diff --git a/source/storage/anonymize-usernames.ts b/source/storage/anonymize-usernames.ts
new file mode 100644
index 0000000..7653a78
--- /dev/null
+++ b/source/storage/anonymize-usernames.ts
@@ -0,0 +1,23 @@
+/**
+ * The different types of username replacements for the Anonymize Usernames
+ * feature.
+ */
+export enum ReplacementType {
+  Hashed = "hashed",
+  Numerical = "numerical",
+}
+
+/**
+ * Type guard check to see if a string is a valid {@link ReplacementType}.
+ * @param input The string to check.
+ */
+export function isReplacementType(input: string): input is ReplacementType {
+  return Object.values(ReplacementType).includes(input as ReplacementType);
+}
+
+/**
+ * The data stored for the Anonymize Usernames feature.
+ */
+export type AnonymizeUsernamesData = {
+  replacementType: ReplacementType;
+};
diff --git a/source/storage/exports.ts b/source/storage/exports.ts
index f29625a..131075c 100644
--- a/source/storage/exports.ts
+++ b/source/storage/exports.ts
@@ -1,23 +1,18 @@
 import {createValue, type Value} from "@holllo/webextension-storage";
 import browser from "webextension-polyfill";
+import {type AnonymizeUsernamesData} from "./anonymize-usernames.js";
 import {Data, Feature, MiscellaneousFeature} from "./enums.js";
 import {collectHideTopicsData} from "./hide-topics.js";
 import {defaultKnownGroups} from "./known-groups.js";
 import {collectUsernameColors} from "./username-color.js";
 import {collectUserLabels} from "./user-label.js";
 
+export * from "./anonymize-usernames.js";
 export * from "./enums.js";
 export * from "./hide-topics.js";
 export * from "./username-color.js";
 export * from "./user-label.js";
 
-/**
- * The data stored for the Anonymize Usernames feature.
- */
-export type AnonymizeUsernamesData = {
-  replacementType: "numerical" | "hashed";
-};
-
 /**
  * The data stored for the Hide Votes feature.
  */