What are Ingots?

An ingot is Fe’s unit of code organization and distribution, similar to a “crate” in Rust or a “package” in other languages. Every Fe project is an ingot, and ingots can depend on other ingots.

Why Ingots?

Ingots provide several benefits:

• Code Organization: Group related code into logical units
• Reusability: Share code between projects as dependencies
• Encapsulation: Control what’s exposed publicly vs kept internal
• Versioning: Track and manage versions of shared code

Ingot Structure

Every ingot has:

1. A manifest file (fe.toml) that defines metadata and dependencies
2. A source directory (src/) containing Fe source files
3. An entrypoint (src/lib.fe) that defines what the ingot exports

my-ingot/
├── fe.toml        # Manifest with name, version, dependencies
└── src/
    ├── lib.fe     # Entrypoint - exports public items
    └── utils.fe   # Additional source files

Ingots vs Contracts

An ingot is a collection of code. It may contain contracts, but it’s not limited to them:

• Contracts are deployed to the blockchain
• Ingots organize code and can contain contracts, structs, functions, and more

A single ingot might contain:

• Multiple contracts
• Shared utility functions
• Common type definitions
• Message definitions for contract interfaces

Using Ingots

When you create a Fe project, you’re creating an ingot. When you add dependencies, you’re pulling in other ingots. The ingot system makes it easy to:

• Start new projects with a standard structure
• Share common patterns across projects
• Build on community-developed libraries

The following sections cover the details of project structure, dependency management, and publishing your own ingots.