Smart Contract Library

1 min read

Pronunciation

[smahrt kon-trakt ly-brer-ee]

Analogy

A smart contract library is like a shared utility toolbox—contracts borrow its tools without reinventing them.

Definition

A reusable contract containing common functions that can be statically linked or deployed once and referenced via `delegatecall`.

Key Points Intro

Libraries promote code reuse through:

Key Points

Stateless functions: No storage, only pure/view logic.

Deployment options: Linked at compile time or via `DELEGATECALL`.

Gas savings: Shared code reduces duplication.

Versioning: Immutable once deployed, careful upgrade needed.

Example

’s `SafeMath` library provides `add`, `sub` with overflow checks for multiple contracts.

Technical Deep Dive

When a library is linked, its is inserted into the ’s placeholder. `DELEGATECALL` executes library code in caller’s context, preserving `msg.sender` and storage. Library functions must be internal or public pure/view to avoid unintended changes.

Security Warning

Library bugs propagate to all dependent contracts; audit libraries thoroughly.

Caveat

Libraries cannot hold ; complex logic may require contract instead.

Related Terms

OpenZeppelin

DelegateCall

ABI

Blockchain & Cryptocurrency Glossary

Smart Contract Library - Related Articles