diff --git a/config/config.exs b/config/config.exs
index 33ad87d..d13479a 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -12,7 +12,8 @@ config :decentralised_book_index, Oban,
   repo: DecentralisedBookIndex.Repo,
   queues: [default: 14],
   plugins: [
-    Oban.Plugins.Pruner,
+    # A job will be pruned after 7 days.
+    {Oban.Plugins.Pruner, max_age: 7*24*60*60},
     {Oban.Plugins.Cron,
      crontab: [
       {"@daily", DecentralisedBookIndex.SyncWorker},