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.

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UUID / ULID Deep Byte Inspector & Parser

Dissect and inspect raw byte structures of UUIDs (v1-v8) and ULIDs

Unique ID (UUID / ULID)

Interactive Byte Map (16 Bytes / 128 Bits)

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Hover or tap on a byte above to view its internal bit structure and exact binary role.

Timestamp Bits

Version Indicator Bits

Variant Indicator Bits

Randomness / Entropy Bits

Clock Seq / Node Bits

Decoded Metadata Details

Identifier Type:UUID v4 (Random)

Embedded Timestamp:1780812345678 ms

UTC Date/Time:2026-06-07 07:25:45 UTC

Local Date/Time:2026-06-07 14:25:45 GMT+7

UUID Version:4

UUID Variant:RFC 4122 (Variant 1)

Clock Sequence:N/A

Node ID (MAC Address):N/A

Crockford Base32 (ULID equivalent)

Hyphenated Hex (UUID equivalent)

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ID 字节解析器

UUID / ULID Deep Byte Inspector & Parser

Interactive Byte Map (16 Bytes / 128 Bits)

Decoded Metadata Details