# UTxO RPC (U5C) source
Read the chain from a [UTxO RPC](https://utxorpc.org) (U5C) endpoint — such as a local
[Dolos](https://github.com/txpipe/dolos) node or a hosted [Demeter](https://demeter.run)
endpoint — and print events to standard output.
## Pipeline
```mermaid
flowchart LR
src[U5C source] --> sink[Stdout sink]
```
- **Source** — `U5C`: connects to the gRPC `url`, starting from the chain tip. The
`metadata` table carries extra gRPC headers; leave it empty (`{}`) for a local
unauthenticated Dolos, or pass an API key for a hosted endpoint
(`metadata = { "dmtr-api-key" = "dmtr_..." }`).
- **Sink** — `Stdout`: prints each event.
## Prerequisites
- A running U5C endpoint (a local Dolos on `localhost:50051`, or a hosted U5C URL).
- Built with the `u5c` feature (it ships in the released binaries by default).
## Run
```sh
cd examples/dolos_source
oura daemon --config daemon.toml
```
From source:
```sh
cargo run --features u5c --bin oura -- daemon --config daemon.toml
```