Indexing Data on Sepolia Beacon Chain

Sepolia is a widely used Ethereum testnet, and its Beacon Chain is the consensus layer that coordinates validators on the test network. The Graph can stream that consensus-layer activity — blocks and epochs, validator activity, attestations, deposits, and slashings — as real-time data with Substreams.

Sepolia Beacon Chain is supported by The Graph with Substreams — a parallelized, real-time streaming engine for high-throughput use cases — via Pinax Network⁠.

Indexing Sepolia Beacon Chain with Substreams

Substreams is a parallelized, real-time streaming engine for extracting and transforming blockchain data. Where a Subgraph indexes into a hosted GraphQL API, Substreams lets you consume high-throughput data directly or via 10+ supported sinks. Substreams streams Sepolia Beacon Chain’s consensus-layer blocks — validators, attestations, deposits, and slashings. Modules are written in Rust and composed into reusable packages.

Find an Existing Module on Substreams.dev

Before writing any code, check the Substreams Registry⁠ for a package that already does what you need. The registry hosts community- and team-built modules covering common onchain data that you can run as-is or compose into your own pipeline. Search for the protocol or data you want on Sepolia Beacon Chain; if a module fits, you can consume its output directly or import it as a dependency in your own project.

Develop Your Own Substreams Module

If no existing module fits, you can build one. The Substreams Quick Start is the full walkthrough. In short:

1. Install the Substreams CLI and get an API key from Pinax Network⁠.
2. substreams init does not have a template for the Beacon Chain yet, so set up the project by hand: write a substreams.yaml manifest⁠ with network: sepolia-cl and a Rust map module that takes sf.beacon.type.v1.Block as its input (the protobuf definitions are published on Buf⁠).
3. Write your extraction and transformation logic in Rust, then run substreams build.
4. Stream the output with substreams gui (or substreams run) to iterate, then publish your package to the Substreams Registry⁠ to reuse or share it.