diff --git a/server/api/oauth/token/index.ts b/server/api/oauth/token/index.ts
index d81b2d83..ac7f6e92 100644
--- a/server/api/oauth/token/index.ts
+++ b/server/api/oauth/token/index.ts
@@ -128,14 +128,18 @@ export default (app: Hono) =>
                         access_token: token.accessToken,
                         token_type: "Bearer",
                         expires_in: token.expiresAt
-                            ? (new Date(token.expiresAt).getTime() -
-                                  Date.now()) /
-                              1000
+                            ? Math.floor(
+                                  (new Date(token.expiresAt).getTime() -
+                                      Date.now()) /
+                                      1000,
+                              )
                             : null,
                         id_token: token.idToken,
                         refresh_token: null,
                         scope: token.scope,
-                        created_at: new Date(token.createdAt).toISOString(),
+                        created_at: Math.floor(
+                            new Date(token.createdAt).getTime() / 1000,
+                        ),
                     });
                 }
             }
diff --git a/tests/oauth.test.ts b/tests/oauth.test.ts
index 670db5a2..de5fc402 100644
--- a/tests/oauth.test.ts
+++ b/tests/oauth.test.ts
@@ -152,7 +152,7 @@ describe("POST /oauth/token/", () => {
             access_token: expect.any(String),
             token_type: "Bearer",
             scope: "read write",
-            created_at: expect.any(String),
+            created_at: expect.any(Number),
             expires_in: expect.any(Number),
             id_token: null,
             refresh_token: null,