ULID (Universally Unique Lexicographically Sortable Identifier) is a 26-character string format that combines a timestamp with random data to create identifiers that are both unique and sortable by creation time. ULIDs are an alternative to UUIDs with better sorting capabilities.

Why use ULIDs instead of UUIDs?

ULIDs offer several advantages over UUIDs: they are lexicographically sortable by generation time, they use a more compact representation (26 characters vs 36 for UUIDs), they're case-insensitive, and they avoid problematic characters like hyphens.

How do I convert a UUID to a ULID?

You can convert a UUID to a ULID using our UUID Converter tool. Simply paste your UUID into the input field and click Convert. The tool supports UUID v1, v4, v7, and any hex string, converting them losslessly to ULID format and back.

Can I decode a ULID to see its timestamp?

Yes, you can decode a ULID using our ULID Decoder tool. It will show you the timestamp in various formats (Unix timestamp, ISO string, human-readable date) and the random component in different representations.

Are ULIDs suitable for database primary keys?

Yes, ULIDs are excellent for database primary keys. They're sortable by creation time which improves database performance, they're URL-safe, and they can be generated without a central coordinator, making them ideal for distributed systems.

What is NanoID and when should I use it?

NanoID is a tiny, secure, URL-friendly unique string ID generator. It's smaller and faster than UUID and is ideal for generating short unique IDs for URLs, session tokens, or any situation where a compact random identifier is needed. Unlike ULID, NanoID is not time-sortable.

What is a Snowflake ID?

Snowflake ID is a 64-bit unique identifier format originally developed by Twitter. It encodes a timestamp, datacenter ID, machine ID, and sequence number. Snowflake IDs are sortable by time, extremely fast to generate, and widely used in distributed systems like Twitter, Discord, and Instagram.

How do I decode a JWT token?

Paste your JWT token into our JWT Decoder tool to instantly see the decoded header, payload, and signature. The tool shows all claims including expiry time (exp), issued-at (iat), and custom claims. No data is sent to any server - decoding is done entirely in your browser.

What is CUID and CUID2?

CUID (Collision-resistant Unique Identifier) is designed for horizontal scalability and sequential IDs for databases and distributed systems. CUID2 is the improved next generation with better security and randomness properties. Both are excellent alternatives to UUID for Node.js applications.

ULID Generator

Generate Universally Unique Lexicographically Sortable Identifiers with high performance

193,000,000

ULIDs Generated

1,500

ULIDs/Second

150

Active Users

Generate ULID Why ULID?

Tools Menu

CUID & CUID2 Generator

Generate cryptographically secure CUID and CUID2 identifiers. CUID2 is designed to be secure, collision-resistant, URL-safe, and highly unpredictable.

CUID & CUID2 Generator -

Generate collision-resistant, secure, sequential unique identifiers for scale

Generator Settings

CUID Version

CUID2 Length (Characters) 24

Quantity 1

CUID Structural Anatomy

CUID2 is highly secure, utilizing dynamic salt hashing to ensure cross-process unpredictability and collision resistance.

CUID2 vs CUID vs UUID

Feature	CUID2	CUID (v1)	UUID v4
Unpredictability	Yes (Very High)	No Moderate	Yes High
Collision resistant	Yes (Extremely High)	Yes High	Yes High
URL Safe	Yes	Yes	No (hyphens)
Customizable length	Yes (2 to 32)	No (always 25)	No (always 36)
HTML/CSS friendly	Yes (starts with letter)	Yes (starts with c)	No (can start with digit)

Why CUID2 was created?

The original CUID (v1) had vulnerabilities where attackers could predict future IDs if they knew the generation algorithm and sequence. CUID2 solves this predictability issue by using custom entropy pools, modern hashing algorithms, and removing sequential counter components, making it virtually impossible to guess IDs while retaining its non-collision properties.

Ideal Use Cases

Database primary keys in distributed systems
Public-facing URLs, route parameters, and slug IDs
HTML element ID tags (since they always start with a letter)
Asynchronous backend batch processing identification

Related tools: ULID Generator UUID Converter NanoID Generator

Free Online Developer Tools – ULID, UUID, NanoID, CUID, Snowflake ID, JWT Decoder, Base64, JSON Formatter & More