Programmable Media

Ruby/Rails SDK

Last updated: May-08-2024

This page provides an in-depth introduction to the Ruby/Rails SDK.

If you're ready to get coding, jump straight to the Ruby/Rails quick start.
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Cloudinary's Ruby/Rails SDK provides simple, yet comprehensive image and video upload, transformation, optimization, and delivery capabilities that you can implement using code that integrates seamlessly with your existing Ruby/Rails application.

Related topics
This guide relates to the latest released version of the cloudinary_gem library.

For details on all new features and fixes from previous versions, see the CHANGELOG.

Quick example: Transformations

Take a look at the following transformation code and the image it delivers:

sample transformation

This relatively simple code performs all of the following on the original front_face.jpg image before delivering it:

  • Crop to a 150x150 thumbnail using face-detection gravity to automatically determine the location for the crop
  • Round the corners with a 20 pixel radius
  • Apply a sepia effect
  • Overlay the Cloudinary logo on the southeast corner of the image (with a slight offset). The logo is scaled down to a 50 pixel width, with increased brightness and partial transparency (opacity = 60%)
  • Rotate the resulting image (including the overlay) by 10 degrees
  • Convert and deliver the image in PNG format (the originally uploaded image was a JPG)

And here's the URL that would be included in the image tag that's automatically generated from the above code:

In a similar way, you can transform a video.

Learn more about transformations

Quick example: File upload

The following Ruby code uploads the dog.mp4 video to the specified sub-folder using the public_id, my_dog. The video will overwrite the existing my_dog video if it exists. When the video upload is complete, the specified notification URL will receive details about the uploaded media asset.

Ruby gem features

Cloudinary provides a Ruby gem (open source) that simplifies the integration with your Ruby and Ruby on Rails applications:


Cloudinary's Ruby library is available as an open-source Ruby gem.

To install the Cloudinary Ruby gem, run:

If you use Rails, edit your Gemfile, add the following line and run bundle.


To use the Cloudinary Ruby/Rails library, you have to configure at least your cloud_name. Your api_key and api_secret are also needed for secure API calls to Cloudinary (e.g., image and video uploads). You can find your product environment configuration credentials in the Dashboard page of the Cloudinary Console.

In addition to the required configuration parameters, you can define a number of optional configuration parameters if relevant.

You can set your configuration parameters:

  • You can always override the values specified in cloudinary.yml or initializer file by passing different values in specific Cloudinary calls.
  • If you use more than one method of setting configuration options, the order of precedence is:
    CLOUDINARY_URL -> cloud_name -> cloudinary.yml/cloudinary.rb
  • For backward compatibility reasons, the default value of the optional secure configuration parameter is false. However, for most modern applications, it's recommended to configure the secure parameter to true to ensure that your transformation URLs are always generated as HTTPS.

Setting the CLOUDINARY_URL environment variable

You can configure the required cloud_name, api_key, and api_secret by defining the CLOUDINARY_URL environment variable. The CLOUDINARY_URL value is available in the Dashboard page of the Cloudinary Console. When using Cloudinary through a PaaS add-on (e.g., Heroku or AppFog), this environment variable is automatically defined in your deployment environment. For example:

Set additional parameters, for example upload_prefix and cname, to the environment variable:

cloudinary.yml method

Configure your Cloudinary credentials and any other optional configuration options (for example, secure:true) as follows:

If using Rails, place the above in a cloudinary.yml file under the config folder of your Rails project.

initializer method

Configure your Cloudinary credentials and any other optional configuration options (for example, secure:true) as follows:

Or alternatively

If using Rails, place the above in a file named cloudinary.rb in the /config/initializers folder of your Rails project.

Ruby capitalization and data type guidelines

When using the Ruby/Rails SDK, keep these guidelines in mind:

  • Parameter names: snake_case. For example: public_id
  • Classes: PascalCase. For example: PictureUploader
  • Methods: snake_case. For example: cl_image_upload_tag
  • Pass parameter data as: Hash

Sample projects

For additional useful code samples and to learn how to integrate Cloudinary with your Rails applications, take a look at our Sample Projects.

  • Basic Ruby sample: Uploading local and remote images to Cloudinary and generating various transformation URLs.
  • Basic Rails sample: Uploading local and remote images in a Rails project while embedding various transformed images in a Rails web view.
  • Rails Photo Album: A fully working web application. It uses CarrierWave to manage images of an album model (database). Performs image uploading both from the server side and directly from the browser using a jQuery plugin.

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