Node architecture

The node itself consists of three distributed components: store, block-producer and RPC. We also provide a reference faucet implementation which we use to distribute testnet and devnet tokens.

The components can be run on separate instances when optimised for performance, but can also be run as a single process for convenience. At the moment both of Miden's public networks (testnet and devnet) are operating in single process mode.

The inter-component communication is done using a gRPC API wnich is assumed trusted. In other words this must not be public. External communication is handled by the RPC component with a separate external-only gRPC API.

RPC

The RPC component provides a public gRPC API with which users can submit transactions and query chain state. Queries are validated and then proxied to the store. Similarly, transaction proofs are verified before submitting them to the block-producer. This takes a non-trivial amount of load off the block-producer.

This is the only external facing component and it essentially acts as a shielding proxy that prevents bad requests from impacting block production.

It can be trivially scaled horizontally e.g. with a load-balancer in front as shown above.

Store

The store is responsible for persisting the chain state. It is effectively a database which holds the current state of the chain, wrapped in a gRPC interface which allows querying this state and submitting new blocks.

It expects that this gRPC interface is only accessible internally i.e. there is an implicit assumption of trust.

Block-producer

The block-producer is responsible for aggregating received transactions into blocks and submitting them to the store.

Transactions are placed in a mempool and are periodically sampled to form batches of transactions. These batches are proved, and then periodically aggregated into a block. This block is then proved and committed to the store.

Proof generation in production is typically outsourced to a remote machine with appropriate resources. For convenience, it is also possible to perform proving in-process. This is useful when running a local node for test purposes.

Faucet

A stand-alone binary which serves a webpage where users can request tokens from a customizable faucet account. The faucet communicates with the node via the RPC component and is not considered special by the node. It is a simple reference implementation of a faucet.