Notice: axlsx_rails renamed to caxlsx_rails

This gem has been renamed to match other gems in the Axlsx community organization:

Axlsx-Rails — Spreadsheet templates for Rails

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Notice: Community Axlsx Organization

To better maintain the Axlsx ecosystem, all related gems have been forked or moved to the following community organization:

Join the Caxlsx Slack channel


In your Gemfile:

gem 'caxlsx'
gem 'caxlsx_rails'

See previous installations if needed.


  • Tested on Rails 4.2, 5.x and 6.0
  • For Rails 3.1 or 3.2 use version 3.0
  • As of 0.5.0 requires Axlsx 2.0.1, but strongly suggests 2.1.0.pre, which requires rubyzip 1.1.0
  • As of Rails 4.1 you must use render_to_string to render a mail attachment.



Axlsx-Rails provides a renderer and a template handler. It adds the :xlsx format and parses .xlsx.axlsx templates. This lets you take all the caxlsx code out of your controller or model and place it inside the template, where view code belongs! See this blog post for a more complete walkthrough.


To use Axlsx-Rails set your instance variables in your controller and configure the response if needed:

class ButtonController < ApplicationController
  def action_name
    @buttons = Button.all
    respond_to do |format|


Create the template with the .xlsx.axlsx extension (action_name.xlsx.axlsx for example.) Watch out for typos! In the template, use xlsx_package variable to create your spreadsheet:

wb = xlsx_package.workbook
wb.add_worksheet(name: "Buttons") do |sheet|
  @buttons.each do |button|
    sheet.add_row [, button.category, button.price]

This is where you place all your caxlsx specific markup. Add worksheets, fill content, merge cells, add styles. See the caxlsx examples page to see what you can do.

Remember, like in erb templates, view helpers are available to use the .xlsx.axlsx template.

That's it. Call your action and your spreadsheet will be delivered.

Rendering Options

You can call render in any of the following ways:

# rendered, no disposition/filename header
render 'buttons'
# rendered from another controller, no disposition/filename header
render 'featured/latest'
# template and filename of 'buttons'
render xlsx: 'buttons'
# template from another controller, filename of 'latest_buttons'
render xlsx: 'latest_buttons', template: 'featured/latest'


To specify a disposition (such as inline so the spreadsheet is opened inside the browser), use the disposition option:

render xlsx: "buttons", disposition: 'inline'

If render xlsx: is called, the disposition defaults to attachment.

File name

If Rails calls Axlsx through default channels (because you use format.xlsx {} for example) you must set the filename using the response header:

format.xlsx {
  response.headers['Content-Disposition'] = 'attachment; filename="my_new_filename.xlsx"'

If you use render xlsx: the gem will try to guess the file name:

# filename of 'buttons'
render xlsx: 'buttons'
# filename of 'latest_buttons'
render xlsx: 'latest_buttons', template: 'featured/latest'

If that fails, pass the :filename parameter:

render xlsx: "action_or_template", filename: "my_new_filename.xlsx"

Acts As Xlsx

If you use acts_as_xlsx, configure the active record normally, but specify the package in the template:

User.to_xlsx package: xlsx_package, (other options)

Note: As of 4/1/2014 Acts As Xlsx is not compatible with Rails 4.1, and generates a warning on 4.0. You may use my patched fork until it is remedied.

Axlsx Package Options

Axlsx provides three options for initializing a spreadsheet:

  • :xlsx_author (String) - The author of the document
  • :xlsx_created_at (Time) - Timestamp in the document properties (defaults to current time)
  • :xlsx_use_shared_strings (Boolean) - This is passed to the workbook to specify that shared strings should be used when serializing the package.

To pass these to the new package, pass them to render :xlsx or pass them as local variables.

For example, to set the author name, pass the :xlsx_author parameter to render :xlsx or as a local variable:

render xlsx: "index", xlsx_author: "Elmer Fudd"
render "index", locals: {xlsx_author: "Elmer Fudd"}

Other examples:

render xlsx: "index", xlsx_created_at: 3.days.ago
render "index", locals: {xlsx_use_shared_strings: true}


Partials work as expected, but you must pass in relevant spreadsheet variables:

wb = xlsx_package.workbook
render :partial => 'cover_sheet', :locals => {:wb => wb}
wb.add_worksheet(name: "Content") do |sheet|
  sheet.add_row ['Content']

With the partial simply using the passed variables:

wb.add_worksheet(name: "Cover Sheet") do |sheet|
  sheet.add_row ['Cover', 'Sheet']


To use an xlsx template to render a mail attachment, use the following syntax:

class UserMailer < ActionMailer::Base
  def export(users)
    xlsx = render_to_string layout: false, handlers: [:axlsx], formats: [:xlsx], template: "users/export", locals: {users: users}
    attachment = Base64.encode64(xlsx)
    attachments["Users.xlsx"] = {mime_type: Mime[:xlsx], content: attachment, encoding: 'base64'}
    # For rails 4 use Mime::XLSX
    # attachments["Users.xlsx"] = {mime_type: Mime::XLSX, content: attachment, encoding: 'base64'}
    # self.instance_variable_set(:@_lookup_context, nil) # If attachments are rendered as content, try this and open an issue
  • If the route specifies or suggests the :xlsx format you do not need to specify formats or handlers.
  • If the template (users/export) can refer to only one file (the xlsx.axlsx template), you do not need to specify handlers, provided the formats includes :xlsx.
  • Specifying the encoding as 'base64' can avoid UTF-8 errors.


To generate a template within a script, you need to instantiate an ActionView context. Here are two gists showing how to perform this:


There is no built-in way to test your resulting workbooks / templates. But here is a piece of code that may help you to find a way.

First, create a shared context

RSpec.shared_context 'axlsx' do

  # all xlsx specs describe must be normalized
  # "folder/view_name.xlsx.axlsx"
  # allow to infer the template path
  template_name = description

  let(:template_path) do
    ['app', 'views', template_name]

  # This helper will be used in tests
  def render_template(locals = {})
    axlsx_binding = Kernel.binding
    locals.each do |key, value|
      axlsx_binding.local_variable_set key, value
    # define a default workbook and a default sheet useful when testing partial in isolation
    wb =
    axlsx_binding.local_variable_set(:wb, wb)
    axlsx_binding.local_variable_set(:sheet, wb.add_worksheet)

    # mimics an ActionView::Template class, presenting a 'source' method
    # to retrieve the content of the template
    filename = Rails.root.join(*template_path).to_s
    source =
    axlsx_binding.eval(, filename)

Include it in your spec files:

require 'spec_helper'
require 'helpers/axlsx_context'

describe 'shared/_total_request.xlsx.axlsx' do
  include_context 'axlsx'

  before :each do
    # all the instance variables here are the one used in 'shared/_total_request.xlsx.axlsx'
    @widget = mock_model(Widget, name: 'My widget')
    @message_counts =, :positives, :negatives, :neutrals).new(42, 23, 15, 25)

  it 'has a title line mentioning the widget' do
    wb = render_template
    sheet = wb.sheet_by_name('Réf. Requête')
    expect(sheet).to have_header_cells ['My widget : Messages de la requête']

  it 'exports the message counts' do
    wb = render_template
    sheet = wb.sheet_by_name('Réf. Requête')
    expect(sheet).to have_cells(['Toutes tonalités', 'Tonalité positive', 'Tonalité négative', 'Tonalité neutre']).in_row(2)
    expect(sheet).to have_cells([42, 23, 15, 25]).in_row(3)


Matchers used

# encoding: UTF-8

require 'rspec/expectations'

module XlsxMatchers

  RSpec::Matchers.define :have_header_cells do |cell_values|
    match do |worksheet|
      worksheet.rows[0] == cell_values

    failure_message do |actual|
      "Expected #{actual.rows[0]} to be #{expected}"

  RSpec::Matchers.define :have_cells do |expected|
    match do |worksheet|
      worksheet.rows[@index] == expected

    chain :in_row do |index|
      @index = index

    failure_message do |actual|
      "Expected #{actual.rows[@index]} to include #{expected} at row #{@index}."



It is easy to get the spelling wrong in the extension name, the format.xlsx statement, or in a render call. Here are some possibilities:

  • If it says your template is missing, check that its extension is .xlsx.axlsx.
  • If you get the error uninitialized constant Mime::XSLX you have used format.xslx instead of format.xlsx, or something similar.

Using axlsx_rails in API mode

In API mode Rails does not include ActionView, so axlsx_rails will not work. To render axlsx_rails templates you must include ActionView::Rendering in your controller and override render_to_body:

class MyController < ActionController::API
  include ActionView::Rendering

  def show
    respond_to do |format|


  def render_to_body(options)
    _render_to_body_with_renderer(options) || super

See issue 107

Mailer Attachments: No content, cannot read, Invalid Byte Sequence in UTF-8

If you are having problems with rendering a template and attaching it to a template, try a few options:

  • Make sure the attachment template does not have the same name as the mailer.
  • After you have rendered the template to string, and before you call the mailer, execute self.instance_variable_set(:@_lookup_context, nil). If you must do this, please open an issue.
  • If you get Invalid Byte Sequence in UTF-8, pass encoding: 'base64' with the attachment:
class UserMailer < ActionMailer::Base
  def export(users)
    xlsx = render_to_string handlers: [:axlsx], formats: [:xlsx], template: "users/export", locals: {users: users}
    attachments["Users.xlsx"] = {mime_type: Mime[:xlsx], content: xlsx, encoding: 'base64'}
    # For Rails 4 use Mime::XLSX
    # attachments["Users.xlsx"] = {mime_type: Mime::XLSX, content: xlsx, encoding: 'base64'}
    # self.instance_variable_set(:@_lookup_context, nil) # If attachments are rendered as content, try this and open an issue

If you get these errors, please open an issue and share code so the bug can be isolated. Or comment on issue #29 or #25.

The unparsed template is returned, or something similar

Have you followed other tutorials for serving Excel from Rails? Have you declared the MIME type already? These may be incompatible with caxlsx_rails (which declares the MIME type for you.) Remove any vestiges of other tutorials from your code and try again.

Generated Files Can't Be Opened or Invalid Byte Sequence in UTF-8

Both these errors appear to be caused by Rails applying a layout to the template. Passing layout: false to render :xlsx should fix this issue. Version 0.5.0 attempts to fix this issue.

If you get this error, please open an issue and share code so the bug can be isolated.

Rails 4.2 changes

Before Rails 4.2 you could call:

  render xlsx: "users/index"

And caxlsx_rails could adjust the paths and make sure the template was loaded from the right directory. This is no longer possible because the paths are cached between requests for a given controller. As a result, to display a template in another directory you must use the :template parameter (which is normal Rails behavior anyway):

  render xlsx: "index", template: "users/index"

If the request format matches you should be able to call:

  render "users/index"

This is a breaking change if you have the old syntax!

If you are using turbolinks, you may need to disable turbolinks when you link to your spreadsheet:

# turbolinks 5:
link_to 'Download spreadsheet', path_to_sheet, data: {turbolinks: false}

Rails 7 Unknown Format

In Rails 7, if you get an error of "Unknown Format" you may need to add (format: "xlsx") to the named route.

A clue to the "format" that Rails is responding with is to look at your log file or console after you click the HTML link or submit your form. You should see Processing by Controller#action as XLSX.

Code Examples

Scenario 1 - HTML Link within index.html.erb

link_to "Download as Excel", my_named_route_path(format: "xlsx")

Scenario 2 - Using form_with()

form_with method: :post, url: my_named_route_path(format: :xlsx) do |f|

What to do

If you are having problems, try to isolate the issue. Use the console or a script to make sure your data is good. Then create the spreadsheet line by line without Axlsx-Rails to see if you are having caxlsx problems. If you can manually create the spreadsheet, create an issue and we will work it out.

Previous Installations

In your Gemfile:

gem 'rubyzip', '>= 1.2.1'
gem 'axlsx', git: '', ref: 'c8ac844'
gem 'axlsx_rails'

If rubyzip 1.0.0 is needed:

gem 'rubyzip', '= 1.0.0'
gem 'axlsx', '= 2.0.1'
gem 'axlsx_rails'

If rubyzip >= 1.1.0 is needed:

gem 'rubyzip', '~> 1.1.0'
gem 'axlsx', '2.1.0.pre'
gem 'axlsx_rails'




Many thanks to contributors:

Change log

March 8, 2022: 0.6.3 release

December 18, 2019: 0.6.2 release

  • Release under caxlsx_rails

December 18, 2019: 0.6.1 release

  • Deprecate axlsx_rails name, release under caxlsx_rails
  • Switch to using caxlsx 3.0 gem

September 5, 2019: 0.6.0 release

  • Improved Rails 6.0 compatibility re MIME type

May 1st, 2018: 0.5.2 release

  • Improved Rails 5 compatibility re MIME type

March 29th, 2017: 0.5.1 release

July 26st, 2016: 0.5.0 release

  • Support for Rails 5
  • Tested on on Rails 4.0, 4.1, 4.2, and 5.0
  • Bug fixes for unreadable files and UTF-8 errors

July 13th, 2015: 0.4.0 release

  • Support for Rails 4.2
  • Removal of forced default_formats (url format must match)
  • Tested only on Rails 4.1 and 4.2
  • For Rails 3.2 or below, use 0.3.0

November 20th, 2014: 0.3.0 release

  • Support for Rails 4.2.beta4.
  • Removal of shorthand template syntax (render xlsx: 'another/directory')

September 4, 2014: 0.2.1 release

  • Rails 4.2.beta1 no longer includes responder. This release checks for the existence of responder before configuring a default responder.
  • Rails 4.2 testing, though not yet on Travis CI
  • Author, created_at, and use_shared_strings parameters for

April 9, 2014: 0.2.0 release

  • Require Axlsx 2.0.1, which requires rubyzip 1.0.0
  • Better render handling and testing, which might break former usage
  • Rails 4.1 testing
  • Mailer example update (use render_to_string not render)

October 11, 2013

  • Handle (and test) respond_to override

October 4, 2013

  • Added coveralls
  • Raised testing to axlsx 2.0.1, roo 1.12.2, and rubyzip 1.0.0

July 25, 2013

  • Documentation improved
  • Testing for generating partial in mailer

January 18, 2013: 0.1.4 release

  • Now supports Rails 4 (thanks Envek)
  • If you call render :xlsx on a request without :xlsx format, it should force the :xlsx format. Works on Rails 3.2+.

December 6, 2012: 0.1.3 release

  • Fix for absolute template paths

July 25, 2012: 0.1.2 release

  • Partials tested

July 19, 2012: 0.1.1 release

  • Travis-ci added (thanks randym)
  • render statements and filename tests fixes (thanks engwan)

July 17, 2012: 0.1.0 release

  • Tests completed
  • Acts_as_xlsx tested, example in docs

July 12, 2012: 0.0.1 release

  • Initial posting.
  • It works, but there are no tests! Bad programmer!