diff --git a/packages/backend/src/server/api/mastodon/endpoints/auth.ts b/packages/backend/src/server/api/mastodon/endpoints/auth.ts
new file mode 100644
index 000000000..48b5ec55c
--- /dev/null
+++ b/packages/backend/src/server/api/mastodon/endpoints/auth.ts
@@ -0,0 +1,74 @@
+import type { MegalodonInterface } from "megalodon";
+import type { FastifyRequest } from 'fastify';
+
+const readScope = [
+	"read:account",
+	"read:drive",
+	"read:blocks",
+	"read:favorites",
+	"read:following",
+	"read:messaging",
+	"read:mutes",
+	"read:notifications",
+	"read:reactions",
+	"read:pages",
+	"read:page-likes",
+	"read:user-groups",
+	"read:channels",
+	"read:gallery",
+	"read:gallery-likes",
+];
+
+const writeScope = [
+	"write:account",
+	"write:drive",
+	"write:blocks",
+	"write:favorites",
+	"write:following",
+	"write:messaging",
+	"write:mutes",
+	"write:notes",
+	"write:notifications",
+	"write:reactions",
+	"write:votes",
+	"write:pages",
+	"write:page-likes",
+	"write:user-groups",
+	"write:channels",
+	"write:gallery",
+	"write:gallery-likes",
+];
+
+export async function apiAuthMastodon(request: FastifyRequest, client: MegalodonInterface) {
+		const body: any = request.body || request.query;
+		try {
+			let scope = body.scopes;
+			if (typeof scope === "string") scope = scope.split(" ");
+			const pushScope = new Set<string>();
+			for (const s of scope) {
+				if (s.match(/^read/)) for (const r of readScope) pushScope.add(r);
+				if (s.match(/^write/)) for (const r of writeScope) pushScope.add(r);
+			}
+			const scopeArr = Array.from(pushScope);
+
+			const red = body.redirect_uris;
+			const appData = await client.registerApp(body.client_name, {
+				scopes: scopeArr,
+				redirect_uris: red,
+				website: body.website,
+			});
+			const returns = {
+				id: Math.floor(Math.random() * 100).toString(),
+				name: appData.name,
+				website: body.website,
+				redirect_uri: red,
+				client_id: Buffer.from(appData.url || "").toString("base64"),
+				client_secret: appData.clientSecret,
+			};
+            
+			return returns;
+		} catch (e: any) {
+			console.error(e);
+			return e.response.data;
+		}
+}