diff --git a/lib/routes/bins/create.js b/lib/routes/bins/create.js
index 842af802..44492aa2 100644
--- a/lib/routes/bins/create.js
+++ b/lib/routes/bins/create.js
@@ -40,6 +40,8 @@ module.exports = (client) => (req, res, next) => {
 	}
 
 	mock.content.size = 0;
+	// express is sensitive to mismatched content-length header
+	mock.headers = mock.headers.filter((header) => header.name.toLowerCase() !== "content-length");
 
 	validate
 		.response(mock)
diff --git a/lib/routes/bins/update.js b/lib/routes/bins/update.js
index 6aea1f59..43cf198f 100644
--- a/lib/routes/bins/update.js
+++ b/lib/routes/bins/update.js
@@ -37,6 +37,8 @@ module.exports = (client) => (req, res, next) => {
 	}
 
 	mock.content.size = 0;
+	// express is sensitive to mismatched content-length header
+	mock.headers = mock.headers.filter((header) => header.name.toLowerCase() !== "content-length");
 
 	validate
 		.response(mock)