Philiprehberger.IdGenerator

Sortable, URL-safe unique ID generators — ULID, NanoID, and prefixed IDs.

Installation

dotnet add package Philiprehberger.IdGenerator

Usage

using Philiprehberger.IdGenerator;

// Generate a ULID (sortable, 26 chars)
var ulid = Id.NewUlid();
Console.WriteLine(ulid); // "01HXYZ..."

// Generate a NanoID (21 chars, URL-safe)
var nano = Id.NewNanoId();
Console.WriteLine(nano); // "V1StGXR8_Z5jdHi6B-myT"

// Generate a NanoID with custom size and alphabet
var custom = Id.NewNanoId(size: 10, alphabet: "0123456789abcdef");

// Generate a Stripe-style prefixed ID
var prefixed = Id.NewPrefixed("usr");
Console.WriteLine(prefixed); // "usr_01HXYZ..."

// Generate a short ID (12 chars)
var shortId = Id.NewShortId();
Console.WriteLine(shortId); // "a8f3kQ_9xZrT"

ULID

using Philiprehberger.IdGenerator;

var ulid = new Ulid();

// Extract timestamp
DateTimeOffset timestamp = ulid.Timestamp;

// Parse from string
var parsed = Ulid.Parse("01HXYZ...");

// Safe parsing
if (Ulid.TryParse("01HXYZ...", out var result))
{
    Console.WriteLine(result);
}

// Convert to GUID
Guid guid = ulid.ToGuid();

// ULIDs are sortable
var a = Id.NewUlid();
var b = Id.NewUlid();
Console.WriteLine(a < b); // true (a was created first)

Prefixed IDs

using Philiprehberger.IdGenerator;

// Create prefixed IDs for different entity types
var userId = PrefixedId.Create("usr");   // "usr_01HXYZ..."
var orgId = PrefixedId.Create("org");    // "org_01HXYZ..."

// Validate a prefixed ID
bool valid = PrefixedId.Validate("usr_01HXYZ...", "usr"); // true
bool wrong = PrefixedId.Validate("usr_01HXYZ...", "org"); // false

JSON Serialization

using System.Text.Json;
using Philiprehberger.IdGenerator;

var options = new JsonSerializerOptions();
options.Converters.Add(new UlidJsonConverter());

var ulid = Id.NewUlid();
var json = JsonSerializer.Serialize(ulid, options); // "\"01HXYZ...\""
var back = JsonSerializer.Deserialize<Ulid>(json, options);

API

Id (static factory)

Method	Description
NewUlid()	Generate a new ULID
NewNanoId(int size = 21, string? alphabet = null)	Generate a NanoID
NewPrefixed(string prefix)	Generate a prefixed ID
NewShortId(int length = 12)	Generate a short random ID

Ulid (readonly struct)

Member	Description
Ulid()	Create a new ULID with current timestamp
Timestamp	Extract the timestamp as DateTimeOffset
Parse(string)	Parse a ULID from a 26-char string
TryParse(string?, out Ulid)	Safely parse a ULID string
ToGuid()	Convert to a Guid
ToString()	26-char Crockford Base32 representation
==, !=, <, >, <=, >=	Comparison operators

NanoId (static)

Method	Description
Generate(int size = 21, string? alphabet = null)	Generate a random NanoID

PrefixedId (static)

Method	Description
Create(string prefix)	Create a prefixed ID with a ULID suffix
Validate(string id, string expectedPrefix)	Check prefix and ULID validity

UlidJsonConverter

Description
System.Text.Json converter for ULID serialization/deserialization

Development

dotnet build src/Philiprehberger.IdGenerator.csproj --configuration Release

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License

MIT