diff --git a/scarf-gateway.cabal b/scarf-gateway.cabal
index 2e27ef7..71ce31d 100644
--- a/scarf-gateway.cabal
+++ b/scarf-gateway.cabal
@@ -106,6 +106,7 @@ library
     , bytestring
     , case-insensitive
     , conduit
+    , containers
     , cryptohash-sha256
     , exceptions
     , hashable
diff --git a/src/Scarf/Gateway/Rule.hs b/src/Scarf/Gateway/Rule.hs
index 3d51ef8..407e53b 100644
--- a/src/Scarf/Gateway/Rule.hs
+++ b/src/Scarf/Gateway/Rule.hs
@@ -36,6 +36,7 @@ import Data.ByteString.Base64.URL (encode)
 import Data.ByteString.Builder (Builder, char7, string7, toLazyByteString)
 import Data.ByteString.Char8 qualified as BS
 import Data.ByteString.Lazy qualified as LBS
+import Data.Containers.ListUtils (nubOrdOn)
 import Data.HashMap.Strict (HashMap)
 import Data.HashMap.Strict qualified as HashMap
 import Data.HashSet (HashSet)
@@ -665,7 +666,7 @@ rewriteQueryString redirectTarget request
           -- times -- after all, query strings may contain more than one occurrence of
           -- a variable.
           combinedQuery =
-            redirectTargetQuery <> requestQuery
+            nubOrdOn fst (redirectTargetQuery <> requestQuery)
 
           renderedQuery =
             Text.decodeUtf8
diff --git a/test/golden/file-package-with-variables-1.output.yaml b/test/golden/file-package-with-variables-1.output.yaml
index 61db44e..9a7057b 100644
--- a/test/golden/file-package-with-variables-1.output.yaml
+++ b/test/golden/file-package-with-variables-1.output.yaml
@@ -3,13 +3,13 @@ capture: |-
     FlatfileCapture
       { fileAbsoluteUrl =
           Just
-            "https://datausa.io/api/data?drilldowns=Nation&measures=Population&drilldowns=Nation&measures=Population"
+            "https://datausa.io/api/data?drilldowns=Nation&measures=Population"
       , fileVariables =
           fromList
             [ ( "drilldowns" , "Nation" ) , ( "measures" , "Population" ) ]
       , filePackage = "a1b331fa-1539-49e5-bdc4-dc8a48e586d1"
       }
 headers:
-  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population&drilldowns=Nation&measures=Population
+  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population
 query: ?drilldowns=Nation&measures=Population
 status: 302
diff --git a/test/golden/file-package-with-variables-2.output.yaml b/test/golden/file-package-with-variables-2.output.yaml
index d0dde97..18c77b1 100644
--- a/test/golden/file-package-with-variables-2.output.yaml
+++ b/test/golden/file-package-with-variables-2.output.yaml
@@ -3,13 +3,13 @@ capture: |-
     FlatfileCapture
       { fileAbsoluteUrl =
           Just
-            "https://datausa.io/api/data?drilldowns=Nation&measures=Population&measures=Population"
+            "https://datausa.io/api/data?drilldowns=Nation&measures=Population"
       , fileVariables =
           fromList
             [ ( "drilldowns" , "Nation" ) , ( "measures" , "Population" ) ]
       , filePackage = "a1b331fa-1539-49e5-bdc4-dc8a48e586d1"
       }
 headers:
-  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population&measures=Population
+  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population
 query: ?measures=Population
 status: 302
diff --git a/test/golden/file-package-without-varible-1.output.yaml b/test/golden/file-package-without-varible-1.output.yaml
index 5b09cd2..4c4ffcf 100644
--- a/test/golden/file-package-without-varible-1.output.yaml
+++ b/test/golden/file-package-without-varible-1.output.yaml
@@ -3,11 +3,11 @@ capture: |-
     FlatfileCapture
       { fileAbsoluteUrl =
           Just
-            "https://datausa.io/api/data?drilldowns=Nation&measures=Population&drilldowns=Nation&measures=Population"
+            "https://datausa.io/api/data?drilldowns=Nation&measures=Population"
       , fileVariables = fromList []
       , filePackage = "a1b331fa-1539-49e5-bdc4-dc8a48e586d1"
       }
 headers:
-  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population&drilldowns=Nation&measures=Population
+  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population
 query: ?drilldowns=Nation&measures=Population
 status: 302
diff --git a/test/golden/file-package-without-varible-2.output.yaml b/test/golden/file-package-without-varible-2.output.yaml
index 5b09cd2..4c4ffcf 100644
--- a/test/golden/file-package-without-varible-2.output.yaml
+++ b/test/golden/file-package-without-varible-2.output.yaml
@@ -3,11 +3,11 @@ capture: |-
     FlatfileCapture
       { fileAbsoluteUrl =
           Just
-            "https://datausa.io/api/data?drilldowns=Nation&measures=Population&drilldowns=Nation&measures=Population"
+            "https://datausa.io/api/data?drilldowns=Nation&measures=Population"
       , fileVariables = fromList []
       , filePackage = "a1b331fa-1539-49e5-bdc4-dc8a48e586d1"
       }
 headers:
-  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population&drilldowns=Nation&measures=Population
+  Location: https://datausa.io/api/data?drilldowns=Nation&measures=Population
 query: ?drilldowns=Nation&measures=Population
 status: 302