Looks great, awesome job.

I see there's ability to upload directly to S3, any ability to upload direct to Azure Blob store?

Sorry, no. If you really need it today, you could hook up Uppy to Transloadit, and it could export to Azure. But requires a paid subscription. I am happy to accept a PR for Uppy to enable direct Azure blob storage uploads however! (does this work with signing URLs also?)

Yes, Azure supports Shared Access Signature (SAS) tokens. [1]

I'm afraid my Javascript is rather poor but I'll happily look at what it would take to create a plugin for Azure this weekend. Presumably the S3 multi-part uploader and associated companion server would be a good base to understand the flow?

[1]: https://docs.microsoft.com/en-us/azure/storage/common/storag...

I see, that would be amazing! Yes, it would, to give a head start:

  npm i && npm run bootstrap && npm run dev:with-companion

Then visit http://localhost:3452 and it should get you a working dev environment with auto-reloads and all that jazz.