You do not need to run a Witnet node to use Witnet from your Ethereum smart contracts.
If you are a smart contracts developer, what you probably want is to use one of the data feeds, a randomness source, or to connect to APIs with HTTP GET/POST.
The Witnet mainnet is totally permissionles and open for anyone to join and and independently run their own node.
Like in many other blockchains, the activity of running a validator node and participating in block proposing is usually called mining.
Every time a block proposer gets 1 block accepted into the blockchain by the rest of the nodes in the network, they independently mint 250 new units of Wit tokens out of the blue.
Additionally, nodes that successfully participate in solving data requests get rewards in form of Wit tokens. These are not freshly minted — they are paid by the creators of the data requests as a mean to incentivize the miners to solve their requests.
There are multiple ways to run a Witnet validator node. Listed below are the most common methods, with tutorials on how to get started real quick:
It is important to understand that mining is a totally decentralized activity, and that you are the only one responsible of ensuring uptime and performance of your node.
Nobody can guarantee that running Witnet nodes will be ever profitable to you, as that largely depends on your own operation costs, the reliability of your infrastructure, and ultimately, luck.
It is perfectly normal for a new node to show 0 balance, reputation, blocks included or accepted commits for the first days (or weeks!) of it being up.
Please be patient, new identities in the system are subject to a slow start for critical security reasons
Also, please read below for tips on how to efficiently manage your Witnet node and how to increase your its probability of mining: