diff --git a/packages/backend/test/mfm.ts b/packages/backend/test/mfm.ts
index 605daa7107..ef02e64b91 100644
--- a/packages/backend/test/mfm.ts
+++ b/packages/backend/test/mfm.ts
@@ -55,33 +55,33 @@ describe("fromHtml", () => {
 
 	it("link with different text", () => {
 		assert.deepStrictEqual(
-			fromHtml('<p>a <a href="https://example.com/b">c</a> d</p>'),
-			"a [c](https://example.com/b) d",
+			fromHtml('<p>a <a href="https://calckey.org/b">c</a> d</p>'),
+			"a [c](https://calckey.org/b) d",
 		);
 	});
 
 	it("link with different text, but not encoded", () => {
 		assert.deepStrictEqual(
-			fromHtml('<p>a <a href="https://example.com/ä">c</a> d</p>'),
-			"a [c](<https://example.com/ä>) d",
+			fromHtml('<p>a <a href="https://calckey.org/ä">c</a> d</p>'),
+			"a [c](<https://calckey.org/ä>) d",
 		);
 	});
 
 	it("link with same text", () => {
 		assert.deepStrictEqual(
 			fromHtml(
-				'<p>a <a href="https://example.com/b">https://example.com/b</a> d</p>',
+				'<p>a <a href="https://calckey.org/b">https://calckey.org/b</a> d</p>',
 			),
-			"a https://example.com/b d",
+			"a https://calckey.org/b d",
 		);
 	});
 
 	it("link with same text, but not encoded", () => {
 		assert.deepStrictEqual(
 			fromHtml(
-				'<p>a <a href="https://example.com/ä">https://example.com/ä</a> d</p>',
+				'<p>a <a href="https://calckey.org/ä">https://calckey.org/ä</a> d</p>',
 			),
-			"a <https://example.com/ä> d",
+			"a <https://calckey.org/ä> d",
 		);
 	});
 
@@ -98,8 +98,8 @@ describe("fromHtml", () => {
 
 	it("link without text", () => {
 		assert.deepStrictEqual(
-			fromHtml('<p>a <a href="https://example.com/b"></a> d</p>'),
-			"a https://example.com/b d",
+			fromHtml('<p>a <a href="https://calckey.org/b"></a> d</p>'),
+			"a https://calckey.org/b d",
 		);
 	});
 
@@ -110,15 +110,15 @@ describe("fromHtml", () => {
 	it("mention", () => {
 		assert.deepStrictEqual(
 			fromHtml(
-				'<p>a <a href="https://example.com/@user" class="u-url mention">@user</a> d</p>',
+				'<p>a <a href="https://calckey.org/@user" class="u-url mention">@user</a> d</p>',
 			),
-			"a @user@example.com d",
+			"a @user@calckey.org d",
 		);
 	});
 
 	it("hashtag", () => {
 		assert.deepStrictEqual(
-			fromHtml('<p>a <a href="https://example.com/tags/a">#a</a> d</p>', [
+			fromHtml('<p>a <a href="https://calckey.org/tags/a">#a</a> d</p>', [
 				"#a",
 			]),
 			"a #a d",
diff --git a/packages/client/src/components/MkSample.vue b/packages/client/src/components/MkSample.vue
index fcd064fdc1..cf0c32130c 100644
--- a/packages/client/src/components/MkSample.vue
+++ b/packages/client/src/components/MkSample.vue
@@ -55,7 +55,7 @@ export default defineComponent({
 				this.$i ? this.$i.username : "guest"
 			}.\nAlso, here is ${config.url} and [example link](${
 				config.url
-			}). for more details, see https://example.com.\nAs you know #misskey is open-source software.`,
+			}). for more details, see https://calckey.org.\nAs you know #misskey is open-source software.`,
 		};
 	},
 
diff --git a/packages/client/src/pages/mfm-cheat-sheet.vue b/packages/client/src/pages/mfm-cheat-sheet.vue
index 754f19e936..20f69a6cef 100644
--- a/packages/client/src/pages/mfm-cheat-sheet.vue
+++ b/packages/client/src/pages/mfm-cheat-sheet.vue
@@ -427,7 +427,7 @@ import { instance } from "@/instance";
 
 let preview_mention = $ref("@example");
 let preview_hashtag = $ref("#test");
-let preview_link = $ref(`[${i18n.ts._mfm.dummy}](https://example.com)`);
+let preview_link = $ref(`[${i18n.ts._mfm.dummy}](https://calckey.org)`);
 let preview_emoji = $ref(
 	instance.emojis.length ? `:${instance.emojis[0].name}:` : ":emojiname:"
 );