> ## Documentation Index
> Fetch the complete documentation index at: https://compact-by-example.org/llms.txt
> Use this file to discover all available pages before exploring further.
# First Application
> Build a counter DApp in Compact: the Counter ledger type, increment circuits, and public state on Midnight Network.
## Video Tutorial
## The Contract
```compact theme={null}
pragma language_version >= 0.23;
import CompactStandardLibrary;
// Public state visible on the blockchain
export ledger round: Counter;
// Circuit that increments the counter by 1
export circuit increment(): [] {
round.increment(1);
}
```
## How It Works
### Public Ledger State
```compact theme={null}
export ledger round: Counter;
```
`Counter` is a built-in type for counting operations. The value is publicly visible on the blockchain.
### The Increment Circuit
```compact theme={null}
export circuit increment(): [] {
round.increment(1);
}
```
`Counter` stores a non-negative integer and exposes `.increment(n)`, `.decrement(n)`, `.read()`, and comparison helpers like `.lessThan(n)`. This example only uses `.increment(1)`.
## What's Next
Explore all Compact data types
Back to the basics