# A native Rust library for Mozilla's Public Suffix List
[](https://github.com/rushmorem/publicsuffix/actions/workflows/ci.yml) [](https://crates.io/crates/publicsuffix) [](https://docs.rs/publicsuffix)
This library uses Mozilla's [Public Suffix List](https://publicsuffix.org) to reliably determine the suffix of a domain name. This crate provides a dynamic list that can be updated at runtime. If you need a faster, though static list, please use the [psl](https://crates.io/crates/psl) crate instead.
*NB*: v1 of this crate contained logic to validate domain names and email addresses. Since v2, this functionality was moved to the [addr](https://crates.io/crates/addr) crate. This crate also no longer downloads the list for you.
## Setting Up
Add this crate to your `Cargo.toml`:
```toml
[dependencies]
publicsuffix = "2"
```
## Examples
```rust
use publicsuffix::{Psl, List};
// the official list can be found at
// https://publicsuffix.org/list/public_suffix_list.dat
let list: List = "<-- your public suffix list here -->".parse()?;
let suffix = list.suffix(b"www.example.com")?;
assert_eq!(suffix.as_bytes(), b"com");
assert_eq!(suffix.typ(), Some(Type::Icann));
let domain = list.domain(b"www.example.com")?;
assert_eq!(domain.as_bytes(), b"example.com");
assert_eq!(domain.suffix().as_bytes(), b"com");
let domain = list.domain("www.食狮.中国".as_bytes())?;
assert_eq!(domain.as_bytes(), "食狮.中国".as_bytes());
assert_eq!(domain.suffix().as_bytes(), "中国".as_bytes());
let domain = list.domain(b"www.xn--85x722f.xn--55qx5d.cn")?;
assert_eq!(domain.as_bytes(), b"xn--85x722f.xn--55qx5d.cn");
assert_eq!(domain.suffix().as_bytes(), b"xn--55qx5d.cn");
let domain = list.domain(b"a.b.example.uk.com")?;
assert_eq!(domain.as_bytes(), b"example.uk.com");
assert_eq!(domain.suffix().as_bytes(), b"uk.com");
let domain = list.domain(b"_tcp.example.com.")?;
assert_eq!(domain.as_bytes(), b"example.com.");
assert_eq!(domain.suffix().as_bytes(), b"com.");
```