diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp
index 2dcf0fb36fb6..1aa879981812 100644
--- a/clang-tools-extra/clangd/ClangdServer.cpp
+++ b/clang-tools-extra/clangd/ClangdServer.cpp
@@ -152,6 +152,9 @@ void ClangdServer::addDocument(PathRef File, llvm::StringRef Contents,
   Opts.ClangTidyOpts = tidy::ClangTidyOptions::getDefaults();
   if (ClangTidyOptProvider)
     Opts.ClangTidyOpts = ClangTidyOptProvider->getOptions(File);
+  // FIXME: cache this.
+  Opts.Style =
+      getFormatStyleForFile(File, Contents, FSProvider.getFileSystem().get());
   Opts.SuggestMissingIncludes = SuggestMissingIncludes;
   // FIXME: some build systems like Bazel will take time to preparing
   // environment to build the file, it would be nice if we could emit a
@@ -372,8 +375,7 @@ void ClangdServer::applyTweak(PathRef File, Range Sel, StringRef TweakID,
     auto A = prepareTweak(TweakID, *Selection);
     if (!A)
       return CB(A.takeError());
-    // FIXME: run formatter on top of resulting replacements.
-    return CB((*A)->apply(*Selection));
+    return CB((*A)->apply(*Selection, InpAST->Inputs.Opts.Style));
   };
   WorkScheduler.runWithAST(
       "ApplyTweak", File,
diff --git a/clang-tools-extra/clangd/ClangdUnit.cpp b/clang-tools-extra/clangd/ClangdUnit.cpp
index ffb96fbf6d29..cb7fae5ff306 100644
--- a/clang-tools-extra/clangd/ClangdUnit.cpp
+++ b/clang-tools-extra/clangd/ClangdUnit.cpp
@@ -309,9 +309,8 @@ ParsedAST::build(std::unique_ptr<CompilerInvocation> CI,
   llvm::Optional<IncludeFixer> FixIncludes;
   auto BuildDir = VFS->getCurrentWorkingDirectory();
   if (Opts.SuggestMissingIncludes && Index && !BuildDir.getError()) {
-    auto Style = getFormatStyleForFile(MainInput.getFile(), Content, VFS.get());
     auto Inserter = std::make_shared<IncludeInserter>(
-        MainInput.getFile(), Content, Style, BuildDir.get(),
+        MainInput.getFile(), Content, Opts.Style, BuildDir.get(),
         Clang->getPreprocessor().getHeaderSearchInfo());
     if (Preamble) {
       for (const auto &Inc : Preamble->Includes.MainFileIncludes)
diff --git a/clang-tools-extra/clangd/Compiler.h b/clang-tools-extra/clangd/Compiler.h
index 9466d8e2c086..2d5c1b3e44a7 100644
--- a/clang-tools-extra/clangd/Compiler.h
+++ b/clang-tools-extra/clangd/Compiler.h
@@ -17,6 +17,7 @@
 
 #include "../clang-tidy/ClangTidyOptions.h"
 #include "index/Index.h"
+#include "clang/Format/Format.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/PrecompiledPreamble.h"
@@ -38,6 +39,7 @@ public:
 struct ParseOptions {
   tidy::ClangTidyOptions ClangTidyOpts;
   bool SuggestMissingIncludes = false;
+  format::FormatStyle Style;
 };
 
 /// Information required to run clang, e.g. to parse AST or do code completion.
diff --git a/clang-tools-extra/clangd/SourceCode.cpp b/clang-tools-extra/clangd/SourceCode.cpp
index a4af1a9d7355..86146758a541 100644
--- a/clang-tools-extra/clangd/SourceCode.cpp
+++ b/clang-tools-extra/clangd/SourceCode.cpp
@@ -335,5 +335,14 @@ format::FormatStyle getFormatStyleForFile(llvm::StringRef File,
   return *Style;
 }
 
+llvm::Expected<tooling::Replacements>
+cleanupAndFormat(StringRef Code, const tooling::Replacements &Replaces,
+                 const format::FormatStyle &Style) {
+  auto CleanReplaces = cleanupAroundReplacements(Code, Replaces, Style);
+  if (!CleanReplaces)
+    return CleanReplaces;
+  return formatReplacements(Code, std::move(*CleanReplaces), Style);
+}
+
 } // namespace clangd
 } // namespace clang
diff --git a/clang-tools-extra/clangd/SourceCode.h b/clang-tools-extra/clangd/SourceCode.h
index 37b7b166a816..e6ce8c3be5da 100644
--- a/clang-tools-extra/clangd/SourceCode.h
+++ b/clang-tools-extra/clangd/SourceCode.h
@@ -144,6 +144,11 @@ format::FormatStyle getFormatStyleForFile(llvm::StringRef File,
                                           llvm::StringRef Content,
                                           llvm::vfs::FileSystem *FS);
 
+// Cleanup and format the given replacements.
+llvm::Expected<tooling::Replacements>
+cleanupAndFormat(StringRef Code, const tooling::Replacements &Replaces,
+                 const format::FormatStyle &Style);
+
 } // namespace clangd
 } // namespace clang
 #endif
diff --git a/clang-tools-extra/clangd/refactor/Tweak.cpp b/clang-tools-extra/clangd/refactor/Tweak.cpp
index 34634e64b6f9..6a3b090b80b0 100644
--- a/clang-tools-extra/clangd/refactor/Tweak.cpp
+++ b/clang-tools-extra/clangd/refactor/Tweak.cpp
@@ -46,6 +46,14 @@ Tweak::Selection::Selection(ParsedAST &AST, unsigned RangeBegin,
   Cursor = SM.getComposedLoc(SM.getMainFileID(), RangeBegin);
 }
 
+Expected<tooling::Replacements> Tweak::apply(const Selection &Sel,
+                                             const format::FormatStyle &Style) {
+  auto RawReplacements = execute(Sel);
+  if (!RawReplacements)
+    return RawReplacements;
+  return cleanupAndFormat(Sel.Code, *RawReplacements, Style);
+}
+
 std::vector<std::unique_ptr<Tweak>> prepareTweaks(const Tweak::Selection &S) {
   validateRegistry();
 
diff --git a/clang-tools-extra/clangd/refactor/Tweak.h b/clang-tools-extra/clangd/refactor/Tweak.h
index 35c3ce8a93c2..108e07e1b01d 100644
--- a/clang-tools-extra/clangd/refactor/Tweak.h
+++ b/clang-tools-extra/clangd/refactor/Tweak.h
@@ -22,6 +22,7 @@
 #include "ClangdUnit.h"
 #include "Protocol.h"
 #include "Selection.h"
+#include "clang/Format/Format.h"
 #include "clang/Tooling/Core/Replacement.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
@@ -47,7 +48,7 @@ public:
     ParsedAST &AST;
     /// A location of the cursor in the editor.
     SourceLocation Cursor;
-    // The AST nodes that were selected.
+    /// The AST nodes that were selected.
     SelectionTree ASTSelection;
     // FIXME: provide a way to get sources and ASTs for other files.
   };
@@ -63,13 +64,20 @@ public:
   /// should be moved into 'apply'.
   /// Returns true iff the action is available and apply() can be called on it.
   virtual bool prepare(const Selection &Sel) = 0;
-  /// Run the second stage of the action that would produce the actual changes.
+  /// Format and apply the actual changes generated from the second stage of the
+  /// action.
   /// EXPECTS: prepare() was called and returned true.
-  virtual Expected<tooling::Replacements> apply(const Selection &Sel) = 0;
+  Expected<tooling::Replacements> apply(const Selection &Sel,
+                                        const format::FormatStyle &Style);
   /// A one-line title of the action that should be shown to the users in the
   /// UI.
   /// EXPECTS: prepare() was called and returned true.
   virtual std::string title() const = 0;
+
+protected:
+  /// Run the second stage of the action that would produce the actual changes.
+  /// EXPECTS: prepare() was called and returned true.
+  virtual Expected<tooling::Replacements> execute(const Selection &Sel) = 0;
 };
 
 // All tweaks must be registered in the .cpp file next to their definition.
diff --git a/clang-tools-extra/clangd/refactor/tweaks/SwapIfBranches.cpp b/clang-tools-extra/clangd/refactor/tweaks/SwapIfBranches.cpp
index 9b0b72d94ca5..40dd69871506 100644
--- a/clang-tools-extra/clangd/refactor/tweaks/SwapIfBranches.cpp
+++ b/clang-tools-extra/clangd/refactor/tweaks/SwapIfBranches.cpp
@@ -37,9 +37,11 @@ public:
   const char *id() const override final;
 
   bool prepare(const Selection &Inputs) override;
-  Expected<tooling::Replacements> apply(const Selection &Inputs) override;
   std::string title() const override;
 
+protected:
+  Expected<tooling::Replacements> execute(const Selection &Inputs) override;
+
 private:
   const IfStmt *If = nullptr;
 };
@@ -60,7 +62,8 @@ bool SwapIfBranches::prepare(const Selection &Inputs) {
          dyn_cast_or_null<CompoundStmt>(If->getElse());
 }
 
-Expected<tooling::Replacements> SwapIfBranches::apply(const Selection &Inputs) {
+Expected<tooling::Replacements>
+SwapIfBranches::execute(const Selection &Inputs) {
   auto &Ctx = Inputs.AST.getASTContext();
   auto &SrcMgr = Ctx.getSourceManager();
 
diff --git a/clang-tools-extra/unittests/clangd/TweakTests.cpp b/clang-tools-extra/unittests/clangd/TweakTests.cpp
index baa60292e3df..a76d3aea800d 100644
--- a/clang-tools-extra/unittests/clangd/TweakTests.cpp
+++ b/clang-tools-extra/unittests/clangd/TweakTests.cpp
@@ -98,7 +98,7 @@ llvm::Expected<std::string> apply(StringRef ID, llvm::StringRef Input) {
   auto T = prepareTweak(ID, S);
   if (!T)
     return T.takeError();
-  auto Replacements = (*T)->apply(S);
+  auto Replacements = (*T)->apply(S, clang::format::getLLVMStyle());
   if (!Replacements)
     return Replacements.takeError();
   return applyAllReplacements(Code.code(), *Replacements);
@@ -127,12 +127,40 @@ TEST(TweakTest, SwapIfBranches) {
 
   llvm::StringLiteral Input = R"cpp(
     void test() {
-      ^if (true) { return 100; } else { continue; }
+      ^if (true) {
+        return 100;
+      } else {
+        continue;
+      }
     }
   )cpp";
   llvm::StringLiteral Output = R"cpp(
     void test() {
-      if (true) { continue; } else { return 100; }
+      if (true) {
+        continue;
+      } else {
+        return 100;
+      }
+    }
+  )cpp";
+  checkTransform(ID, Input, Output);
+
+  Input = R"cpp(
+    void test() {
+      ^if () {
+        return 100;
+      } else {
+        continue;
+      }
+    }
+  )cpp";
+  Output = R"cpp(
+    void test() {
+      if () {
+        continue;
+      } else {
+        return 100;
+      }
     }
   )cpp";
   checkTransform(ID, Input, Output);
@@ -144,7 +172,11 @@ TEST(TweakTest, SwapIfBranches) {
   )cpp";
   Output = R"cpp(
     void test() {
-      if () { continue; } else { return 100; }
+      if () {
+        continue;
+      } else {
+        return 100;
+      }
     }
   )cpp";
   checkTransform(ID, Input, Output);