diff --git a/app/controllers/account/entropies_controller.rb b/app/controllers/account/entropies_controller.rb
index 9876e99d8..7290c1e4e 100644
--- a/app/controllers/account/entropies_controller.rb
+++ b/app/controllers/account/entropies_controller.rb
@@ -3,7 +3,11 @@ class Account::EntropiesController < ApplicationController
 
   def update
     Current.account.entropy.update!(entropy_params)
-    redirect_to account_settings_path, notice: "Account updated"
+
+    respond_to do |format|
+      format.html { redirect_to account_settings_path, notice: "Account updated" }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/account/exports_controller.rb b/app/controllers/account/exports_controller.rb
index dbe0a11c1..32fb5bd42 100644
--- a/app/controllers/account/exports_controller.rb
+++ b/app/controllers/account/exports_controller.rb
@@ -6,11 +6,20 @@ class Account::ExportsController < ApplicationController
   CURRENT_EXPORT_LIMIT = 10
 
   def show
+    respond_to do |format|
+      format.html
+      format.json { @export ? render(:show) : head(:not_found) }
+    end
   end
 
   def create
-    Current.account.exports.create!(user: Current.user).build_later
-    redirect_to account_settings_path, notice: "Export started. You'll receive an email when it's ready."
+    @export = Current.account.exports.create!(user: Current.user)
+    @export.build_later
+
+    respond_to do |format|
+      format.html { redirect_to account_settings_path, notice: "Export started. You'll receive an email when it's ready." }
+      format.json { render :show, status: :created }
+    end
   end
 
   private
@@ -23,6 +32,7 @@ class Account::ExportsController < ApplicationController
     end
 
     def set_export
-      @export = Current.account.exports.completed.find_by(id: params[:id], user: Current.user)
+      scope = request.format.json? ? Current.account.exports : Current.account.exports.completed
+      @export = scope.find_by(id: params[:id], user: Current.user)
     end
 end
diff --git a/app/controllers/account/join_codes_controller.rb b/app/controllers/account/join_codes_controller.rb
index 217ee603c..3df9552db 100644
--- a/app/controllers/account/join_codes_controller.rb
+++ b/app/controllers/account/join_codes_controller.rb
@@ -1,4 +1,6 @@
 class Account::JoinCodesController < ApplicationController
+  wrap_parameters :account_join_code
+
   before_action :set_join_code
   before_action :ensure_admin, only: %i[ update destroy ]
 
@@ -10,15 +12,25 @@ class Account::JoinCodesController < ApplicationController
 
   def update
     if @join_code.update(join_code_params)
-      redirect_to account_join_code_path
+      respond_to do |format|
+        format.html { redirect_to account_join_code_path }
+        format.json { head :no_content }
+      end
     else
-      render :edit, status: :unprocessable_entity
+      respond_to do |format|
+        format.html { render :edit, status: :unprocessable_entity }
+        format.json { render json: @join_code.errors, status: :unprocessable_entity }
+      end
     end
   end
 
   def destroy
     @join_code.reset
-    redirect_to account_join_code_path
+
+    respond_to do |format|
+      format.html { redirect_to account_join_code_path }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/account/settings_controller.rb b/app/controllers/account/settings_controller.rb
index 27f47ab99..6201ca656 100644
--- a/app/controllers/account/settings_controller.rb
+++ b/app/controllers/account/settings_controller.rb
@@ -1,4 +1,6 @@
 class Account::SettingsController < ApplicationController
+  wrap_parameters :account
+
   before_action :ensure_admin, only: :update
   before_action :set_account
 
@@ -8,7 +10,11 @@ class Account::SettingsController < ApplicationController
 
   def update
     @account.update!(account_params)
-    redirect_to account_settings_path
+
+    respond_to do |format|
+      format.html { redirect_to account_settings_path }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/boards/columns_controller.rb b/app/controllers/boards/columns_controller.rb
index 4b71e7f3e..a3cf867ea 100644
--- a/app/controllers/boards/columns_controller.rb
+++ b/app/controllers/boards/columns_controller.rb
@@ -18,7 +18,7 @@ class Boards::ColumnsController < ApplicationController
 
     respond_to do |format|
       format.turbo_stream
-      format.json { head :created, location: board_column_path(@board, @column, format: :json) }
+      format.json { render :show, status: :created, location: board_column_path(@board, @column, format: :json) }
     end
   end
 
diff --git a/app/controllers/boards/entropies_controller.rb b/app/controllers/boards/entropies_controller.rb
index e42631eaf..557adb2d9 100644
--- a/app/controllers/boards/entropies_controller.rb
+++ b/app/controllers/boards/entropies_controller.rb
@@ -1,10 +1,17 @@
 class Boards::EntropiesController < ApplicationController
+  wrap_parameters :board
+
   include BoardScoped
 
   before_action :ensure_permission_to_admin_board
 
   def update
     @board.update!(entropy_params)
+
+    respond_to do |format|
+      format.turbo_stream
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/boards/involvements_controller.rb b/app/controllers/boards/involvements_controller.rb
index a904f2989..271b50262 100644
--- a/app/controllers/boards/involvements_controller.rb
+++ b/app/controllers/boards/involvements_controller.rb
@@ -3,5 +3,11 @@ class Boards::InvolvementsController < ApplicationController
 
   def update
     @board.access_for(Current.user).update!(involvement: params[:involvement])
+
+    respond_to do |format|
+      format.html
+      format.turbo_stream
+      format.json { head :no_content }
+    end
   end
 end
diff --git a/app/controllers/boards_controller.rb b/app/controllers/boards_controller.rb
index 604938deb..1e93a5758 100644
--- a/app/controllers/boards_controller.rb
+++ b/app/controllers/boards_controller.rb
@@ -26,7 +26,7 @@ class BoardsController < ApplicationController
 
     respond_to do |format|
       format.html { redirect_to board_path(@board) }
-      format.json { head :created, location: board_path(@board, format: :json) }
+      format.json { render :show, status: :created, location: board_path(@board, format: :json) }
     end
   end
 
diff --git a/app/controllers/cards/comments/reactions_controller.rb b/app/controllers/cards/comments/reactions_controller.rb
index 0c822360e..32ca9f2f8 100644
--- a/app/controllers/cards/comments/reactions_controller.rb
+++ b/app/controllers/cards/comments/reactions_controller.rb
@@ -22,7 +22,7 @@ class Cards::Comments::ReactionsController < ApplicationController
 
     respond_to do |format|
       format.turbo_stream { render "reactions/create" }
-      format.json { head :created }
+      format.json { render "reactions/show", status: :created }
     end
   end
 
diff --git a/app/controllers/cards/comments_controller.rb b/app/controllers/cards/comments_controller.rb
index f2b318813..6a377bc2c 100644
--- a/app/controllers/cards/comments_controller.rb
+++ b/app/controllers/cards/comments_controller.rb
@@ -14,7 +14,7 @@ class Cards::CommentsController < ApplicationController
 
     respond_to do |format|
       format.turbo_stream
-      format.json { head :created, location: card_comment_path(@card, @comment, format: :json) }
+      format.json { render :show, status: :created, location: card_comment_path(@card, @comment, format: :json) }
     end
   end
 
diff --git a/app/controllers/cards/publishes_controller.rb b/app/controllers/cards/publishes_controller.rb
index a0378eec3..a544e6979 100644
--- a/app/controllers/cards/publishes_controller.rb
+++ b/app/controllers/cards/publishes_controller.rb
@@ -4,11 +4,17 @@ class Cards::PublishesController < ApplicationController
   def create
     @card.publish
 
-    if add_another_param?
-      card = @board.cards.create!(status: :drafted)
-      redirect_to card_draft_path(card), notice: "Card added"
-    else
-      redirect_to @card.board
+    respond_to do |format|
+      format.html do
+        if add_another_param?
+          card = @board.cards.create!(status: :drafted)
+          redirect_to card_draft_path(card), notice: "Card added"
+        else
+          redirect_to @card.board
+        end
+      end
+
+      format.json { head :created }
     end
   end
 
diff --git a/app/controllers/cards/reactions_controller.rb b/app/controllers/cards/reactions_controller.rb
index 4105a4121..4f19a1c64 100644
--- a/app/controllers/cards/reactions_controller.rb
+++ b/app/controllers/cards/reactions_controller.rb
@@ -21,7 +21,7 @@ class Cards::ReactionsController < ApplicationController
 
     respond_to do |format|
       format.turbo_stream { render "reactions/create" }
-      format.json { head :created }
+      format.json { render "reactions/show", status: :created }
     end
   end
 
diff --git a/app/controllers/cards/readings_controller.rb b/app/controllers/cards/readings_controller.rb
index 75fdbac19..4b71272f8 100644
--- a/app/controllers/cards/readings_controller.rb
+++ b/app/controllers/cards/readings_controller.rb
@@ -4,11 +4,21 @@ class Cards::ReadingsController < ApplicationController
   def create
     @notification = @card.read_by(Current.user)
     record_board_access
+
+    respond_to do |format|
+      format.turbo_stream
+      format.json { head :created }
+    end
   end
 
   def destroy
     @notification = @card.unread_by(Current.user)
     record_board_access
+
+    respond_to do |format|
+      format.turbo_stream
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/cards/steps_controller.rb b/app/controllers/cards/steps_controller.rb
index 0b788fe36..387dd8e23 100644
--- a/app/controllers/cards/steps_controller.rb
+++ b/app/controllers/cards/steps_controller.rb
@@ -3,12 +3,16 @@ class Cards::StepsController < ApplicationController
 
   before_action :set_step, only: %i[ show edit update destroy ]
 
+  def index
+    fresh_when etag: @card.steps
+  end
+
   def create
     @step = @card.steps.create!(step_params)
 
     respond_to do |format|
       format.turbo_stream
-      format.json { head :created, location: card_step_path(@card, @step, format: :json) }
+      format.json { render :show, status: :created, location: card_step_path(@card, @step, format: :json) }
     end
   end
 
diff --git a/app/controllers/cards_controller.rb b/app/controllers/cards_controller.rb
index e007527b8..482d2ff78 100644
--- a/app/controllers/cards_controller.rb
+++ b/app/controllers/cards_controller.rb
@@ -18,8 +18,8 @@ class CardsController < ApplicationController
       end
 
       format.json do
-        card = @board.cards.create! card_params.merge(creator: Current.user, status: "published")
-        head :created, location: card_path(card, format: :json)
+        @card = @board.cards.create! card_params.merge(creator: Current.user, status: "published")
+        render :show, status: :created, location: card_path(@card, format: :json)
       end
     end
   end
diff --git a/app/controllers/columns/left_positions_controller.rb b/app/controllers/columns/left_positions_controller.rb
index 7161c093f..78e0c0c80 100644
--- a/app/controllers/columns/left_positions_controller.rb
+++ b/app/controllers/columns/left_positions_controller.rb
@@ -4,5 +4,10 @@ class Columns::LeftPositionsController < ApplicationController
   def create
     @left_column = @column.left_column
     @column.move_left
+
+    respond_to do |format|
+      format.turbo_stream
+      format.json { head :created }
+    end
   end
 end
diff --git a/app/controllers/columns/right_positions_controller.rb b/app/controllers/columns/right_positions_controller.rb
index d43beb662..5d9cc37f9 100644
--- a/app/controllers/columns/right_positions_controller.rb
+++ b/app/controllers/columns/right_positions_controller.rb
@@ -4,5 +4,10 @@ class Columns::RightPositionsController < ApplicationController
   def create
     @right_column = @column.right_column
     @column.move_right
+
+    respond_to do |format|
+      format.turbo_stream
+      format.json { head :created }
+    end
   end
 end
diff --git a/app/controllers/my/access_tokens_controller.rb b/app/controllers/my/access_tokens_controller.rb
index 82cd93842..c9fcf38c3 100644
--- a/app/controllers/my/access_tokens_controller.rb
+++ b/app/controllers/my/access_tokens_controller.rb
@@ -1,4 +1,6 @@
 class My::AccessTokensController < ApplicationController
+  skip_before_action :require_account
+
   def index
     @access_tokens = my_access_tokens.order(created_at: :desc)
   end
@@ -24,14 +26,19 @@ class My::AccessTokensController < ApplicationController
 
       format.json do
         render status: :created, json: \
-          { token: access_token.token, description: access_token.description, permission: access_token.permission }
+          { id: access_token.id, token: access_token.token, description: access_token.description,
+            permission: access_token.permission, created_at: access_token.created_at.utc }
       end
     end
   end
 
   def destroy
     my_access_tokens.find(params[:id]).destroy!
-    redirect_to my_access_tokens_path
+
+    respond_to do |format|
+      format.html { redirect_to my_access_tokens_path }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/notifications/settings_controller.rb b/app/controllers/notifications/settings_controller.rb
index c4aab7f69..252abec2e 100644
--- a/app/controllers/notifications/settings_controller.rb
+++ b/app/controllers/notifications/settings_controller.rb
@@ -1,4 +1,6 @@
 class Notifications::SettingsController < ApplicationController
+  wrap_parameters :user_settings
+
   before_action :set_settings
 
   def show
@@ -7,7 +9,11 @@ class Notifications::SettingsController < ApplicationController
 
   def update
     @settings.update!(settings_params)
-    redirect_to notifications_settings_path, notice: "Settings updated"
+
+    respond_to do |format|
+      format.html { redirect_to notifications_settings_path, notice: "Settings updated" }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/searches_controller.rb b/app/controllers/searches_controller.rb
index b1ec5a0d2..70dfa4d4d 100644
--- a/app/controllers/searches_controller.rb
+++ b/app/controllers/searches_controller.rb
@@ -5,10 +5,22 @@ class SearchesController < ApplicationController
     @query = params[:q].blank? ? nil : params[:q]
 
     if card = Current.user.accessible_cards.find_by_id(@query)
-      @card = card
+      respond_to do |format|
+        format.html { @card = card }
+        format.json { set_page_and_extract_portion_from Current.user.accessible_cards.where(id: card.id) }
+      end
     else
-      set_page_and_extract_portion_from Current.user.search(@query)
-      @recent_search_queries = Current.user.search_queries.order(updated_at: :desc).limit(10)
+      respond_to do |format|
+        format.html do
+          set_page_and_extract_portion_from Current.user.search(@query)
+          @recent_search_queries = Current.user.search_queries.order(updated_at: :desc).limit(10)
+        end
+
+        format.json do
+          set_page_and_extract_portion_from \
+            Current.user.accessible_cards.mentioning(@query, user: Current.user).distinct.latest.preloaded
+        end
+      end
     end
   end
 end
diff --git a/app/controllers/users/avatars_controller.rb b/app/controllers/users/avatars_controller.rb
index 55d8f06dd..544398331 100644
--- a/app/controllers/users/avatars_controller.rb
+++ b/app/controllers/users/avatars_controller.rb
@@ -16,7 +16,11 @@ class Users::AvatarsController < ApplicationController
 
   def destroy
     @user.avatar.destroy
-    redirect_to @user
+
+    respond_to do |format|
+      format.html { redirect_to @user }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/users/push_subscriptions_controller.rb b/app/controllers/users/push_subscriptions_controller.rb
index b511a6b19..91b47264c 100644
--- a/app/controllers/users/push_subscriptions_controller.rb
+++ b/app/controllers/users/push_subscriptions_controller.rb
@@ -5,12 +5,21 @@ class Users::PushSubscriptionsController < ApplicationController
   end
 
   def create
-    @push_subscriptions.create_with(user_agent: request.user_agent).create_or_find_by!(push_subscription_params)
+    subscription = @push_subscriptions.create_with(user_agent: request.user_agent).create_or_find_by!(push_subscription_params)
+
+    respond_to do |format|
+      format.html { head :no_content }
+      format.json { head :created }
+    end
   end
 
   def destroy
     @push_subscriptions.destroy_by(id: params[:id])
-    redirect_to user_push_subscriptions_url
+
+    respond_to do |format|
+      format.html { redirect_to user_push_subscriptions_url }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/controllers/users/roles_controller.rb b/app/controllers/users/roles_controller.rb
index 711308d13..fb11d4e08 100644
--- a/app/controllers/users/roles_controller.rb
+++ b/app/controllers/users/roles_controller.rb
@@ -1,10 +1,16 @@
 class Users::RolesController < ApplicationController
+  wrap_parameters :user
+
   before_action :set_user
   before_action :ensure_permission_to_administer_user
 
   def update
     @user.update!(role_params)
-    redirect_to account_settings_path
+
+    respond_to do |format|
+      format.html { redirect_to account_settings_path }
+      format.json { head :no_content }
+    end
   end
 
   private
diff --git a/app/views/account/exports/show.json.jbuilder b/app/views/account/exports/show.json.jbuilder
new file mode 100644
index 000000000..2bd9e3d60
--- /dev/null
+++ b/app/views/account/exports/show.json.jbuilder
@@ -0,0 +1,6 @@
+json.(@export, :id, :status)
+json.created_at @export.created_at.utc
+
+if @export.completed? && @export.file.attached?
+  json.download_url rails_blob_url(@export.file, disposition: "attachment")
+end
diff --git a/app/views/account/join_codes/show.json.jbuilder b/app/views/account/join_codes/show.json.jbuilder
new file mode 100644
index 000000000..559e7b6c2
--- /dev/null
+++ b/app/views/account/join_codes/show.json.jbuilder
@@ -0,0 +1,3 @@
+json.(@join_code, :code, :usage_count, :usage_limit)
+json.url join_url(code: @join_code.code, script_name: Current.account.slug)
+json.active !!@join_code.active?
diff --git a/app/views/account/settings/show.json.jbuilder b/app/views/account/settings/show.json.jbuilder
new file mode 100644
index 000000000..9a62dabc6
--- /dev/null
+++ b/app/views/account/settings/show.json.jbuilder
@@ -0,0 +1 @@
+json.(Current.account, :name)
diff --git a/app/views/boards/columns/closeds/show.json.jbuilder b/app/views/boards/columns/closeds/show.json.jbuilder
new file mode 100644
index 000000000..c1dc1dff1
--- /dev/null
+++ b/app/views/boards/columns/closeds/show.json.jbuilder
@@ -0,0 +1 @@
+json.array! @page.records, partial: "cards/card", as: :card
diff --git a/app/views/boards/columns/not_nows/show.json.jbuilder b/app/views/boards/columns/not_nows/show.json.jbuilder
new file mode 100644
index 000000000..c1dc1dff1
--- /dev/null
+++ b/app/views/boards/columns/not_nows/show.json.jbuilder
@@ -0,0 +1 @@
+json.array! @page.records, partial: "cards/card", as: :card
diff --git a/app/views/boards/columns/streams/show.json.jbuilder b/app/views/boards/columns/streams/show.json.jbuilder
new file mode 100644
index 000000000..c1dc1dff1
--- /dev/null
+++ b/app/views/boards/columns/streams/show.json.jbuilder
@@ -0,0 +1 @@
+json.array! @page.records, partial: "cards/card", as: :card
diff --git a/app/views/cards/steps/index.json.jbuilder b/app/views/cards/steps/index.json.jbuilder
new file mode 100644
index 000000000..087790175
--- /dev/null
+++ b/app/views/cards/steps/index.json.jbuilder
@@ -0,0 +1 @@
+json.array! @card.steps, partial: "cards/steps/step", as: :step
diff --git a/app/views/my/access_tokens/_access_token.json.jbuilder b/app/views/my/access_tokens/_access_token.json.jbuilder
new file mode 100644
index 000000000..3e0a08084
--- /dev/null
+++ b/app/views/my/access_tokens/_access_token.json.jbuilder
@@ -0,0 +1,2 @@
+json.(access_token, :id, :description, :permission)
+json.created_at access_token.created_at.utc
diff --git a/app/views/my/access_tokens/index.json.jbuilder b/app/views/my/access_tokens/index.json.jbuilder
new file mode 100644
index 000000000..4abdba5f7
--- /dev/null
+++ b/app/views/my/access_tokens/index.json.jbuilder
@@ -0,0 +1 @@
+json.array! @access_tokens, partial: "my/access_tokens/access_token", as: :access_token
diff --git a/app/views/notifications/settings/show.json.jbuilder b/app/views/notifications/settings/show.json.jbuilder
new file mode 100644
index 000000000..6eaea0893
--- /dev/null
+++ b/app/views/notifications/settings/show.json.jbuilder
@@ -0,0 +1 @@
+json.bundle_email_frequency Current.user.settings.bundle_email_frequency
diff --git a/app/views/reactions/show.json.jbuilder b/app/views/reactions/show.json.jbuilder
new file mode 100644
index 000000000..a61ed5902
--- /dev/null
+++ b/app/views/reactions/show.json.jbuilder
@@ -0,0 +1 @@
+json.partial! "reactions/reaction", reaction: @reaction
diff --git a/app/views/searches/show.json.jbuilder b/app/views/searches/show.json.jbuilder
new file mode 100644
index 000000000..c1dc1dff1
--- /dev/null
+++ b/app/views/searches/show.json.jbuilder
@@ -0,0 +1 @@
+json.array! @page.records, partial: "cards/card", as: :card
diff --git a/test/controllers/accounts/entropies_controller_test.rb b/test/controllers/accounts/entropies_controller_test.rb
index ef23851de..5903ed7d0 100644
--- a/test/controllers/accounts/entropies_controller_test.rb
+++ b/test/controllers/accounts/entropies_controller_test.rb
@@ -13,6 +13,13 @@ class Account::EntropiesControllerTest < ActionDispatch::IntegrationTest
     assert_redirected_to account_settings_path
   end
 
+  test "update as JSON" do
+    put account_entropy_path, params: { entropy: { auto_postpone_period: 2.days } }, as: :json
+
+    assert_response :no_content
+    assert_equal 2.days, entropies("37s_account").reload.auto_postpone_period
+  end
+
   test "update requires admin" do
     logout_and_sign_in_as :david
 
diff --git a/test/controllers/accounts/exports_controller_test.rb b/test/controllers/accounts/exports_controller_test.rb
index ebcf26117..fd950f989 100644
--- a/test/controllers/accounts/exports_controller_test.rb
+++ b/test/controllers/accounts/exports_controller_test.rb
@@ -76,6 +76,49 @@ class Account::ExportsControllerTest < ActionDispatch::IntegrationTest
     assert_select "h2", "Download Expired"
   end
 
+  test "create as JSON" do
+    assert_difference -> { Account::Export.count }, 1 do
+      assert_enqueued_with(job: DataExportJob) do
+        post account_exports_path, as: :json
+      end
+    end
+
+    assert_response :created
+    body = @response.parsed_body
+    assert body["id"].present?
+    assert_equal "pending", body["status"]
+    assert_nil body["download_url"]
+  end
+
+  test "show as JSON with completed export" do
+    export = Account::Export.create!(account: Current.account, user: users(:jason))
+    export.build
+
+    get account_export_path(export), as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert_equal export.id, body["id"]
+    assert_equal "completed", body["status"]
+    assert body["download_url"].present?
+  end
+
+  test "show as JSON with pending export" do
+    export = Account::Export.create!(account: Current.account, user: users(:jason))
+
+    get account_export_path(export), as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert_equal "pending", body["status"]
+    assert_nil body["download_url"]
+  end
+
+  test "show as JSON with missing export" do
+    get account_export_path("nonexistent"), as: :json
+    assert_response :not_found
+  end
+
   test "create is forbidden for non-admin members" do
     logout_and_sign_in_as :david
 
diff --git a/test/controllers/accounts/join_codes_controller_test.rb b/test/controllers/accounts/join_codes_controller_test.rb
index 15d41b5ec..a56472c5c 100644
--- a/test/controllers/accounts/join_codes_controller_test.rb
+++ b/test/controllers/accounts/join_codes_controller_test.rb
@@ -24,6 +24,41 @@ class Account::JoinCodesControllerTest < ActionDispatch::IntegrationTest
     assert_redirected_to account_join_code_path
   end
 
+  test "show as JSON" do
+    get account_join_code_path, as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert body["code"].present?
+    assert body.key?("usage_count")
+    assert body.key?("usage_limit")
+    assert body.key?("url")
+    assert body.key?("active")
+  end
+
+  test "update as JSON" do
+    put account_join_code_path, params: { account_join_code: { usage_limit: 5 } }, as: :json
+
+    assert_response :no_content
+    assert_equal 5, Current.account.join_code.reload.usage_limit
+  end
+
+  test "update as JSON with invalid data" do
+    huge_number = "99999999999999999999999999999999999"
+
+    put account_join_code_path, params: { account_join_code: { usage_limit: huge_number } }, as: :json
+
+    assert_response :unprocessable_entity
+  end
+
+  test "destroy as JSON" do
+    assert_changes -> { Current.account.join_code.reload.code } do
+      delete account_join_code_path, as: :json
+    end
+
+    assert_response :no_content
+  end
+
   test "update requires admin" do
     logout_and_sign_in_as :david
 
diff --git a/test/controllers/accounts/settings_controller_test.rb b/test/controllers/accounts/settings_controller_test.rb
index 9f17a74a7..6f3fba5b0 100644
--- a/test/controllers/accounts/settings_controller_test.rb
+++ b/test/controllers/accounts/settings_controller_test.rb
@@ -16,6 +16,20 @@ class Account::SettingsControllerTest < ActionDispatch::IntegrationTest
     assert_redirected_to account_settings_path
   end
 
+  test "show as JSON" do
+    get account_settings_path, as: :json
+    assert_response :success
+
+    assert_equal Current.account.name, @response.parsed_body["name"]
+  end
+
+  test "update as JSON" do
+    put account_settings_path, params: { account: { name: "New Account Name" } }, as: :json
+
+    assert_response :no_content
+    assert_equal "New Account Name", Current.account.reload.name
+  end
+
   test "update requires admin" do
     logout_and_sign_in_as :david
 
diff --git a/test/controllers/api/flat_json_params_test.rb b/test/controllers/api/flat_json_params_test.rb
new file mode 100644
index 000000000..4efba5209
--- /dev/null
+++ b/test/controllers/api/flat_json_params_test.rb
@@ -0,0 +1,71 @@
+require "test_helper"
+
+class FlatJsonParamsTest < ActionDispatch::IntegrationTest
+  setup do
+    sign_in_as :kevin
+  end
+
+  test "update user role with flat JSON" do
+    put user_role_path(users(:david)), params: { role: "admin" }, as: :json
+
+    assert_response :no_content
+    assert users(:david).reload.admin?
+  end
+
+  test "update notification settings with flat JSON" do
+    logout_and_sign_in_as :david
+
+    assert_changes -> { users(:david).reload.settings.bundle_email_frequency }, from: "never", to: "every_few_hours" do
+      put notifications_settings_path, params: { bundle_email_frequency: "every_few_hours" }, as: :json
+    end
+
+    assert_response :no_content
+  end
+
+  test "update join code with flat JSON" do
+    put account_join_code_path, params: { usage_limit: 5 }, as: :json
+
+    assert_response :no_content
+    assert_equal 5, Current.account.join_code.reload.usage_limit
+  end
+
+  test "update account settings with flat JSON" do
+    put account_settings_path, params: { name: "New Name" }, as: :json
+
+    assert_response :no_content
+    assert_equal "New Name", Current.account.reload.name
+  end
+
+  test "update board entropy with flat JSON" do
+    board = boards(:writebook)
+
+    put board_entropy_path(board), params: { auto_postpone_period: 99.days }, as: :json
+
+    assert_response :no_content
+    assert_equal 99.days, board.entropy.reload.auto_postpone_period
+  end
+
+  test "update account entropy with flat JSON" do
+    put account_entropy_path, params: { auto_postpone_period: 2.days }, as: :json
+
+    assert_response :no_content
+    assert_equal 2.days, Current.account.entropy.reload.auto_postpone_period
+  end
+
+  test "create push subscription with flat JSON" do
+    stub_dns_resolution("142.250.185.206")
+
+    post user_push_subscriptions_path(users(:kevin)),
+      params: { endpoint: "https://fcm.googleapis.com/fcm/send/abc123", p256dh_key: "key1", auth_key: "key2" },
+      as: :json
+
+    assert_response :created
+  end
+
+  private
+    def stub_dns_resolution(*ips)
+      dns_mock = mock("dns")
+      dns_mock.stubs(:each_address).multiple_yields(*ips)
+      Resolv::DNS.stubs(:open).yields(dns_mock)
+    end
+end
diff --git a/test/controllers/boards/columns/closeds_controller_test.rb b/test/controllers/boards/columns/closeds_controller_test.rb
index f147a2106..90b6c8756 100644
--- a/test/controllers/boards/columns/closeds_controller_test.rb
+++ b/test/controllers/boards/columns/closeds_controller_test.rb
@@ -9,4 +9,11 @@ class Boards::Columns::ClosedsControllerTest < ActionDispatch::IntegrationTest
     get board_columns_closed_path(boards(:writebook))
     assert_response :success
   end
+
+  test "show as JSON" do
+    get board_columns_closed_path(boards(:writebook)), as: :json
+    assert_response :success
+
+    assert_kind_of Array, @response.parsed_body
+  end
 end
diff --git a/test/controllers/boards/columns/not_nows_controller_test.rb b/test/controllers/boards/columns/not_nows_controller_test.rb
index 29088728c..6f9efbf3e 100644
--- a/test/controllers/boards/columns/not_nows_controller_test.rb
+++ b/test/controllers/boards/columns/not_nows_controller_test.rb
@@ -9,4 +9,11 @@ class Boards::Columns::NotNowsControllerTest < ActionDispatch::IntegrationTest
     get board_columns_not_now_path(boards(:writebook))
     assert_response :success
   end
+
+  test "show as JSON" do
+    get board_columns_not_now_path(boards(:writebook)), as: :json
+    assert_response :success
+
+    assert_kind_of Array, @response.parsed_body
+  end
 end
diff --git a/test/controllers/boards/columns/streams_controller_test.rb b/test/controllers/boards/columns/streams_controller_test.rb
index fec9603cc..0fbc13afd 100644
--- a/test/controllers/boards/columns/streams_controller_test.rb
+++ b/test/controllers/boards/columns/streams_controller_test.rb
@@ -9,4 +9,12 @@ class Boards::Columns::StreamsControllerTest < ActionDispatch::IntegrationTest
     get board_columns_stream_path(boards(:writebook))
     assert_response :success
   end
+
+  test "show as JSON" do
+    get board_columns_stream_path(boards(:writebook)), as: :json
+    assert_response :success
+
+    assert_kind_of Array, @response.parsed_body
+    assert response.headers["X-Total-Count"].present?, "Expected X-Total-Count header"
+  end
 end
diff --git a/test/controllers/boards/columns_controller_test.rb b/test/controllers/boards/columns_controller_test.rb
index b9c974321..9fef675f5 100644
--- a/test/controllers/boards/columns_controller_test.rb
+++ b/test/controllers/boards/columns_controller_test.rb
@@ -75,6 +75,7 @@ class Boards::ColumnsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :created
     assert_equal board_column_path(board, Column.last, format: :json), @response.headers["Location"]
+    assert_equal "New Column", @response.parsed_body["name"]
   end
 
   test "update as JSON" do
diff --git a/test/controllers/boards/entropies_controller_test.rb b/test/controllers/boards/entropies_controller_test.rb
index 0c989c3cd..c0ec089a5 100644
--- a/test/controllers/boards/entropies_controller_test.rb
+++ b/test/controllers/boards/entropies_controller_test.rb
@@ -16,6 +16,13 @@ class Boards::EntropiesControllerTest < ActionDispatch::IntegrationTest
     end
   end
 
+  test "update as JSON" do
+    put board_entropy_path(@board), params: { board: { auto_postpone_period: 99.days } }, as: :json
+
+    assert_response :no_content
+    assert_equal 99.days, @board.entropy.reload.auto_postpone_period
+  end
+
   test "update requires board admin permission" do
     logout_and_sign_in_as :jz
 
diff --git a/test/controllers/boards/involvements_controller_test.rb b/test/controllers/boards/involvements_controller_test.rb
index 45587176a..4045df743 100644
--- a/test/controllers/boards/involvements_controller_test.rb
+++ b/test/controllers/boards/involvements_controller_test.rb
@@ -15,4 +15,15 @@ class Boards::InvolvementsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :success
   end
+
+  test "update as JSON" do
+    board = boards(:writebook)
+    board.access_for(users(:kevin)).access_only!
+
+    assert_changes -> { board.access_for(users(:kevin)).involvement }, from: "access_only", to: "watching" do
+      put board_involvement_path(board), params: { involvement: "watching" }, as: :json
+    end
+
+    assert_response :no_content
+  end
 end
diff --git a/test/controllers/boards_controller_test.rb b/test/controllers/boards_controller_test.rb
index 7dd2b2f06..fedd9d188 100644
--- a/test/controllers/boards_controller_test.rb
+++ b/test/controllers/boards_controller_test.rb
@@ -275,6 +275,7 @@ class BoardsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :created
     assert_equal board_path(Board.last, format: :json), @response.headers["Location"]
+    assert_equal "My new board", @response.parsed_body["name"]
   end
 
   test "update as JSON" do
diff --git a/test/controllers/cards/comments/reactions_controller_test.rb b/test/controllers/cards/comments/reactions_controller_test.rb
index 21a94c5f3..eda47536f 100644
--- a/test/controllers/cards/comments/reactions_controller_test.rb
+++ b/test/controllers/cards/comments/reactions_controller_test.rb
@@ -49,6 +49,7 @@ class Cards::Comments::ReactionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :created
+    assert_equal "👍", @response.parsed_body["content"]
   end
 
   test "destroy as JSON" do
diff --git a/test/controllers/cards/comments_controller_test.rb b/test/controllers/cards/comments_controller_test.rb
index a6e83cbef..eebd62a9c 100644
--- a/test/controllers/cards/comments_controller_test.rb
+++ b/test/controllers/cards/comments_controller_test.rb
@@ -56,6 +56,7 @@ class Cards::CommentsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :created
     assert_equal card_comment_path(card, Comment.last, format: :json), @response.headers["Location"]
+    assert_equal Comment.last.id, @response.parsed_body["id"]
   end
 
   test "create as JSON with custom created_at" do
diff --git a/test/controllers/cards/publishes_controller_test.rb b/test/controllers/cards/publishes_controller_test.rb
index 537a6f73b..1a6325e2f 100644
--- a/test/controllers/cards/publishes_controller_test.rb
+++ b/test/controllers/cards/publishes_controller_test.rb
@@ -16,6 +16,17 @@ class Cards::PublishesControllerTest < ActionDispatch::IntegrationTest
     assert_redirected_to card.board
   end
 
+  test "create as JSON" do
+    card = cards(:logo)
+    card.drafted!
+
+    assert_changes -> { card.reload.published? }, from: false, to: true do
+      post card_publish_path(card), as: :json
+    end
+
+    assert_response :created
+  end
+
   test "create and add another" do
     card = cards(:logo)
     card.drafted!
diff --git a/test/controllers/cards/reactions_controller_test.rb b/test/controllers/cards/reactions_controller_test.rb
index 86ab22639..731d606d8 100644
--- a/test/controllers/cards/reactions_controller_test.rb
+++ b/test/controllers/cards/reactions_controller_test.rb
@@ -53,6 +53,7 @@ class Cards::ReactionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :created
+    assert_equal "👍", @response.parsed_body["content"]
   end
 
   test "destroy as JSON" do
diff --git a/test/controllers/cards/readings_controller_test.rb b/test/controllers/cards/readings_controller_test.rb
index 0c9c9aeed..4aaec41d7 100644
--- a/test/controllers/cards/readings_controller_test.rb
+++ b/test/controllers/cards/readings_controller_test.rb
@@ -39,6 +39,18 @@ class Cards::ReadingsControllerTest < ActionDispatch::IntegrationTest
     assert_response :success
   end
 
+  test "create as JSON" do
+    post card_reading_url(cards(:logo)), as: :json
+    assert_response :created
+  end
+
+  test "destroy as JSON" do
+    notifications(:logo_assignment_kevin).read
+
+    delete card_reading_url(cards(:logo)), as: :json
+    assert_response :no_content
+  end
+
   test "unread notification on destroy" do
     notifications(:logo_assignment_kevin).read
 
diff --git a/test/controllers/cards/steps_controller_test.rb b/test/controllers/cards/steps_controller_test.rb
index 039fbf4c4..011b68812 100644
--- a/test/controllers/cards/steps_controller_test.rb
+++ b/test/controllers/cards/steps_controller_test.rb
@@ -53,6 +53,19 @@ class Cards::StepsControllerTest < ActionDispatch::IntegrationTest
     end
   end
 
+  test "index as JSON" do
+    card = cards(:logo)
+    card.steps.create!(content: "Step one")
+    card.steps.create!(content: "Step two", completed: true)
+
+    get card_steps_path(card), as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert_equal 2, body.size
+    assert_equal "Step one", body.first["content"]
+  end
+
   test "create as JSON" do
     card = cards(:logo)
 
@@ -62,6 +75,7 @@ class Cards::StepsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :created
     assert_equal card_step_path(card, Step.last, format: :json), @response.headers["Location"]
+    assert_equal "New step", @response.parsed_body["content"]
   end
 
   test "show as JSON" do
diff --git a/test/controllers/cards_controller_test.rb b/test/controllers/cards_controller_test.rb
index 42e24d927..901a584f9 100644
--- a/test/controllers/cards_controller_test.rb
+++ b/test/controllers/cards_controller_test.rb
@@ -192,6 +192,7 @@ class CardsControllerTest < ActionDispatch::IntegrationTest
 
     card = Card.last
     assert_equal card_path(card, format: :json), @response.headers["Location"]
+    assert_equal "My new card", @response.parsed_body["title"]
 
     assert_equal "My new card", card.title
     assert_equal "Big if true", card.description.to_plain_text
diff --git a/test/controllers/columns/left_positions_controller_test.rb b/test/controllers/columns/left_positions_controller_test.rb
index 6c807b0e5..5f1c0cd26 100644
--- a/test/controllers/columns/left_positions_controller_test.rb
+++ b/test/controllers/columns/left_positions_controller_test.rb
@@ -21,6 +21,22 @@ class Columns::LeftPositionsControllerTest < ActionDispatch::IntegrationTest
     assert_equal original_position_a, column_b.reload.position
   end
 
+  test "move column left as JSON" do
+    board = boards(:writebook)
+    columns = board.columns.sorted.to_a
+
+    column_a = columns[0]
+    column_b = columns[1]
+    original_position_a = column_a.position
+    original_position_b = column_b.position
+
+    post column_left_position_path(column_b), as: :json
+    assert_response :created
+
+    assert_equal original_position_b, column_a.reload.position
+    assert_equal original_position_a, column_b.reload.position
+  end
+
   test "move left refreshes adjacent columns" do
     column = columns(:writebook_in_progress)
 
diff --git a/test/controllers/columns/right_positions_controller_test.rb b/test/controllers/columns/right_positions_controller_test.rb
index c927531be..1ee7a0987 100644
--- a/test/controllers/columns/right_positions_controller_test.rb
+++ b/test/controllers/columns/right_positions_controller_test.rb
@@ -21,6 +21,22 @@ class Columns::RightPositionsControllerTest < ActionDispatch::IntegrationTest
     assert_equal original_position_a, column_b.reload.position
   end
 
+  test "move column right as JSON" do
+    board = boards(:writebook)
+    columns = board.columns.sorted.to_a
+
+    column_a = columns[0]
+    column_b = columns[1]
+    original_position_a = column_a.position
+    original_position_b = column_b.position
+
+    post column_right_position_path(column_a), as: :json
+    assert_response :created
+
+    assert_equal original_position_b, column_a.reload.position
+    assert_equal original_position_a, column_b.reload.position
+  end
+
   test "move right refreshes adjacent columns" do
     column = columns(:writebook_in_progress)
 
diff --git a/test/controllers/my/access_tokens_controller_test.rb b/test/controllers/my/access_tokens_controller_test.rb
index 176302336..bced907db 100644
--- a/test/controllers/my/access_tokens_controller_test.rb
+++ b/test/controllers/my/access_tokens_controller_test.rb
@@ -25,9 +25,11 @@ class My::AccessTokensControllerTest < ActionDispatch::IntegrationTest
     end
     assert_response :created
     body = @response.parsed_body
+    assert body["id"].present?
     assert body["token"].present?
     assert_equal "Fizzy CLI", body["description"]
     assert_equal "write", body["permission"]
+    assert body["created_at"].present?
   end
 
   test "create new token via JSON with bearer token" do
@@ -54,6 +56,36 @@ class My::AccessTokensControllerTest < ActionDispatch::IntegrationTest
     assert_response :unauthorized
   end
 
+  test "index as JSON" do
+    get my_access_tokens_path, as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert_kind_of Array, body
+  end
+
+  test "index as JSON with bearer token and no account scope" do
+    sign_out
+    bearer_token = { "HTTP_AUTHORIZATION" => "Bearer #{identity_access_tokens(:davids_api_token).token}" }
+
+    untenanted do
+      get my_access_tokens_path, as: :json, env: bearer_token
+    end
+
+    assert_response :success
+    assert_kind_of Array, @response.parsed_body
+  end
+
+  test "destroy as JSON" do
+    token = identities(:kevin).access_tokens.create!(description: "To delete", permission: "read")
+
+    assert_difference -> { identities(:kevin).access_tokens.count }, -1 do
+      delete my_access_token_path(token), as: :json
+    end
+
+    assert_response :no_content
+  end
+
   test "accessing new token after reveal window redirects to index" do
     assert_changes -> { identities(:kevin).access_tokens.count }, +1 do
       post my_access_tokens_path, params: { access_token: { description: "GitHub", permission: "read" } }
diff --git a/test/controllers/notifications/settings_controller_test.rb b/test/controllers/notifications/settings_controller_test.rb
index d8472bb02..b5b554c34 100644
--- a/test/controllers/notifications/settings_controller_test.rb
+++ b/test/controllers/notifications/settings_controller_test.rb
@@ -13,6 +13,21 @@ class Notifications::SettingsControllerTest < ActionDispatch::IntegrationTest
     assert_response :success
   end
 
+  test "show as JSON" do
+    get notifications_settings_path, as: :json
+    assert_response :success
+
+    assert_equal @user.settings.bundle_email_frequency, @response.parsed_body["bundle_email_frequency"]
+  end
+
+  test "update as JSON" do
+    assert_changes -> { @user.reload.settings.bundle_email_frequency }, from: "never", to: "every_few_hours" do
+      put notifications_settings_path, params: { user_settings: { bundle_email_frequency: "every_few_hours" } }, as: :json
+    end
+
+    assert_response :no_content
+  end
+
   test "update email frequency" do
     assert_changes -> { @user.reload.settings.bundle_email_frequency }, from: "never", to: "every_few_hours" do
       put notifications_settings_path, params: { user_settings: { bundle_email_frequency: "every_few_hours" } }
diff --git a/test/controllers/searches_controller_test.rb b/test/controllers/searches_controller_test.rb
index 11bac3bc9..b0172cdf5 100644
--- a/test/controllers/searches_controller_test.rb
+++ b/test/controllers/searches_controller_test.rb
@@ -46,6 +46,36 @@ class SearchesControllerTest < ActionDispatch::IntegrationTest
     assert_select ".search__blank-slate", text: "No matches"
   end
 
+  test "search as JSON" do
+    get search_path(q: "broken", script_name: "/#{@account.external_account_id}"), as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert_kind_of Array, body
+    assert_equal 1, body.size
+    assert_equal "Layout is broken", body.first["title"]
+  end
+
+  test "search by card ID as JSON returns array" do
+    get search_path(q: @card.id, script_name: "/#{@account.external_account_id}"), as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert_kind_of Array, body
+    assert_equal 1, body.size
+    assert_equal @card.id, body.first["id"]
+  end
+
+  test "search as JSON deduplicates cards with multiple search hits" do
+    get search_path(q: "haggis", script_name: "/#{@account.external_account_id}"), as: :json
+    assert_response :success
+
+    body = @response.parsed_body
+    assert_kind_of Array, body
+    assert_equal 1, body.size
+    assert_equal @comment2_card.id, body.first["id"]
+  end
+
   test "search highlights matched terms with proper HTML marks" do
     @board.cards.create!(title: "Testing search highlighting", status: "published", creator: @user)
 
diff --git a/test/controllers/users/avatars_controller_test.rb b/test/controllers/users/avatars_controller_test.rb
index 3ded884b8..ac213e46b 100644
--- a/test/controllers/users/avatars_controller_test.rb
+++ b/test/controllers/users/avatars_controller_test.rb
@@ -49,6 +49,11 @@ class Users::AvatarsControllerTest < ActionDispatch::IntegrationTest
     assert_redirected_to users(:david)
   end
 
+  test "delete self as JSON" do
+    delete user_avatar_path(users(:david)), as: :json
+    assert_response :no_content
+  end
+
   test "unable to delete other" do
     delete user_avatar_path(users(:kevin))
     assert_response :forbidden
diff --git a/test/controllers/users/push_subscriptions_controller_test.rb b/test/controllers/users/push_subscriptions_controller_test.rb
index 4b4dd0a09..b9f43ff0a 100644
--- a/test/controllers/users/push_subscriptions_controller_test.rb
+++ b/test/controllers/users/push_subscriptions_controller_test.rb
@@ -20,6 +20,42 @@ class Users::PushSubscriptionsControllerTest < ActionDispatch::IntegrationTest
     assert_equal "Mozilla/5.0", users(:david).push_subscriptions.last.user_agent
   end
 
+  test "create as JSON" do
+    subscription_params = { "endpoint" => "https://fcm.googleapis.com/fcm/send/abc123", "p256dh_key" => "123", "auth_key" => "456" }
+
+    post user_push_subscriptions_path(users(:david)),
+      params: { push_subscription: subscription_params }, headers: { "HTTP_USER_AGENT" => "Mozilla/5.0" }, as: :json
+
+    assert_response :created
+  end
+
+  test "create as JSON for duplicate subscription" do
+    subscription_params = { "endpoint" => "https://fcm.googleapis.com/fcm/send/abc123", "p256dh_key" => "123", "auth_key" => "456" }
+
+    users(:david).push_subscriptions.create!(subscription_params)
+
+    assert_no_difference -> { Push::Subscription.count } do
+      post user_push_subscriptions_path(users(:david)),
+        params: { push_subscription: subscription_params }, as: :json
+    end
+
+    assert_response :created
+  end
+
+  test "destroy as JSON" do
+    subscription = users(:david).push_subscriptions.create!(
+      endpoint: "https://fcm.googleapis.com/fcm/send/abc123",
+      p256dh_key: "123",
+      auth_key: "456"
+    )
+
+    assert_difference -> { Push::Subscription.count }, -1 do
+      delete user_push_subscription_path(users(:david), subscription), as: :json
+    end
+
+    assert_response :no_content
+  end
+
   test "destroy a push subscription" do
     subscription = users(:david).push_subscriptions.create!(
       endpoint: "https://fcm.googleapis.com/fcm/send/abc123",
diff --git a/test/controllers/users/roles_controller_test.rb b/test/controllers/users/roles_controller_test.rb
index 37d1f2067..d0091bc53 100644
--- a/test/controllers/users/roles_controller_test.rb
+++ b/test/controllers/users/roles_controller_test.rb
@@ -14,6 +14,13 @@ class Users::RolesControllerTest < ActionDispatch::IntegrationTest
     assert users(:david).reload.admin?
   end
 
+  test "update as JSON" do
+    put user_role_path(users(:david)), params: { user: { role: "admin" } }, as: :json
+
+    assert_response :no_content
+    assert users(:david).reload.admin?
+  end
+
   test "can't promote to special roles" do
     assert_no_changes -> { users(:david).reload.role } do
       put user_role_path(users(:david)), params: { user: { role: "system" } }