How to Generate UUID in Rust

How to Generate a UUID in Rust

The most common way to generate a UUID in Rust is Uuid::new_v4() from the uuid crate, which produces a random, cryptographically secure 128-bit identifier. Add the crate to Cargo.toml with the v4 feature enabled — no other setup required. For native UUID column type and gen_random_uuid() support, see the postgresql uuid guide.

Cargo.toml

[dependencies]
uuid = { version = "1", features = ["v4"] }

main.rs

use uuid::Uuid;

fn main() {
    let my_uuid = Uuid::new_v4();
    println!("{}", my_uuid);
    // Output: 550e8400-e29b-41d4-a716-446655440000
}

Explanation

uuid = { version = "1", features = ["v4"] } in Cargo.toml pulls in only the v4 code path, keeping your compiled binary small.
Uuid::new_v4() generates a random UUID using the getrandom crate under the hood, which draws from your OS's cryptographically secure random source.
The {} format specifier calls Uuid's Display implementation, printing the standard 36-character hyphenated form automatically.
Uuid implements Copy, so passing it around your codebase never requires cloning or borrowing.

Convert a String to a UUID in Rust

When a UUID arrives as a string — from a request body, a config file, or a database row — parse it back into a type-safe Uuid with Uuid::parse_str(). To generate uuid online securely, the tool uses the Web Crypto API so every output is cryptographically random.

main.rs

use uuid::Uuid;

fn main() {
    let my_uuid = Uuid::new_v4();
    let uuid_str = my_uuid.to_string();

    // Parse the string back into a Uuid
    let parsed = Uuid::parse_str(&uuid_str).expect("invalid UUID");
    assert_eq!(my_uuid, parsed);
}

Explanation

Uuid::parse_str() returns a Result<Uuid, uuid::Error>, so invalid input never panics silently — handle the Err case explicitly instead of calling .expect() in production code.
The parser accepts UUIDs with or without hyphens, in either uppercase or lowercase.
Uuid implements PartialEq, so two parsed UUIDs compare equal with == when they represent the same value.
Use Uuid::try_parse() (added in uuid 1.3) for a faster, allocation-free parse when you don't need detailed error messages.

Other Options for Generating UUIDs in Rust

The uuid crate supports every UUID version through Cargo feature flags, so you only compile in what you use. Enable v7 for a time-sortable UUID that improves database index performance, or v1 for a timestamp-plus-node-ID identifier. Use the c++ uuid guide to implement UUID generation in C++ with Boost.UUID or the platform-native APIs.

Cargo.toml

[dependencies]
uuid = { version = "1", features = ["v4", "v7", "serde"] }

main.rs

use uuid::Uuid;

// Version 7 - Unix timestamp + random, sortable and index-friendly
let uuid_v7 = Uuid::now_v7();

// Version 1 - timestamp + node ID (needs an explicit context/clock source)
// let uuid_v1 = Uuid::new_v1(timestamp, &node_id);

Explanation

Adding "v7" to the features list unlocks Uuid::now_v7(), which encodes the current Unix millisecond timestamp in the most significant bits — ideal for database primary keys.
"v1" unlocks Uuid::new_v1(), which needs an explicit timestamp and node ID source since Rust has no implicit "current MAC address" API.
Adding "serde" derives Serialize/Deserialize for Uuid, so it works directly in any serde-compatible format (JSON, MessagePack, etc.) without a manual wrapper type.
Only enable the features you actually use — each one adds a small amount to your compiled binary size.

Generate UUID in Rust

How to Generate a UUID in Rust

Explanation

Convert a String to a UUID in Rust

Explanation

Other Options for Generating UUIDs in Rust

Explanation

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