Generate ULIDs instantly with our free online tool. Create Universally Unique Lexicographically Sortable Identifiers for databases, APIs & distributed systems.
Generate ULIDs instantly with our free online ULID generator tool. Create Universally Unique Lexicographically Sortable Identifiers that combine timestamps with cryptographically secure random data for database keys, distributed systems, and web applications.
A ULID (Universally Unique Lexicographically Sortable Identifier) is a unique identifier system that combines a timestamp with random data to create a 26-character string. Unlike traditional UUIDs, ULIDs are lexicographically sortable while maintaining cryptographic uniqueness and randomness, making them ideal for modern distributed applications.
Our ULID generator tool creates unique identifiers instantly:
A ULID identifier structure consists of two main parts:
The resulting 26-character string is encoded using Crockford's base32 alphabet (0-9 and A-Z, excluding I, L, O, and U).
The ULID is generated using the following steps:
The ULID generator performs the following steps:
ULID generators are essential for modern software development across multiple scenarios:
| Feature | ULID | UUID |
|---|---|---|
| Sortability | Lexicographically sortable | Not sortable |
| Timestamp | Includes millisecond timestamp | No timestamp (v4) |
| Length | 26 characters | 36 characters (with hyphens) |
| Encoding | Crockford's Base32 | Hexadecimal |
| Case Sensitivity | Case insensitive | Case insensitive |
Compare ULID generators with other unique identifier solutions:
Implement ULID generation across different programming languages:
1// JavaScript implementation
2function generateULID() {
3 const timestamp = Date.now().toString(36).padStart(10, '0');
4 const randomness = crypto.getRandomValues(new Uint8Array(16))
5 .reduce((acc, byte) => acc + byte.toString(36).padStart(2, '0'), '');
6 return (timestamp + randomness).toUpperCase();
7}
8
9console.log(generateULID());
101## Python implementation
2import time
3import secrets
4import base64
5
6def generate_ulid():
7 timestamp = int(time.time() * 1000).to_bytes(6, byteorder="big")
8 randomness = secrets.token_bytes(10)
9 return base64.b32encode(timestamp + randomness).decode("ascii").lower()
10
11print(generate_ulid())
121// Java implementation
2import java.security.SecureRandom;
3import java.time.Instant;
4
5public class ULIDGenerator {
6 private static final SecureRandom random = new SecureRandom();
7 private static final char[] ENCODING_CHARS = "0123456789ABCDEFGHJKMNPQRSTVWXYZ".toCharArray();
8
9 public static String generateULID() {
10 long timestamp = Instant.now().toEpochMilli();
11 byte[] randomness = new byte[10];
12 random.nextBytes(randomness);
13
14 StringBuilder result = new StringBuilder();
15 // Encode timestamp
16 for (int i = 9; i >= 0; i--) {
17 result.append(ENCODING_CHARS[(int) (timestamp % 32)]);
18 timestamp /= 32;
19 }
20 // Encode randomness
21 for (byte b : randomness) {
22 result.append(ENCODING_CHARS[b & 31]);
23 }
24 return result.toString();
25 }
26
27 public static void main(String[] args) {
28 System.out.println(generateULID());
29 }
30}
31These ULID code examples demonstrate implementation across popular programming languages. Adapt these functions for your specific applications or integrate them into larger systems requiring unique identifiers.
A ULID (Universally Unique Lexicographically Sortable Identifier) is a 26-character unique identifier that combines a timestamp with cryptographically secure random data. Unlike UUIDs, ULIDs maintain chronological order when sorted lexicographically.
Use our free ULID generator tool above to create unique identifiers instantly. Simply click the generate button to create new ULIDs, then copy the results for use in your applications.
ULIDs are sortable by creation time, use 26 characters with Crockford's Base32 encoding, and include timestamps. UUIDs are 36 characters (with hyphens), use hexadecimal encoding, and aren't naturally sortable.
Yes, ULID generators use cryptographically secure random number generation for the 80-bit randomness component, providing high collision resistance while maintaining temporal ordering.
Absolutely! ULIDs make excellent database primary keys because they're unique, naturally indexed by creation time, and don't require central coordination in distributed systems.
ULIDs use Crockford's Base32 encoding (0-9 and A-Z, excluding I, L, O, U) which is case-insensitive and URL-safe, making them ideal for web applications.
ULIDs are exactly 26 characters long, making them more compact than standard UUIDs (36 characters with hyphens) while providing the same level of uniqueness.
Yes, ULID generation works entirely offline since it only requires the current timestamp and a cryptographically secure random number generator - no network connectivity needed.
Start generating unique sortable identifiers now with our free ULID generator tool.
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