> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sophon.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# ZK Stack Architecture (Legacy)

> The ZK Stack foundations of Sophon v1

<Warning>
  This page documents the legacy Sophon v1 chain architecture. The Sophon Chain is
  being wound down; see the [migration guide](/migration) for current actions.
</Warning>

Sophon v1 was a ZK Stack chain. The original architecture used ZKsync components to
execute transactions on Sophon, prove chain state to Ethereum, and participate in
the broader Elastic Chain design.

<img src="https://mintcdn.com/sophon-29bed8dc/0txbnStdv27i3LeR/images/zk/sophon-zk-stack.webp?fit=max&auto=format&n=0txbnStdv27i3LeR&q=85&s=1282259847f814fe8fa0ce2617cea11b" alt="Sophon ZK Stack architecture" width="2304" height="1296" data-path="images/zk/sophon-zk-stack.webp" />

## Original design goals

* **Scalability:** execute consumer-application transactions outside Ethereum.
* **Validity proofs:** use zero-knowledge proofs to verify batched state transitions
  on Ethereum.
* **External data availability:** store reconstructable chain data through Avail.
* **Interoperability:** align with ZKsync's Elastic Chain architecture for movement
  between ZK chains.

These points explain the technical thesis behind the legacy chain. Sophon's current
direction is product-led, with new applications built on Base rather than a new
general-purpose Sophon chain.