Trigger delete cache of url
Add a cache tag to the response of /api/v1/get-list:

$build = [
  '#cache' =&gt; [
    'contexts' =&gt; ['url','url.query_args'],
    'max-age' =&gt; 3600,
    'tags' =&gt; ['api-v1-list'],
  ],
];


and then invalidate this tag in /api/v1/post-item:

\Drupal\Core\Cache\Cache::invalidateTags(['api-v1-list']);