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

# Libraries

> Learn the differences between Abstract and Ethereum libraries.

The addresses of deployed libraries must be set in the project configuration.
These addresses then replace their placeholders in
IRs: `linkersymbol` in Yul and `PUSHLIB` in EVM legacy assembly.

A library may only be used without deployment if it has been inlined by the optimizer.

<Card title="Compiling non-inlinable libraries" icon="file-contract" href="https://docs.zksync.io/build/tooling/hardhat/compiling-libraries">
  View the ZK Stack docs to learn how to compile non-inlinable libraries.
</Card>