How to Generate UUID in Dart/Flutter

How to Generate a UUID in Dart

Dart's core SDK has no built-in UUID generator, so the standard approach is the uuid package from pub.dev — add it to pubspec.yaml, then call Uuid().v4() for a random, RFC 4122-compliant identifier. See the go uuid page for UUID primary keys in GORM and pgx with optimal PostgreSQL storage.

pubspec.yaml

dependencies:
  uuid: ^4.0.0  # check pub.dev for the latest version

main.dart

import 'package:uuid/uuid.dart';

final uuid = Uuid();

void main() {
  final myUuid = uuid.v4();
  print(myUuid);
  // Output: 550e8400-e29b-41d4-a716-446655440000
}

Explanation

uuid: ^4.0.0 in pubspec.yaml pulls in the package — run dart pub get or flutter pub get afterward to install it.
import 'package:uuid/uuid.dart' exposes the Uuid class; create one instance and reuse it rather than instantiating Uuid() on every call.
uuid.v4() generates a random UUID using a cryptographically secure random source and returns it as a plain String.
print(myUuid) outputs the standard 36-character hyphenated format directly — there's no separate object-to-string conversion step needed.

Convert a String to a UUID in Dart

Dart's uuid package treats UUIDs as plain strings — there's no dedicated UUID class to parse into, so "converting" really means validating that a string matches the UUID format before you trust it, using the package's Uuid.isValidUUID() static helper. The scala uuid reference explains how to use UUID.randomUUID() in idiomatic Scala with type safety.

main.dart

import 'package:uuid/uuid.dart';

void main() {
  const input = '550e8400-e29b-41d4-a716-446655440000';

  if (Uuid.isValidUUID(fromString: input)) {
    print('Valid UUID: $input');
  } else {
    print('Invalid UUID format');
  }
}

Explanation

Uuid.isValidUUID(fromString: input) is a static method — call it directly on the Uuid class, no instance required.
It returns a plain bool, so wrap any untrusted input (form fields, query parameters, JSON bodies) in this check before treating it as a valid identifier.
Pass a validationMode such as ValidationMode.strictRFC4122 when you need to reject non-standard variants, not just malformed strings.
Since Dart has no built-in UUID type, a validated string is the closest thing to a "parsed" UUID you'll get — store and compare it as a String.

Other Options for Generating UUIDs in Dart

The same uuid package that generates v4 identifiers also covers timestamp-based and deterministic UUIDs, so there's no extra dependency to add when your use case calls for something other than random.

main.dart

import 'package:uuid/uuid.dart';

final uuid = Uuid();

void main() {
  // Version 1 - timestamp + node ID, sortable by creation time
  final uuidV1 = uuid.v1();

  // Version 5 - deterministic, same namespace + name always produce the same UUID
  final uuidV5 = uuid.v5(Uuid.NAMESPACE_URL, 'https://example.com');
}

Explanation

uuid.v1() embeds the current timestamp plus a node identifier, so IDs generated in sequence sort chronologically — avoid it for public-facing IDs since the timestamp can be inferred.
uuid.v5(namespace, name) hashes a namespace UUID and a name string with SHA-1, producing the exact same UUID every time for the same inputs — useful for content-addressed identifiers.
Both methods live on the same Uuid instance as v4(), so no additional package or import is required to use them.
Built-in namespace constants like Uuid.NAMESPACE_URL and Uuid.NAMESPACE_DNS save you from generating your own namespace UUID for common cases.

Generate UUID in Dart

How to Generate a UUID in Dart

Explanation

Convert a String to a UUID in Dart

Explanation

Other Options for Generating UUIDs in Dart

Explanation

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