diff --git a/replay-ui/src/hooks/useKeyboardNav.ts b/replay-ui/src/hooks/useKeyboardNav.ts
index d7a2017..2db6c0a 100644
--- a/replay-ui/src/hooks/useKeyboardNav.ts
+++ b/replay-ui/src/hooks/useKeyboardNav.ts
@@ -1,73 +1,24 @@
 import { useEffect } from "react";
+import { dispatchKey, type KeyboardNavOptions } from "../lib/keyboard-nav";
 
-export interface UseKeyboardNavOptions {
-  onPrev: () => void;
-  onNext: () => void;
-  onJumpStart: () => void;
-  onJumpEnd: () => void;
-  onJumpPrev10: () => void;
-  onJumpNext10: () => void;
-  onJumpNextViolation: () => void;
-}
-
-const NAVIGATION_TAGS = new Set(["INPUT", "TEXTAREA", "SELECT"]);
-const ARROW_OWNING_ROLES = new Set(["tab", "tablist", "option", "listbox", "menuitem", "menu"]);
-
-function targetOwnsArrowKeys(target: HTMLElement | null): boolean {
-  let node: HTMLElement | null = target;
-  while (node) {
-    const role = node.getAttribute?.("role");
-    if (role && ARROW_OWNING_ROLES.has(role)) return true;
-    node = node.parentElement;
-  }
-  return false;
-}
+export type UseKeyboardNavOptions = KeyboardNavOptions;
 
 export function useKeyboardNav(options: UseKeyboardNavOptions) {
   useEffect(() => {
     const handler = (event: KeyboardEvent) => {
-      const target = event.target as HTMLElement | null;
-      if (target && (NAVIGATION_TAGS.has(target.tagName) || target.isContentEditable)) {
-        return;
-      }
-      const isArrow = event.key.startsWith("Arrow");
-      if (isArrow && targetOwnsArrowKeys(target)) {
-        return;
-      }
-      if (event.metaKey || event.ctrlKey || event.altKey) {
-        return;
-      }
-      switch (event.key) {
-        case "ArrowLeft":
-        case "k":
-          if (event.shiftKey) {
-            options.onJumpPrev10();
-          } else {
-            options.onPrev();
-          }
-          event.preventDefault();
-          return;
-        case "ArrowRight":
-        case "j":
-          if (event.shiftKey) {
-            options.onJumpNext10();
-          } else {
-            options.onNext();
-          }
-          event.preventDefault();
-          return;
-        case "g":
-          options.onJumpStart();
-          event.preventDefault();
-          return;
-        case "G":
-          options.onJumpEnd();
-          event.preventDefault();
-          return;
-        case ".":
-          options.onJumpNextViolation();
-          event.preventDefault();
-          return;
+      const handled = dispatchKey(
+        {
+          key: event.key,
+          shiftKey: event.shiftKey,
+          metaKey: event.metaKey,
+          ctrlKey: event.ctrlKey,
+          altKey: event.altKey,
+          target: event.target as HTMLElement | null,
+        },
+        options,
+      );
+      if (handled) {
+        event.preventDefault();
       }
     };
     window.addEventListener("keydown", handler);
diff --git a/replay-ui/src/lib/keyboard-nav.ts b/replay-ui/src/lib/keyboard-nav.ts
new file mode 100644
index 0000000..bf21bc5
--- /dev/null
+++ b/replay-ui/src/lib/keyboard-nav.ts
@@ -0,0 +1,76 @@
+export interface KeyboardNavOptions {
+  onPrev: () => void;
+  onNext: () => void;
+  onJumpStart: () => void;
+  onJumpEnd: () => void;
+  onJumpPrev10: () => void;
+  onJumpNext10: () => void;
+  onJumpNextViolation: () => void;
+}
+
+export interface KeyEvent {
+  key: string;
+  shiftKey?: boolean;
+  metaKey?: boolean;
+  ctrlKey?: boolean;
+  altKey?: boolean;
+  target?: HTMLElement | null;
+}
+
+const NAVIGATION_TAGS = new Set(["INPUT", "TEXTAREA", "SELECT"]);
+const ARROW_OWNING_ROLES = new Set([
+  "tab",
+  "tablist",
+  "option",
+  "listbox",
+  "menuitem",
+  "menu",
+]);
+
+export function targetOwnsArrowKeys(target: HTMLElement | null): boolean {
+  let node: HTMLElement | null = target;
+  while (node) {
+    const role = node.getAttribute?.("role");
+    if (role && ARROW_OWNING_ROLES.has(role)) return true;
+    node = node.parentElement;
+  }
+  return false;
+}
+
+// Returns true when the key was consumed (caller should preventDefault).
+export function dispatchKey(
+  event: KeyEvent,
+  options: KeyboardNavOptions,
+): boolean {
+  const target = event.target ?? null;
+  if (target && (NAVIGATION_TAGS.has(target.tagName) || target.isContentEditable)) {
+    return false;
+  }
+  if (event.key.startsWith("Arrow") && targetOwnsArrowKeys(target)) {
+    return false;
+  }
+  if (event.metaKey || event.ctrlKey || event.altKey) {
+    return false;
+  }
+  switch (event.key) {
+    case "ArrowLeft":
+    case "k":
+      (event.shiftKey ? options.onJumpPrev10 : options.onPrev)();
+      return true;
+    case "ArrowRight":
+    case "j":
+      (event.shiftKey ? options.onJumpNext10 : options.onNext)();
+      return true;
+    case "g":
+      options.onJumpStart();
+      return true;
+    case "G":
+      options.onJumpEnd();
+      return true;
+    case ".":
+      options.onJumpNextViolation();
+      return true;
+    default:
+      return false;
+  }
+}