diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index bf0d036..3549461 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "3.5.0"
+  ".": "3.5.1"
 }
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index aa63131..c0ee849 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 3.5.1 (2026-02-03)
+
+Full Changelog: [v3.5.0...v3.5.1](https://github.com/browserbase/stagehand-ruby/compare/v3.5.0...v3.5.1)
+
+### Bug Fixes
+
+* **client:** always add content-length to post body, even when empty ([7c7c43e](https://github.com/browserbase/stagehand-ruby/commit/7c7c43e51dd621d74dab8d1fa47de0dcc9bc0a28))
+
 ## 3.5.0 (2026-02-03)
 
 Full Changelog: [v3.4.0...v3.5.0](https://github.com/browserbase/stagehand-ruby/compare/v3.4.0...v3.5.0)
diff --git a/Gemfile.lock b/Gemfile.lock
index c6f46df..c29ea56 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,7 @@ GIT
 PATH
   remote: .
   specs:
-    stagehand (3.5.0)
+    stagehand (3.5.1)
       cgi
       connection_pool
 
diff --git a/lib/stagehand/internal/transport/pooled_net_requester.rb b/lib/stagehand/internal/transport/pooled_net_requester.rb
index 66e8b12..f8655dd 100644
--- a/lib/stagehand/internal/transport/pooled_net_requester.rb
+++ b/lib/stagehand/internal/transport/pooled_net_requester.rb
@@ -75,7 +75,7 @@ def build_request(request, &blk)
 
             case body
             in nil
-              nil
+              req["content-length"] ||= 0 unless req["transfer-encoding"]
             in String
               req["content-length"] ||= body.bytesize.to_s unless req["transfer-encoding"]
               req.body_stream = Stagehand::Internal::Util::ReadIOAdapter.new(body, &blk)
diff --git a/lib/stagehand/version.rb b/lib/stagehand/version.rb
index 2f29a29..23c52d4 100644
--- a/lib/stagehand/version.rb
+++ b/lib/stagehand/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Stagehand
-  VERSION = "3.5.0"
+  VERSION = "3.5.1"
 end