE_ATTRIBUTE_ADDRESS.to_string()
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn url(&self) -> String {
+        constants::TYPE_URL_ADDRESS.to_string()
+    }
+}
diff --git a/webui/yarn.lock b/webui/yarn.lock
index 8ee0717..48600f8 100644
--- a/webui/yarn.lock
+++ b/webui/yarn.lock
@@ -12585,19 +12585,19 @@ __metadata:
 
 "upend@file:../tools/upend_js::locator=upend-kestrel%40workspace%3A.":
   version: 0.0.1
-  resolution: "upend@file:../tools/upend_js#../tools/upend_js::hash=2d3140&locator=upend-kestrel%40workspace%3A."
+  resolution: "upend@file:../tools/upend_js#../tools/upend_js::hash=6d7a60&locator=upend-kestrel%40workspace%3A."
   dependencies:
     debug: ^4.3.4
     lru-cache: ^7.0.0
-    upend_wasm: "file:../upend_wasm/pkg"
-  checksum: 3ac07a91311fe2fbf25d1e95dd8231b87d82457457c242c6095ee6419f3f5997a037a6f0eaa826e90ba16f70985750da2f7af2a8f4da25f421370e42fbb2def1
+    upend_wasm: ../upend_wasm/pkg
+  checksum: 4b4d166c0e048ae2c3d3dc72519a64e7b3b30e3c357c5333bc2361d28a218bc9e28e333f9a3fa02896143065a3b9efc337a860bb550eb78635a5607d2afcfe50
   languageName: node
   linkType: hard
 
-"upend_wasm@file:../upend_wasm/pkg::locator=upend%40file%3A..%2Ftools%2Fupend_js%23..%2Ftools%2Fupend_js%3A%3Ahash%3D2d3140%26locator%3Dupend-kestrel%2540workspace%253A.":
+"upend_wasm@file:../upend_wasm/pkg::locator=upend%40file%3A..%2Ftools%2Fupend_js%23..%2Ftools%2Fupend_js%3A%3Ahash%3D6d7a60%26locator%3Dupend-kestrel%2540workspace%253A.":
   version: 0.1.0
-  resolution: "upend_wasm@file:../upend_wasm/pkg#../upend_wasm/pkg::hash=10772a&locator=upend%40file%3A..%2Ftools%2Fupend_js%23..%2Ftools%2Fupend_js%3A%3Ahash%3D2d3140%26locator%3Dupend-kestrel%2540workspace%253A."
-  checksum: 26c11aa145ba9a5209dac83cbf6c4bc6236d88364a9797030afe9cc3452f1f5daf23014926dfe2f1aea5289494ff166f8c897e766c808af939f1d953ddc0d483
+  resolution: "upend_wasm@file:../upend_wasm/pkg#../upend_wasm/pkg::hash=cb9d21&locator=upend%40file%3A..%2Ftools%2Fupend_js%23..%2Ftools%2Fupend_js%3A%3Ahash%3D6d7a60%26locator%3Dupend-kestrel%2540workspace%253A."
+  checksum: 51385c3bfda2d3fff7e579e9b350866ef5f8f3f5cac30d5ae1a0a6785c0ff49b2018b68b3492f1be8e983395c5685b09d799d368a5b2d9d6e8a4ec0f38bd0d21
   languageName: node
   linkType: hard