diff --git a/.changeset/kind-rings-attend.md b/.changeset/kind-rings-attend.md
new file mode 100644
index 0000000..16c4abc
--- /dev/null
+++ b/.changeset/kind-rings-attend.md
@@ -0,0 +1,8 @@
+---
+"@rescript-relay-router-example/client-rendering": minor
+"@rescript-relay-router-example/express": minor
+"rescript-relay-router": minor
+"@rescript-relay-router/utils": minor
+---
+
+remove query param from URL when its value is default
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ca11f65..910bdd9 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -38,11 +38,6 @@ jobs:
       - name: Build all projects
         run: |
           yarn build
-      # Since we don't want to have generated code formatted in the router we regenerate
-      # the router code after formatting.
-      - name: Sync router code generation
-        run: |
-          yarn workspaces foreach --topological-dev run router:generate
       - name: git status
         id: git_status
         shell: bash
diff --git a/examples/client-rendering/package.json b/examples/client-rendering/package.json
index 9bf1619..2e3ed31 100644
--- a/examples/client-rendering/package.json
+++ b/examples/client-rendering/package.json
@@ -8,7 +8,7 @@
   "type": "module",
   "packageManager": "yarn@3.2.1",
   "scripts": {
-    "build": "run-s 'build:*'",
+    "build": "yarn router:generate && run-s 'build:*'",
     "build:relay": "rescript-relay-compiler",
     "build:rescript": "rescript build -with-deps",
     "build:vite": "vite build --outDir dist/client",
diff --git a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecodedExtra_route.res b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecodedExtra_route.res
index 03f6706..0e32601 100644
--- a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecodedExtra_route.res
+++ b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecodedExtra_route.res
@@ -79,7 +79,7 @@ let applyQueryParams = (
 
   
   queryParams->QueryParams.setParamArrayOpt(~key="statuses", ~value=newParams.statuses->Option.map(statuses => statuses->Array.map(statuses => statuses->TodoStatus.serialize)))
-  queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=newParams.statusWithDefault->TodoStatus.serialize)
+  queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=newParams.statusWithDefault == TodoStatus.defaultValue ? None : newParams.statusWithDefault->TodoStatus.serialize->Some)
   queryParams->QueryParams.setParamOpt(~key="byValue", ~value=newParams.byValue->Option.map(byValue => byValue))
 }
 
@@ -122,7 +122,7 @@ let makeLink = (~byStatusDecoded: TodoStatusPathParam.t, ~statuses: option<array
 
   switch statusWithDefault {
     | None => ()
-    | Some(statusWithDefault) => queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=statusWithDefault->TodoStatus.serialize)
+    | Some(statusWithDefault) => queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=statusWithDefault == TodoStatus.defaultValue ? None : statusWithDefault->TodoStatus.serialize->Some)
   }
 
   switch byValue {
diff --git a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded__Child_route.res b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded__Child_route.res
index d504709..ee6259e 100644
--- a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded__Child_route.res
+++ b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded__Child_route.res
@@ -79,7 +79,7 @@ let applyQueryParams = (
 
   
   queryParams->QueryParams.setParamArrayOpt(~key="statuses", ~value=newParams.statuses->Option.map(statuses => statuses->Array.map(statuses => statuses->TodoStatus.serialize)))
-  queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=newParams.statusWithDefault->TodoStatus.serialize)
+  queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=newParams.statusWithDefault == TodoStatus.defaultValue ? None : newParams.statusWithDefault->TodoStatus.serialize->Some)
   queryParams->QueryParams.setParamOpt(~key="byValue", ~value=newParams.byValue->Option.map(byValue => byValue))
 }
 
@@ -122,7 +122,7 @@ let makeLink = (~byStatusDecoded: TodoStatusPathParam.t, ~statuses: option<array
 
   switch statusWithDefault {
     | None => ()
-    | Some(statusWithDefault) => queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=statusWithDefault->TodoStatus.serialize)
+    | Some(statusWithDefault) => queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=statusWithDefault == TodoStatus.defaultValue ? None : statusWithDefault->TodoStatus.serialize->Some)
   }
 
   switch byValue {
diff --git a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded_route.res b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded_route.res
index 4b883f8..8eb1d00 100644
--- a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded_route.res
+++ b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatusDecoded_route.res
@@ -87,7 +87,7 @@ let applyQueryParams = (
 
   
   queryParams->QueryParams.setParamArrayOpt(~key="statuses", ~value=newParams.statuses->Option.map(statuses => statuses->Array.map(statuses => statuses->TodoStatus.serialize)))
-  queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=newParams.statusWithDefault->TodoStatus.serialize)
+  queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=newParams.statusWithDefault == TodoStatus.defaultValue ? None : newParams.statusWithDefault->TodoStatus.serialize->Some)
   queryParams->QueryParams.setParamOpt(~key="byValue", ~value=newParams.byValue->Option.map(byValue => byValue))
 }
 
@@ -130,7 +130,7 @@ let makeLink = (~byStatusDecoded: TodoStatusPathParam.t, ~statuses: option<array
 
   switch statusWithDefault {
     | None => ()
-    | Some(statusWithDefault) => queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=statusWithDefault->TodoStatus.serialize)
+    | Some(statusWithDefault) => queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=statusWithDefault == TodoStatus.defaultValue ? None : statusWithDefault->TodoStatus.serialize->Some)
   }
 
   switch byValue {
diff --git a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatus_route.res b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatus_route.res
index e303671..01113dc 100644
--- a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatus_route.res
+++ b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__ByStatus_route.res
@@ -79,7 +79,7 @@ let applyQueryParams = (
 
   
   queryParams->QueryParams.setParamArrayOpt(~key="statuses", ~value=newParams.statuses->Option.map(statuses => statuses->Array.map(statuses => statuses->TodoStatus.serialize)))
-  queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=newParams.statusWithDefault->TodoStatus.serialize)
+  queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=newParams.statusWithDefault == TodoStatus.defaultValue ? None : newParams.statusWithDefault->TodoStatus.serialize->Some)
   queryParams->QueryParams.setParamOpt(~key="byValue", ~value=newParams.byValue->Option.map(byValue => byValue))
 }
 
@@ -122,7 +122,7 @@ let makeLink = (~byStatus: [#"completed" | #"not-completed"], ~statuses: option<
 
   switch statusWithDefault {
     | None => ()
-    | Some(statusWithDefault) => queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=statusWithDefault->TodoStatus.serialize)
+    | Some(statusWithDefault) => queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=statusWithDefault == TodoStatus.defaultValue ? None : statusWithDefault->TodoStatus.serialize->Some)
   }
 
   switch byValue {
diff --git a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__Single_route.res b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__Single_route.res
index a3e2c1d..43f6b55 100644
--- a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__Single_route.res
+++ b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos__Single_route.res
@@ -91,7 +91,7 @@ let applyQueryParams = (
 
   
   queryParams->QueryParams.setParamArrayOpt(~key="statuses", ~value=newParams.statuses->Option.map(statuses => statuses->Array.map(statuses => statuses->TodoStatus.serialize)))
-  queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=newParams.statusWithDefault->TodoStatus.serialize)
+  queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=newParams.statusWithDefault == TodoStatus.defaultValue ? None : newParams.statusWithDefault->TodoStatus.serialize->Some)
   queryParams->QueryParams.setParamOpt(~key="byValue", ~value=newParams.byValue->Option.map(byValue => byValue))
   queryParams->QueryParams.setParamOpt(~key="showMore", ~value=newParams.showMore->Option.map(showMore => switch showMore { | true => "true" | false => "false" }))
 }
@@ -135,7 +135,7 @@ let makeLink = (~todoId: string, ~statuses: option<array<TodoStatus.t>>=?, ~stat
 
   switch statusWithDefault {
     | None => ()
-    | Some(statusWithDefault) => queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=statusWithDefault->TodoStatus.serialize)
+    | Some(statusWithDefault) => queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=statusWithDefault == TodoStatus.defaultValue ? None : statusWithDefault->TodoStatus.serialize->Some)
   }
 
   switch byValue {
diff --git a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos_route.res b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos_route.res
index bbc1fd6..c318e9a 100644
--- a/examples/client-rendering/src/routes/__generated__/Route__Root__Todos_route.res
+++ b/examples/client-rendering/src/routes/__generated__/Route__Root__Todos_route.res
@@ -81,7 +81,7 @@ let applyQueryParams = (
 
   
   queryParams->QueryParams.setParamArrayOpt(~key="statuses", ~value=newParams.statuses->Option.map(statuses => statuses->Array.map(statuses => statuses->TodoStatus.serialize)))
-  queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=newParams.statusWithDefault->TodoStatus.serialize)
+  queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=newParams.statusWithDefault == TodoStatus.defaultValue ? None : newParams.statusWithDefault->TodoStatus.serialize->Some)
   queryParams->QueryParams.setParamOpt(~key="byValue", ~value=newParams.byValue->Option.map(byValue => byValue))
 }
 
@@ -124,7 +124,7 @@ let makeLink = (~statuses: option<array<TodoStatus.t>>=?, ~statusWithDefault: op
 
   switch statusWithDefault {
     | None => ()
-    | Some(statusWithDefault) => queryParams->QueryParams.setParam(~key="statusWithDefault", ~value=statusWithDefault->TodoStatus.serialize)
+    | Some(statusWithDefault) => queryParams->QueryParams.setParamOpt(~key="statusWithDefault", ~value=statusWithDefault == TodoStatus.defaultValue ? None : statusWithDefault->TodoStatus.serialize->Some)
   }
 
   switch byValue {
diff --git a/examples/client-rendering/test/UrlEncodingDecoding.test.res b/examples/client-rendering/test/UrlEncodingDecoding.test.res
index 85167a1..7070daa 100644
--- a/examples/client-rendering/test/UrlEncodingDecoding.test.res
+++ b/examples/client-rendering/test/UrlEncodingDecoding.test.res
@@ -17,6 +17,11 @@ describe("makeLink", () => {
     let link = Routes.Root.Todos.Route.makeLink(~byValue="/incorrect value, for url")
     expect(link)->Expect.toBe("/todos?byValue=%2Fincorrect%20value%2C%20for%20url")
   })
+
+  test("should omit query param when value is default value", _t => {
+    let link = Routes.Root.Todos.Route.makeLink(~statusWithDefault=NotCompleted)
+    expect(link)->Expect.toBe("/todos")
+  })
 })
 
 describe("parsing", () => {
diff --git a/examples/express/package.json b/examples/express/package.json
index f859b3d..ca4d673 100644
--- a/examples/express/package.json
+++ b/examples/express/package.json
@@ -8,7 +8,7 @@
   "type": "module",
   "packageManager": "yarn@3.2.1",
   "scripts": {
-    "build": "run-s 'build:*'",
+    "build": "yarn router:generate && run-s 'build:*'",
     "build:relay": "rescript-relay-compiler",
     "build:rescript": "rescript build -with-deps",
     "build:vite": "run-s 'build:vite:*'",
diff --git a/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Codegen.res b/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Codegen.res
index a4fe4f0..7e479f7 100644
--- a/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Codegen.res
+++ b/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Codegen.res
@@ -100,6 +100,7 @@ let routePattern = "${route.path->RoutePath.toPattern}"
     queryParamSerializers->Array.forEach(((key, serializer, paramType)) => {
       let serializerStr = `queryParams->QueryParams.${switch paramType {
         | Array(_) => "setParamArray"
+        | CustomModule({required: true}) => "setParamOpt"
         | _ => "setParam"
         }}(~key="${key->SafeParam.getOriginalKey}", ~value=${serializer})`
 
@@ -231,7 +232,7 @@ let applyQueryParams = (
                 ~variableName=key,
               )})))`
           | CustomModule({required: true}) =>
-            `\n  queryParams->QueryParams.setParam(~key="${key}", ~value=${queryParam->Utils.QueryParams.toSerializer(
+            `\n  queryParams->QueryParams.setParamOpt(~key="${key}", ~value=${queryParam->Utils.QueryParams.toSerializer(
                 ~variableName=`newParams.${key}`,
               )})`
           | queryParam =>
diff --git a/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Utils.res b/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Utils.res
index 5025327..192fe7a 100644
--- a/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Utils.res
+++ b/packages/rescript-relay-router/cli/RescriptRelayRouterCli__Utils.res
@@ -85,6 +85,8 @@ module QueryParams = {
     | Boolean => `switch ${variableName} { | true => "true" | false => "false" }`
     | Int => `Int.toString(${variableName})`
     | Float => `Float.toString(${variableName})`
+    | CustomModule({moduleName, required: true}) =>
+      `${variableName} == ${moduleName}.defaultValue ? None : ${variableName}->${moduleName}.serialize->Some`
     | CustomModule({moduleName}) => `${variableName}->${moduleName}.serialize`
     | Array(inner) =>
       switch inner {