RPC node

Every dApp, wallet or backend needs to talk to the network to read balances, query contracts or broadcast transactions. It does not do so against the chain directly, but against a node that exposes standard RPC methods (for example eth_getBalance or eth_sendRawTransaction on Ethereum), usually via JSON-RPC over HTTP or WebSocket, the latter for subscribing to real-time events.

Running your own node gives sovereignty and privacy, but requires hardware, syncing and continuous operation; an archive node, which keeps all historical state, is even heavier than a normal full node. That is why most projects use managed RPC providers like Alchemy, Infura or QuickNode, which offer reliable endpoints, scaling and enhanced APIs. The cost and dependence on a third party are the trade-off.

The RPC node is a critical point of the architecture: your product's ability to see the chain at all times depends on its availability. That is why production setups recommend redundancy, several providers with failover, and watching rate limits so a traffic spike does not leave the application unable to read. For heavy historical data or indexing, it is complemented with services like The Graph instead of overloading the RPC with queries it is not designed for.