diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js
index 49ace0b9..09a3e166 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js
@@ -72,61 +72,73 @@
     }
   }
 
-  // src/app.js
+  // src/core/decoder-registry.ts
+  var bridge = window;
+  var readyCallbacks = [];
   var decoderRegistry = [];
-  window.decoderRegistry = decoderRegistry;
-  var _decoderRegistryReadyCallbacks = [];
-  window.onDecoderRegistryReady = function(fn) {
-    if (decoderRegistry.length > 0) fn();
-    else _decoderRegistryReadyCallbacks.push(fn);
-  };
-  (async function fetchDecoderRegistry() {
-    try {
-      const resp = await fetch("/decoders");
-      if (resp.ok) {
-        decoderRegistry = await resp.json();
-        window.decoderRegistry = decoderRegistry;
-        for (const fn of _decoderRegistryReadyCallbacks) fn();
-        _decoderRegistryReadyCallbacks.length = 0;
-        hideUnsupportedDecoderTabs();
-        refreshOperatorLayoutCapabilities();
-      }
-    } catch (e) {
-      console.error("Failed to fetch decoder registry:", e);
-    }
-  })();
-  function hideUnsupportedDecoderTabs() {
-    const knownIds = new Set(decoderRegistry.map(function(d) {
-      return d.id;
-    }));
+  function onDecoderRegistryReady(callback) {
+    if (decoderRegistry.length > 0) callback();
+    else readyCallbacks.push(callback);
+  }
+  function hideUnsupportedDecoderUi() {
+    const knownIds = new Set(decoderRegistry.map(({ id }) => id));
     const alwaysShow = /* @__PURE__ */ new Set(["overview", "rds", "sat"]);
-    document.querySelectorAll("#tab-digital-modes > .sub-tab-bar > .sub-tab[data-subtab]").forEach(function(btn) {
-      const id = btn.dataset.subtab;
-      if (alwaysShow.has(id) || knownIds.has(id)) return;
-      btn.style.display = "none";
-      var panel = document.getElementById("subtab-" + id);
+    document.querySelectorAll(
+      "#tab-digital-modes > .sub-tab-bar > .sub-tab[data-subtab]"
+    ).forEach((button) => {
+      const id = button.dataset.subtab;
+      if (!id || alwaysShow.has(id) || knownIds.has(id)) return;
+      button.style.display = "none";
+      const panel = document.getElementById(`subtab-${id}`);
       if (panel) panel.style.display = "none";
     });
-    document.querySelectorAll('[id^="about-dec-"]').forEach(function(el) {
-      var id = el.id.replace("about-dec-", "");
-      if (!alwaysShow.has(id) && !knownIds.has(id)) {
-        var row = el.closest("tr");
-        if (row) row.style.display = "none";
-      }
+    document.querySelectorAll('[id^="about-dec-"]').forEach((element) => {
+      const id = element.id.replace("about-dec-", "");
+      if (alwaysShow.has(id) || knownIds.has(id)) return;
+      const row = element.closest("tr");
+      if (row) row.style.display = "none";
     });
-    document.querySelectorAll('[id^="settings-clear-"][id$="-history"]').forEach(function(el) {
-      var m = el.id.match(/^settings-clear-(.+)-history$/);
-      if (m && !alwaysShow.has(m[1]) && !knownIds.has(m[1])) {
-        el.style.display = "none";
-      }
+    document.querySelectorAll('[id^="settings-clear-"][id$="-history"]').forEach((element) => {
+      const match = /^settings-clear-(.+)-history$/.exec(element.id);
+      const id = match?.[1];
+      if (id && !alwaysShow.has(id) && !knownIds.has(id)) element.style.display = "none";
     });
-    document.querySelectorAll("#subtab-overview .plugin-item[data-decoder]").forEach(function(el) {
-      var id = el.dataset.decoder;
-      if (!alwaysShow.has(id) && !knownIds.has(id)) {
-        el.style.display = "none";
-      }
+    document.querySelectorAll("#subtab-overview .plugin-item[data-decoder]").forEach((element) => {
+      const id = element.dataset.decoder;
+      if (id && !alwaysShow.has(id) && !knownIds.has(id)) element.style.display = "none";
     });
   }
+  function isDecoderDescriptor(value) {
+    if (typeof value !== "object" || value === null) return false;
+    const item = value;
+    return typeof item.id === "string" && typeof item.label === "string" && typeof item.activation === "string" && Array.isArray(item.active_modes) && item.active_modes.every((mode) => typeof mode === "string") && typeof item.background_decode === "boolean" && typeof item.bookmark_selectable === "boolean";
+  }
+  function decodeRegistry(value) {
+    if (!Array.isArray(value) || !value.every(isDecoderDescriptor)) {
+      throw new TypeError("The decoder registry response is malformed");
+    }
+    return value;
+  }
+  async function loadDecoderRegistry(onLoaded) {
+    try {
+      const response = await fetch("/decoders");
+      if (!response.ok) return;
+      decoderRegistry = decodeRegistry(await response.json());
+      bridge.decoderRegistry = decoderRegistry;
+      readyCallbacks.splice(0).forEach((callback) => {
+        callback();
+      });
+      hideUnsupportedDecoderUi();
+      onLoaded();
+    } catch (error) {
+      console.error("Failed to fetch decoder registry:", error);
+    }
+  }
+  bridge.decoderRegistry = decoderRegistry;
+  bridge.onDecoderRegistryReady = onDecoderRegistryReady;
+
+  // src/app.js
+  void loadDecoderRegistry(refreshOperatorLayoutCapabilities);
   var authRole = null;
   var authEnabled = true;
   async function checkAuthStatus() {
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js
index 7387afcc..7e11ca16 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js
+++ b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js
@@ -11,71 +11,13 @@ import {
 } from "./core/geo.js";
 import { escapeHtml as escapeMapHtml } from "./core/dom.js";
 import { loadSetting, saveSetting } from "./core/settings.js";
+import {
+  decoderRegistry,
+  loadDecoderRegistry,
+} from "./core/decoder-registry.js";
 
 // --- Decoder registry (fetched from /decoders on load) ---
-/** @type {Array<{id:string,label:string,activation:string,active_modes:string[],background_decode:boolean,bookmark_selectable:boolean}>} */
-let decoderRegistry = [];
-window.decoderRegistry = decoderRegistry;
-
-/** Callbacks invoked once the decoder registry is fetched. */
-const _decoderRegistryReadyCallbacks = [];
-window.onDecoderRegistryReady = function (fn) {
-  if (decoderRegistry.length > 0) fn();
-  else _decoderRegistryReadyCallbacks.push(fn);
-};
-
-(async function fetchDecoderRegistry() {
-  try {
-    const resp = await fetch("/decoders");
-    if (resp.ok) {
-      decoderRegistry = await resp.json();
-      window.decoderRegistry = decoderRegistry;
-      for (const fn of _decoderRegistryReadyCallbacks) fn();
-      _decoderRegistryReadyCallbacks.length = 0;
-      hideUnsupportedDecoderTabs();
-      refreshOperatorLayoutCapabilities();
-    }
-  } catch (e) {
-    console.error("Failed to fetch decoder registry:", e);
-  }
-})();
-
-/** Hide decoder sub-tabs, panels, about rows, and settings buttons
- *  for decoders not present in the server's registry. */
-function hideUnsupportedDecoderTabs() {
-  const knownIds = new Set(decoderRegistry.map(function (d) { return d.id; }));
-  // Sub-tabs that are not decoders and should always be visible.
-  const alwaysShow = new Set(["overview", "rds", "sat"]);
-  document.querySelectorAll("#tab-digital-modes > .sub-tab-bar > .sub-tab[data-subtab]").forEach(function (btn) {
-    const id = btn.dataset.subtab;
-    if (alwaysShow.has(id) || knownIds.has(id)) return;
-    btn.style.display = "none";
-    var panel = document.getElementById("subtab-" + id);
-    if (panel) panel.style.display = "none";
-  });
-  // About-tab decoder status rows: <td>LABEL</td><td id="about-dec-ID">
-  document.querySelectorAll('[id^="about-dec-"]').forEach(function (el) {
-    var id = el.id.replace("about-dec-", "");
-    if (!alwaysShow.has(id) && !knownIds.has(id)) {
-      var row = el.closest("tr");
-      if (row) row.style.display = "none";
-    }
-  });
-  // Settings clear-history buttons
-  document.querySelectorAll('[id^="settings-clear-"][id$="-history"]').forEach(function (el) {
-    var m = el.id.match(/^settings-clear-(.+)-history$/);
-    if (m && !alwaysShow.has(m[1]) && !knownIds.has(m[1])) {
-      el.style.display = "none";
-    }
-  });
-  // Overview decoder descriptions
-  document.querySelectorAll("#subtab-overview .plugin-item[data-decoder]").forEach(function (el) {
-    var id = el.dataset.decoder;
-    if (!alwaysShow.has(id) && !knownIds.has(id)) {
-      el.style.display = "none";
-    }
-  });
-}
+void loadDecoderRegistry(refreshOperatorLayoutCapabilities);
 
 // --- Authentication ---
 let authRole = null;  // null (not authenticated), "rx" (read-only), or "control" (full access)
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/core/decoder-registry.ts b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/core/decoder-registry.ts
new file mode 100644
index 00000000..763c1c65
--- /dev/null
+++ b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/core/decoder-registry.ts
@@ -0,0 +1,100 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+export interface DecoderDescriptor {
+  id: string;
+  label: string;
+  activation: string;
+  active_modes: string[];
+  background_decode: boolean;
+  bookmark_selectable: boolean;
+}
+
+interface DecoderRegistryBridge extends Window {
+  decoderRegistry?: DecoderDescriptor[];
+  onDecoderRegistryReady?: (callback: () => void) => void;
+}
+
+const bridge = window as DecoderRegistryBridge;
+const readyCallbacks: Array<() => void> = [];
+
+export let decoderRegistry: DecoderDescriptor[] = [];
+
+export function onDecoderRegistryReady(callback: () => void): void {
+  if (decoderRegistry.length > 0) callback();
+  else readyCallbacks.push(callback);
+}
+
+function hideUnsupportedDecoderUi(): void {
+  const knownIds = new Set(decoderRegistry.map(({ id }) => id));
+  const alwaysShow = new Set(["overview", "rds", "sat"]);
+
+  document.querySelectorAll<HTMLElement>(
+    "#tab-digital-modes > .sub-tab-bar > .sub-tab[data-subtab]",
+  ).forEach((button) => {
+    const id = button.dataset.subtab;
+    if (!id || alwaysShow.has(id) || knownIds.has(id)) return;
+    button.style.display = "none";
+    const panel = document.getElementById(`subtab-${id}`);
+    if (panel) panel.style.display = "none";
+  });
+
+  document.querySelectorAll<HTMLElement>('[id^="about-dec-"]').forEach((element) => {
+    const id = element.id.replace("about-dec-", "");
+    if (alwaysShow.has(id) || knownIds.has(id)) return;
+    const row = element.closest<HTMLElement>("tr");
+    if (row) row.style.display = "none";
+  });
+
+  document.querySelectorAll<HTMLElement>('[id^="settings-clear-"][id$="-history"]')
+    .forEach((element) => {
+      const match = /^settings-clear-(.+)-history$/.exec(element.id);
+      const id = match?.[1];
+      if (id && !alwaysShow.has(id) && !knownIds.has(id)) element.style.display = "none";
+    });
+
+  document.querySelectorAll<HTMLElement>("#subtab-overview .plugin-item[data-decoder]")
+    .forEach((element) => {
+      const id = element.dataset.decoder;
+      if (id && !alwaysShow.has(id) && !knownIds.has(id)) element.style.display = "none";
+    });
+}
+
+function isDecoderDescriptor(value: unknown): value is DecoderDescriptor {
+  if (typeof value !== "object" || value === null) return false;
+  const item = value as Partial<DecoderDescriptor>;
+  return typeof item.id === "string"
+    && typeof item.label === "string"
+    && typeof item.activation === "string"
+    && Array.isArray(item.active_modes)
+    && item.active_modes.every((mode) => typeof mode === "string")
+    && typeof item.background_decode === "boolean"
+    && typeof item.bookmark_selectable === "boolean";
+}
+
+function decodeRegistry(value: unknown): DecoderDescriptor[] {
+  if (!Array.isArray(value) || !value.every(isDecoderDescriptor)) {
+    throw new TypeError("The decoder registry response is malformed");
+  }
+  return value;
+}
+
+export async function loadDecoderRegistry(onLoaded: () => void): Promise<void> {
+  try {
+    const response = await fetch("/decoders");
+    if (!response.ok) return;
+    decoderRegistry = decodeRegistry(await response.json());
+    bridge.decoderRegistry = decoderRegistry;
+    readyCallbacks.splice(0).forEach((callback) => { callback(); });
+    hideUnsupportedDecoderUi();
+    onLoaded();
+  } catch (error: unknown) {
+    console.error("Failed to fetch decoder registry:", error);
+  }
+}
+
+// Temporary compatibility boundary for lazy modules that have not yet been
+// changed to receive the registry service through their plugin context.
+bridge.decoderRegistry = decoderRegistry;
+bridge.onDecoderRegistryReady = onDecoderRegistryReady;