diff --git a/devtools/client/jsonview/converter-child.js b/devtools/client/jsonview/converter-child.js
index bf8eaa73ca38..560847a1055d 100644
--- a/devtools/client/jsonview/converter-child.js
+++ b/devtools/client/jsonview/converter-child.js
@@ -289,11 +289,8 @@ Converter.prototype = {
         break;
 
       case "save":
-        // The window ID is needed when the JSON Viewer is inside an iframe.
-        let windowID = win.QueryInterface(Ci.nsIInterfaceRequestor)
-          .getInterface(Ci.nsIDOMWindowUtils).outerWindowID;
         childProcessMessageManager.sendAsyncMessage(
-          "devtools:jsonview:save", {url: value, windowID: windowID});
+          "devtools:jsonview:save", value);
     }
   },
 
diff --git a/devtools/client/jsonview/json-viewer.js b/devtools/client/jsonview/json-viewer.js
index 979e127ee12f..b8208291a381 100644
--- a/devtools/client/jsonview/json-viewer.js
+++ b/devtools/client/jsonview/json-viewer.js
@@ -15,7 +15,6 @@ define(function (require, exports, module) {
   const headers = document.getElementById("headers");
 
   let jsonData;
-  let prettyURL;
 
   try {
     jsonData = JSON.parse(json.textContent);
@@ -46,10 +45,7 @@ define(function (require, exports, module) {
     },
 
     onSaveJson: function () {
-      if (input.prettified && !prettyURL) {
-        prettyURL = URL.createObjectURL(new Blob([input.jsonPretty]));
-      }
-      dispatchEvent("save", input.prettified ? prettyURL : null);
+      dispatchEvent("save", input.prettified ? input.jsonPretty : input.jsonText);
     },
 
     onCopyHeaders: function () {
diff --git a/devtools/client/jsonview/main.js b/devtools/client/jsonview/main.js
index b2bed7f333ff..4164ca00d58c 100644
--- a/devtools/client/jsonview/main.js
+++ b/devtools/client/jsonview/main.js
@@ -7,17 +7,11 @@
 
 "use strict";
 
-const { Cu, Cc, Ci } = require("chrome");
+const { Cu } = require("chrome");
 const Services = require("Services");
 
 const { XPCOMUtils } = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
 
-XPCOMUtils.defineLazyGetter(this, "chrome", function () {
-  return Cc["@mozilla.org/appshell/window-mediator;1"]
-    .getService(Ci.nsIWindowMediator)
-    .getMostRecentWindow("navigator:browser");
-});
-
 XPCOMUtils.defineLazyGetter(this, "JsonViewUtils", function () {
   return require("devtools/client/jsonview/utils");
 });
@@ -56,28 +50,9 @@ var JsonView = {
    * in the parent process.
    */
   onSave: function (message) {
-    let browser = chrome.gBrowser.selectedBrowser;
-    if (message.data.url === null) {
-      // Save original contents
-      chrome.saveBrowser(browser, false, message.data.windowID);
-    } else {
-      // The following code emulates saveBrowser, but:
-      // - Uses the given blob URL containing the custom contents to save.
-      // - Obtains the file name from the URL of the document, not the blob.
-      let persistable = browser.QueryInterface(Ci.nsIFrameLoaderOwner)
-        .frameLoader.QueryInterface(Ci.nsIWebBrowserPersistable);
-      persistable.startPersistence(message.data.windowID, {
-        onDocumentReady(doc) {
-          let uri = chrome.makeURI(doc.documentURI, doc.characterSet);
-          let filename = chrome.getDefaultFileName(undefined, uri, doc, null);
-          chrome.internalSave(message.data.url, doc, filename, null, doc.contentType,
-            false, null, null, null, doc, false, null, undefined);
-        },
-        onError(status) {
-          throw new Error("JSON Viewer's onSave failed in startPersistence");
-        }
-      });
-    }
+    JsonViewUtils.getTargetFile().then(file => {
+      JsonViewUtils.saveToFile(file, message.data);
+    }, () => {});
   }
 };
 
diff --git a/devtools/client/jsonview/utils.js b/devtools/client/jsonview/utils.js
index fce7a5b0ce8a..5c2bffe57067 100644
--- a/devtools/client/jsonview/utils.js
+++ b/devtools/client/jsonview/utils.js
@@ -6,9 +6,86 @@
 
 "use strict";
 
-const { Cu } = require("chrome");
+const { Cu, Cc, Ci } = require("chrome");
 const Services = require("Services");
 
+const OPEN_FLAGS = {
+  RDONLY: parseInt("0x01", 16),
+  WRONLY: parseInt("0x02", 16),
+  CREATE_FILE: parseInt("0x08", 16),
+  APPEND: parseInt("0x10", 16),
+  TRUNCATE: parseInt("0x20", 16),
+  EXCL: parseInt("0x80", 16)
+};
+
+let filePickerShown = false;
+
+/**
+ * Open File Save As dialog and let the user to pick proper file location.
+ */
+exports.getTargetFile = function () {
+  return new Promise((resolve, reject) => {
+    if (filePickerShown) {
+      reject(null);
+      return;
+    }
+
+    filePickerShown = true;
+
+    let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
+
+    let win = Services.wm.getMostRecentWindow("navigator:browser");
+    fp.init(win, null, Ci.nsIFilePicker.modeSave);
+    fp.appendFilter("JSON Files", "*.json; *.jsonp;");
+    fp.appendFilters(Ci.nsIFilePicker.filterText);
+    fp.appendFilters(Ci.nsIFilePicker.filterAll);
+    fp.filterIndex = 0;
+
+    fp.open(rv => {
+      filePickerShown = false;
+
+      if (rv == Ci.nsIFilePicker.returnOK || rv == Ci.nsIFilePicker.returnReplace) {
+        resolve(fp.file);
+      } else {
+        reject(null);
+      }
+    });
+  });
+};
+
+/**
+ * Save JSON to a file
+ */
+exports.saveToFile = function (file, jsonString) {
+  let foStream = Cc["@mozilla.org/network/file-output-stream;1"]
+    .createInstance(Ci.nsIFileOutputStream);
+
+  // write, create, truncate
+  let openFlags = OPEN_FLAGS.WRONLY | OPEN_FLAGS.CREATE_FILE |
+    OPEN_FLAGS.TRUNCATE;
+
+  let permFlags = parseInt("0666", 8);
+  foStream.init(file, openFlags, permFlags, 0);
+
+  let converter = Cc["@mozilla.org/intl/converter-output-stream;1"]
+    .createInstance(Ci.nsIConverterOutputStream);
+
+  converter.init(foStream, "UTF-8", 0, 0);
+
+  // The entire jsonString can be huge so, write the data in chunks.
+  let chunkLength = 1024 * 1204;
+  for (let i = 0; i <= jsonString.length; i++) {
+    let data = jsonString.substr(i, chunkLength + 1);
+    if (data) {
+      converter.writeString(data);
+    }
+    i = i + chunkLength;
+  }
+
+  // this closes foStream
+  converter.close();
+};
+
 /**
  * Get the current theme from preferences.
  */