diff --git a/VimR/MainWindowComponent.swift b/VimR/MainWindowComponent.swift
index c2089081..08bcb3ac 100644
--- a/VimR/MainWindowComponent.swift
+++ b/VimR/MainWindowComponent.swift
@@ -6,6 +6,7 @@
 import Cocoa
 import PureLayout
 import RxSwift
+import Swifter
 
 enum MainWindowAction {
 
@@ -109,6 +110,8 @@ class MainWindowComponent: WindowComponent,
 
   fileprivate let scrollFlow: EmbeddableComponent
 
+  fileprivate let httpServer: HttpServer;
+
   // MARK: - API
   var uuid: String {
     return self.neoVimView.uuid
@@ -141,6 +144,7 @@ class MainWindowComponent: WindowComponent,
        fileItemService: FileItemService,
        cwd: URL,
        urls: [URL] = [],
+       httpServer: HttpServer,
        initialData: PrefData)
   {
     self.neoVimView = NeoVimView(frame: CGRect.zero,
@@ -154,6 +158,8 @@ class MainWindowComponent: WindowComponent,
 
     self.scrollFlow = EmbeddableComponent(source: Observable.empty())
 
+    self.httpServer = httpServer
+
     super.init(source: source, nibName: MainWindowComponent.nibName)
 
     self.window.delegate = self
@@ -213,6 +219,7 @@ class MainWindowComponent: WindowComponent,
     let previewData = previewToolData.toolData as? PreviewComponent.PrefData ?? PreviewComponent.PrefData.default
     let preview = PreviewComponent(source: self.sink,
                                    scrollSource: self.scrollFlow.sink,
+                                   httpServer: self.httpServer,
                                    initialData: previewData)
     let previewConfig = WorkspaceTool.Config(title: "Preview",
                                              view: preview,
diff --git a/VimR/MainWindowManager.swift b/VimR/MainWindowManager.swift
index cf9d7ad3..369e50d0 100644
--- a/VimR/MainWindowManager.swift
+++ b/VimR/MainWindowManager.swift
@@ -5,6 +5,7 @@
 
 import Cocoa
 import RxSwift
+import Swifter
 
 enum MainWindowManagerAction {
 
@@ -19,10 +20,20 @@ class MainWindowManager: StandardFlow {
   fileprivate let fileItemService: FileItemService
   fileprivate var data: PrefData
 
+  fileprivate let httpServer = HttpServer() // TODO: WRONG: service-ify this!!!
+
   init(source: Observable<Any>, fileItemService: FileItemService, initialData: PrefData) {
     self.fileItemService = fileItemService
     self.data = initialData
 
+    let port = NetUtils.openPort()
+    NSLog("\(#function): opening a server on port \(port)")
+    do {
+      try self.httpServer.start(port)
+    } catch {
+      NSLog("ERROR \(#function): could not start the http server on port \(port)")
+    }
+
     super.init(source: source)
   }
 
@@ -31,6 +42,7 @@ class MainWindowManager: StandardFlow {
                                                   fileItemService: self.fileItemService,
                                                   cwd: cwd,
                                                   urls: urls,
+                                                  httpServer: self.httpServer,
                                                   initialData: self.data)
 
     self.mainWindowComponents[mainWindowComponent.uuid] = mainWindowComponent
@@ -60,6 +72,10 @@ class MainWindowManager: StandardFlow {
     return mainWindowComponent
   }
 
+  deinit {
+    self.httpServer.stop()
+  }
+
   func close(_ mainWindowComponent: MainWindowComponent, prefData: MainWindowPrefData) {
     // Save the tools settings of the last closed main window.
     // TODO: Think about a better time to save this.
diff --git a/VimR/MarkdownRenderer.swift b/VimR/MarkdownRenderer.swift
index c0b9bfac..de74cb7f 100644
--- a/VimR/MarkdownRenderer.swift
+++ b/VimR/MarkdownRenderer.swift
@@ -149,8 +149,8 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
   fileprivate var currentPreviewPosition = Position(row: 1, column: 1)
 
   fileprivate let uuid = UUID().uuidString
-  fileprivate var server = HttpServer()
-  fileprivate let port: in_port_t
+  fileprivate let httpServer: HttpServer
+  fileprivate let port: Int
   fileprivate let tempDir = URL(fileURLWithPath: NSTemporaryDirectory(), isDirectory: true)
 
   let identifier: String = MarkdownRenderer.identifier
@@ -171,7 +171,10 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
   let toolbar: NSView? = NSView(forAutoLayout: ())
   let menuItems: [NSMenuItem]?
 
-  init(source: Observable<Any>, scrollSource: Observable<Any>, initialData: PrefData) {
+  init(source: Observable<Any>, scrollSource: Observable<Any>, httpServer: HttpServer, initialData: PrefData) {
+    NSLog("\(#function) \(uuid)")
+    NSLog("\(#function) \(self.tempDir)")
+
     guard let templateUrl = Bundle.main.url(forResource: "template",
                                             withExtension: "html",
                                             subdirectory: "markdown")
@@ -183,17 +186,11 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
       preconditionFailure("ERROR Cannot load markdown template")
     }
 
-    self.server.GET["/\(MarkdownRenderer.serverPath)/github-markdown.css"] = shareFile(
+    self.httpServer = httpServer
+    self.httpServer.GET["/\(MarkdownRenderer.serverPath)/\(self.uuid)/github-markdown.css"] = shareFile(
       self.resourceBaesUrl.appendingPathComponent("github-markdown.css").path
     )
-
-    self.port = NetUtils.openPort()
-    NSLog("\(#function): opening a server on port \(port)")
-    do {
-      try self.server.start(port)
-    } catch {
-      NSLog("ERROR \(#function): could not start the http server on port \(self.port)")
-    }
+    self.port = (try? httpServer.port()) ?? 0
 
     self.template = template
 
@@ -257,7 +254,7 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
   }
 
   deinit {
-    self.server.stop()
+    try? FileManager.default.removeItem(at: self.htmlFileUrl())
   }
 
   func canRender(fileExtension: String) -> Bool {
@@ -388,7 +385,7 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
     }
 
     let html = filledTemplate(body: body, title: url.lastPathComponent)
-    let htmlFilePath = tempDir.appendingPathComponent("\(MarkdownRenderer.identifier).\(self.uuid).html").path
+    let htmlFilePath = self.htmlFileUrl().path
     do {
       try html.write(toFile: htmlFilePath, atomically: true, encoding: .utf8)
     } catch {
@@ -397,16 +394,22 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
       return
     }
 
-    self.server["/\(MarkdownRenderer.serverPath)/:path"] = shareFilesFromDirectory(url.deletingLastPathComponent().path)
-    self.server.GET["/\(MarkdownRenderer.serverPath)/index.html"] = shareFile(htmlFilePath)
+    self.httpServer["/\(MarkdownRenderer.serverPath)/\(self.uuid)/:path"] =
+      shareFilesFromDirectory(url.deletingLastPathComponent().path)
+
+    self.httpServer.GET["/\(MarkdownRenderer.serverPath)/\(self.uuid)/index.html"] = shareFile(htmlFilePath)
 
     let urlRequest = URLRequest(
-      url: URL(string: "http://localhost:\(self.port)/\(MarkdownRenderer.serverPath)/index.html")!
+      url: URL(string: "http://localhost:\(self.port)/\(MarkdownRenderer.serverPath)/\(self.uuid)/index.html")!
     )
     self.webview.load(urlRequest)
 
     self.flow.publish(event: PreviewRendererAction.view(renderer: self, view: self.webview))
   }
+
+  fileprivate func htmlFileUrl() -> URL {
+    return self.tempDir.appendingPathComponent("\(MarkdownRenderer.identifier).\(self.uuid).html")
+  }
 }
 
 // MARK: - Actions
diff --git a/VimR/PreviewComponent.swift b/VimR/PreviewComponent.swift
index b9b1cca0..fa8833ad 100644
--- a/VimR/PreviewComponent.swift
+++ b/VimR/PreviewComponent.swift
@@ -7,6 +7,7 @@ import Cocoa
 import RxSwift
 import PureLayout
 import WebKit
+import Swifter
 
 class PreviewComponent: NSView, ViewComponent, ToolDataHolder, WKNavigationDelegate {
 
@@ -112,6 +113,8 @@ class PreviewComponent: NSView, ViewComponent, ToolDataHolder, WKNavigationDeleg
     }
   }
 
+  fileprivate let httpServer: HttpServer
+
   required init?(coder: NSCoder) {
     fatalError("init(coder:) has not been implemented")
   }
@@ -137,14 +140,16 @@ class PreviewComponent: NSView, ViewComponent, ToolDataHolder, WKNavigationDeleg
     return self
   }
 
-  init(source: Observable<Any>, scrollSource: Observable<Any>, initialData: PrefData) {
+  init(source: Observable<Any>, scrollSource: Observable<Any>, httpServer: HttpServer, initialData: PrefData) {
     self.flow = EmbeddableComponent(source: source)
+    self.httpServer = httpServer
 
     self.baseUrl = self.previewService.baseUrl()
     let markdownData = initialData.rendererDatas[MarkdownRenderer.identifier] as? MarkdownRenderer.PrefData ??
                        MarkdownRenderer.PrefData.default
     self.markdownRenderer = MarkdownRenderer(source: self.flow.sink,
                                              scrollSource: scrollSource,
+                                             httpServer: self.httpServer,
                                              initialData: markdownData)
 
     self.renderers = [
@@ -231,7 +236,7 @@ class PreviewComponent: NSView, ViewComponent, ToolDataHolder, WKNavigationDeleg
       .throttle(1, latest: true, scheduler: self.scheduler)
       .filter { $0 is PreviewRendererAction }
       .map { $0 as! PreviewRendererAction }
-      .subscribe(onNext: { action in
+      .subscribe(onNext: { [unowned self] action in
         guard self.isOpen else {
           return
         }