diff --git a/app/controllers/api/users_controller.rb b/app/controllers/api/users_controller.rb
index d97e8774e..b4a2efc7c 100644
--- a/app/controllers/api/users_controller.rb
+++ b/app/controllers/api/users_controller.rb
@@ -9,9 +9,15 @@ module Api
     around_action :api_call_handle_error
     before_action :lookup_user_by_id, :only => [:show]
 
+    before_action :set_request_formats, :except => [:gpx_files]
+
     def show
       if @user.visible?
-        render :content_type => "text/xml"
+        # Render the result
+        respond_to do |format|
+          format.xml
+          format.json
+        end
       else
         head :gone
       end
@@ -19,7 +25,11 @@ module Api
 
     def details
       @user = current_user
-      render :action => :show, :content_type => "text/xml"
+      # Render the result
+      respond_to do |format|
+        format.xml { render :show }
+        format.json { render :show }
+      end
     end
 
     def index
@@ -31,7 +41,11 @@ module Api
 
       @users = User.visible.find(ids)
 
-      render :content_type => "text/xml"
+      # Render the result
+      respond_to do |format|
+        format.xml
+        format.json
+      end
     end
 
     def gpx_files
diff --git a/app/views/api/users/_user.json.jbuilder b/app/views/api/users/_user.json.jbuilder
new file mode 100644
index 000000000..d89b42bef
--- /dev/null
+++ b/app/views/api/users/_user.json.jbuilder
@@ -0,0 +1,69 @@
+json.user do
+  json.id user.id
+  json.display_name user.display_name
+  json.account_created user.creation_time.xmlschema
+  json.description user.description if user.description
+
+  if current_user && current_user == user
+    json.contributor_terms do
+      json.agreed user.terms_agreed.present?
+      json.pd user.consider_pd
+    end
+  else
+    json.contributor_terms do
+      json.agreed user.terms_agreed.present?
+    end
+  end
+
+  json.img do
+    json.href user_image_url(user) if user.avatar.attached? || user.image_use_gravatar
+  end
+
+  json.roles do
+    json.array! user.roles.map(&:role)
+  end
+
+  json.changesets do
+    json.count user.changesets.size
+  end
+
+  json.traces do
+    json.count user.traces.size
+  end
+
+  json.blocks do
+    json.received do
+      json.count user.blocks.size
+      json.active user.blocks.active.size
+    end
+
+    if user.moderator?
+      json.issued do
+        json.count user.blocks_created.size
+        json.active user.blocks_created.active.size
+      end
+    end
+  end
+
+  if current_user && current_user == user
+    if user.home_lat && user.home_lon
+      json.home do
+        json.lat user.home_lat
+        json.lon user.home_lon
+        json.zoom user.home_zoom
+      end
+    end
+
+    json.languages user.languages if user.languages?
+
+    json.messages do
+      json.received do
+        json.count user.messages.size
+        json.unread user.new_messages.size
+      end
+      json.sent do
+        json.count user.sent_messages.size
+      end
+    end
+  end
+end
diff --git a/app/views/api/users/_user.builder b/app/views/api/users/_user.xml.builder
similarity index 100%
rename from app/views/api/users/_user.builder
rename to app/views/api/users/_user.xml.builder
diff --git a/app/views/api/users/index.json.jbuilder b/app/views/api/users/index.json.jbuilder
new file mode 100644
index 000000000..efc905cfe
--- /dev/null
+++ b/app/views/api/users/index.json.jbuilder
@@ -0,0 +1,3 @@
+json.users(@users) do |user|
+  json.partial! user
+end
diff --git a/app/views/api/users/index.builder b/app/views/api/users/index.xml.builder
similarity index 100%
rename from app/views/api/users/index.builder
rename to app/views/api/users/index.xml.builder
diff --git a/app/views/api/users/show.json.jbuilder b/app/views/api/users/show.json.jbuilder
new file mode 100644
index 000000000..51a85380c
--- /dev/null
+++ b/app/views/api/users/show.json.jbuilder
@@ -0,0 +1 @@
+json.partial! @user
diff --git a/app/views/api/users/show.builder b/app/views/api/users/show.xml.builder
similarity index 100%
rename from app/views/api/users/show.builder
rename to app/views/api/users/show.xml.builder
diff --git a/test/controllers/api/users_controller_test.rb b/test/controllers/api/users_controller_test.rb
index 7ebe50d7b..5ce30d6a6 100644
--- a/test/controllers/api/users_controller_test.rb
+++ b/test/controllers/api/users_controller_test.rb
@@ -9,10 +9,18 @@ module Api
         { :path => "/api/0.6/user/1", :method => :get },
         { :controller => "api/users", :action => "show", :id => "1" }
       )
+      assert_routing(
+        { :path => "/api/0.6/user/1.json", :method => :get },
+        { :controller => "api/users", :action => "show", :id => "1", :format => "json" }
+      )
       assert_routing(
         { :path => "/api/0.6/user/details", :method => :get },
         { :controller => "api/users", :action => "details" }
       )
+      assert_routing(
+        { :path => "/api/0.6/user/details.json", :method => :get },
+        { :controller => "api/users", :action => "details", :format => "json" }
+      )
       assert_routing(
         { :path => "/api/0.6/user/gpx_files", :method => :get },
         { :controller => "api/users", :action => "gpx_files" }
@@ -21,6 +29,10 @@ module Api
         { :path => "/api/0.6/users", :method => :get },
         { :controller => "api/users", :action => "index" }
       )
+      assert_routing(
+        { :path => "/api/0.6/users.json", :method => :get },
+        { :controller => "api/users", :action => "index", :format => "json" }
+      )
     end
 
     def test_show
@@ -28,7 +40,7 @@ module Api
       # check that a visible user is returned properly
       get api_user_path(:id => user.id)
       assert_response :success
-      assert_equal "text/xml", response.media_type
+      assert_equal "application/xml", response.media_type
 
       # check the data that is returned
       assert_select "description", :count => 1, :text => "test"
@@ -69,6 +81,15 @@ module Api
       # check that a non-existent user is not returned
       get api_user_path(:id => 0)
       assert_response :not_found
+
+      # check that a visible user is returned properly in json
+      get api_user_path(:id => user.id, :format => "json")
+      assert_response :success
+      assert_equal "application/json", response.media_type
+
+      js = ActiveSupport::JSON.decode(@response.body)
+      assert_not_nil js
+      assert_equal user.id, js["user"]["id"]
     end
 
     def test_details
@@ -84,7 +105,7 @@ module Api
       auth_header = basic_authorization_header user.email, "test"
       get user_details_path, :headers => auth_header
       assert_response :success
-      assert_equal "text/xml", response.media_type
+      assert_equal "application/xml", response.media_type
 
       # check the data that is returned
       assert_select "description", :count => 1, :text => "test"
@@ -130,16 +151,25 @@ module Api
 
       get api_users_path(:users => user1.id)
       assert_response :success
-      assert_equal "text/xml", response.media_type
+      assert_equal "application/xml", response.media_type
       assert_select "user", :count => 1 do
         assert_select "user[id='#{user1.id}']", :count => 1
         assert_select "user[id='#{user2.id}']", :count => 0
         assert_select "user[id='#{user3.id}']", :count => 0
       end
 
+      # Test json
+      get api_users_path(:users => user1.id, :format => "json")
+      assert_response :success
+      assert_equal "application/json", response.media_type
+
+      js = ActiveSupport::JSON.decode(@response.body)
+      assert_not_nil js
+      assert_equal 1, js["users"].count
+
       get api_users_path(:users => user2.id)
       assert_response :success
-      assert_equal "text/xml", response.media_type
+      assert_equal "application/xml", response.media_type
       assert_select "user", :count => 1 do
         assert_select "user[id='#{user1.id}']", :count => 0
         assert_select "user[id='#{user2.id}']", :count => 1
@@ -148,7 +178,7 @@ module Api
 
       get api_users_path(:users => "#{user1.id},#{user3.id}")
       assert_response :success
-      assert_equal "text/xml", response.media_type
+      assert_equal "application/xml", response.media_type
       assert_select "user", :count => 2 do
         assert_select "user[id='#{user1.id}']", :count => 1
         assert_select "user[id='#{user2.id}']", :count => 0