diff --git a/lib/micropub/github.rb b/lib/micropub/github.rb
index 664a1bb..b490155 100644
--- a/lib/micropub/github.rb
+++ b/lib/micropub/github.rb
@@ -24,7 +24,7 @@ module Micropub
         path: path,
         message: "Posting: #{post.truncated_content}",
         content: post.post_content,
-        branch: ENV.fetch("GITHUB_BRANCH", "master"),
+        branch: ENV.fetch("GITHUB_BRANCH", "main"),
       )
     end