Cynapta Azure CORS Helper – Free Tool to Manage CORS Rules for Windows Azure Blob Storage

Recently Windows Azure Storage Team released a bunch of new changes to core storage service. One of that change is the support for Cross-Origin Resource Sharing (CORS). I wrote a few blog posts on my personal blog about these changes and CORS in particular which you can read here:

For the product we are currently building at Cynapta, CORS support was really crucial. In order to manage CORS rules, we ended up writing a small desktop utility – Cynapta Azure CORS Helper. I’m pleased to announce that we’re releasing this utility today for you to use for Free!  You can download the application binaries from here: To use it, simply unzip the files and run the executable.


Currently this utility only allows you to manage CORS rules for blob service only (currently that was the only thing important for us so we started with that). You could add/modify/delete CORS rules for blob service with this tool. We are also releasing the source code as well so that you can modify the code to suit your need. You can download the source code from here:

What You Need

This application makes use of .Net 4.5 so you would need that to run the application. Apart from that all you will need is credentials for the storage account for which you want to manage the CORS rules.

How to Use

When you launch the application, it will ask you to provide storage account name and key. After entering these, just click on “Get CORS Rules” button and it will fetch existing CORS rules and show them on the grid.

To add a CORS rule, click on the “Add” icon and it will open up a window where you can specify CORS rules.

To update a CORS rule, just double click on any of the CORS rule displayed in the grid. That particular rule’s setting will be displayed in the popup window. Just make appropriate changes and hit save to save the changes.

To delete a CORS rule, just click on the “Delete” icon for that CORS rule and that rule will be deleted.

For help, just click on the “Help” icon and it will redirect you to documentation by Storage team on MSDN page.

By default the application picks up the storage credentials from settings in app.config file. If you work with just one storage account, you can specify them in app.config file as well.

Closing Thoughts

Do give it a try and we hope you will find it useful. Since we are also releasing the source code, you should be able to make minor code modifications to suit your needs or to use the same for managing CORS rules for table service and queue service.


    • Gaurav Mantri says

      Sorry about that :(. While playing with CORS, we accidentally messed up something with that storage account because of which download links were not working. The issue has been fixed. Can you please try now? You should be able to download both executable and source code.


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