Is there any websocket ethereum provider? Except etherscan one. Maybe there are paid wss subscriptions?
Use Infura.io to connect to different blockchains. You will need an account and project id.
Steps to create an Infura.io Project and remarks
1) Open Infura.io page and sign up for an account. On your dashboard, you now can create a new project.
2) Change the endpoint to Kovan and directly copy the endpoint URL for connecting to blockchain.
3) The web socket URL is slightly different from the http interface — the correct pattern for web services is:
Please, be aware that your personal API key to use Infura should be secret. So, don’t give it away to anyone else.
wss://mainnet.infura.io/ws wss://ropsten.infura.io/ws wss://rinkeby.infura.io/ws
Infura websocket support is now documented here.
From the intro:
Infura's websocket endpoint provides support for Pub/Sub API as well as JSON-RPC filter support.
QuikNode.io offers dedicated ETH nodes with https:// and wss:// endpoints.