## Nodes and validators


<br>

- the validator is responsible for creating a new block and sending it out to other nodes on the network.
- to participate as a validators, a user must deposit 32 ETH into the deposit contract and run 3 pieces of software: - an execution client - a consensus client - a validator
- once activated, validators receive new blocsk from peers - the txs delivered in the block are re-executed, and the block signature is checked
- the validator then sends a vote (attestation) in favor of that block across the network
- the timing of blocks is not determined by the mining difficult anymore, but it's fixed:

    - slots (12 seconds)
    - epochs (32 slots)

- in every slot, a committee of validators is randomly chosen, whose votes are used to determine the validity of the block being proposed
- the first block in each epoch is a checkpoint

<br>

### Setting a dedicated hardware

<br>

* [Check estimate of the blockchain size](https://bitinfocharts.com/ethereum/)
* Minimum specs:
  - CPU with 4+ cores
  - 32 GB+ RAM
  - fast SSD with at least 1T free space
  - 25+ MBit/sec download internet service



<br>

### Clients

<br>


### The JSON-RPC interface

<br>

* the JSON-RPC API is an interface that allows us to write programs that use an Ethereum client as a gateway to an Ethereum network and blockchain.
* the RPC interface is offered as an HTTP service on port 8545. For security reasons it is restricted, by default, to only accept connections from localhost.

<br>

### Tools

<br>

* [Ethereum Beacon APIs](https://github.com/ethereum/beacon-apis)