Minio is your friend. (S3 compatible self-hosted, open-source object store).

I recently implemented a text/snippet sharing tool that uses Minio instead of S3, because I like to self-host everything.

https://minio.io/

I use this with Seafile to store data in Azure Blob storage - it was incredibly simple to setup and has been rock solid since. Highly recommended!

I'm curious, how do you use both seafile and minio?

Minio is an S3 proxy, allowing you to use different storage backends with systems that support S3-compatible blob storage (like Seafile).

In my case I have Minio in front of Azure blob storage, so Seafile is storing data in that.

I host Seafile and Minio using Docker Compose, which was super-simple to get started with.

FWIW, It took me about 5 minutes to get it going after I updated nodejs to version 10. It took me another 5 minutes to realize it setup a local filesystem storage in $TEMP automatically. I was impressed with how easy it was to get going, and that it picked sensible (though not well documented) defaults :)

The default npm install; npm start will give you a self-hosted app. The docker one is a different beast.