---
title: "Key concepts"
url: "/docs/learn-about-signet/key-concepts/index.md"
description: "The building blocks you'll use when developing on Signet."
---
# Key concepts

Signet is an EVM rollup that settles on Ethereum. Your application interacts with two chains simultaneously: Signet (the rollup) and Ethereum (the host chain). Deposits, swaps, and fills happen across both in the same block.

## The building blocks

**[Passage](/docs/learn-about-signet/cross-chain-transfers/index.md)** moves assets from Ethereum into Signet. Deposits arrive in the same block.

**[Orders](/docs/learn-about-signet/how-orders-work/index.md)** move assets from Signet back to Ethereum (or any chain). A filler delivers the output, and atomic settlement ensures both sides execute or neither does.

**[The transaction cache](/docs/learn-about-signet/how-orders-work/index.md#the-transaction-cache)** is how you submit transactions, signed orders, and bundles to Signet's sequencer infrastructure.

**[The Transactor](/docs/build-on-signet/advanced/execute-from-ethereum/index.md)** triggers execution on Signet from Ethereum with guaranteed, censorship-resistant inclusion.

## Synchronized settlement

Signet produces blocks synchronized with Ethereum. When your user deposits ETH via Passage on Ethereum, the tokens appear on Signet in the same block. When they create an order to exit, a filler delivers on Ethereum and the builder settles both sides atomically.

## Parmigiana testnet

[Parmigiana](/docs/build-on-signet/parmigiana/index.md) is Signet's public testnet. It has a faucet for test tokens, RPC endpoints, and all deployed contract addresses. Use it for development and testing.

## Next steps

Start with the [getting started guide](/docs/build-on-signet/getting-started/index.md) to set up your development environment.