CLIENT ENGINE // AIR-GAPPED

UUID v4, UUID v7 & ULID Generator

Cryptographically secure RFC 9562 UUID v4, time-ordered UUID v7, and Crockford Base32 ULID bulk generator and timestamp decoder.

APPARATUS // UUID-GENERATOR VERIFIED OK // 0.0ms

Quick Reference Benchmarks

Specification Standard IETF RFC 9562 (May 2024)

UUID v4 Random Entropy 122 Bits (CSPRNG)

UUID v7 / ULID Timestamp 48-Bit Unix Epoch (ms)

ULID Encoding Alphabet 26-Char Crockford Base32

Execution Privacy 100% In-Browser Web Crypto

Overview & Background

Universally Unique Identifiers (UUIDs) and Universally Unique Lexicographically Sortable Identifiers (ULIDs) form the backbone of primary key generation in distributed databases, microservice event buses, and cloud-native storage engines. Historically standardized under IETF RFC 4122 and modernized in May 2024 under IETF RFC 9562, 128-bit UUIDs enable independent nodes to mint globally unique identifiers with zero central coordination and negligible collision probability.

While traditional UUID Version 4 relies on 122 bits of cryptographically random entropy, its completely random byte distribution causes severe B-tree index fragmentation in relational databases such as PostgreSQL, MySQL InnoDB, and SQL Server. Every random insert forces the storage engine to split mid-tree pages and flush non-sequential disk blocks. RFC 9562 solved this architectural bottleneck by introducing UUID Version 7 (UUIDv7), which embeds a 48-bit big-endian Unix Epoch millisecond timestamp in the most significant bits followed by 74 bits of cryptographic randomness. UUIDv7 preserves full 128-bit wire compatibility with existing UUID columns while guaranteeing monotonic, append-only B-tree index locality.

Kitiverse's UUID & ULID Generator executes 100% client-side using your browser's hardware-backed Web Crypto API (crypto.getRandomValues). Developers can generate single or bulk batches of up to 500 identifiers at once, toggle hyphens, braces, or uppercase formatting, and inspect any existing UUID or ULID to extract its embedded RFC version, variant bits, and exact UTC millisecond creation timestamp with zero remote server calls, zero account walls, private client-side compute, and local device storage.

How to generate and inspect UUID v4, UUID v7, and ULID identifiers

Mint cryptographically random or time-ordered primary keys and decode embedded timestamps directly in local browser memory.

Select your target identifier standard: UUID v4 for pure 122-bit randomness, UUID v7 for RFC 9562 time-ordered database keys, or ULID for compact 26-character Base32 strings.

Set your desired batch quantity (from 1 to 500 identifiers) and customize formatting options including hyphens, uppercase hex characters, or Microsoft-style curly braces.

Click 'Generate Batch' to populate fresh cryptographically secure identifiers, then click 'Copy All' or 'Download .txt' to export them into your migration script or test fixture.

Paste any existing UUID v4, UUID v7, or ULID into the bottom Inspector field to validate its structure and decode the exact UTC millisecond timestamp embedded inside UUID v7 and ULID keys.

Frequently Asked Questions

What is the difference between UUID v4 and UUID v7 in database performance?

UUID v4 generates 122 purely random bits, meaning every new record is inserted at a random location inside a database B-tree index, causing frequent page splits and random disk I/O. UUID v7 (standardized in IETF RFC 9562) places a 48-bit Unix millisecond timestamp in the leading bytes so new records always append to the right-most leaf page of the B-tree index, matching auto-increment BIGINT insert throughput while remaining globally unique.

How does a ULID differ from a standard UUID?

Both UUIDs and ULIDs are 128-bit identifiers, and both ULID and UUID v7 start with a 48-bit millisecond timestamp. However, instead of formatting the 128 bits as a 36-character hexadecimal string with hyphens, ULID encodes the bits using Crockford's Base32 alphabet into a compact, URL-safe, case-insensitive 26-character string that is lexicographically sortable as plain text.

How are UUIDs generated securely in the browser without a backend server?

Kitiverse invokes the W3C Web Crypto API (crypto.getRandomValues), which draws entropy directly from your operating system's kernel CSPRNG (/dev/urandom on macOS/Linux, CryptGenRandom/BCryptGenRandom on Windows). This provides true cryptographic unpredictability without ever transmitting generated keys over the network.

Can I extract the creation date and time from a UUID v7 or ULID?

Yes. Because both UUID v7 and ULID store a 48-bit big-endian Unix Epoch timestamp in milliseconds in their leading bits, pasting any UUID v7 or ULID into the Inspector field at the bottom of the tool immediately decodes the exact UTC ISO-8601 timestamp and epoch millisecond integer.

What is the probability of a collision when generating UUID v4 values?

With 122 bits of cryptographic entropy, there are 5.3 undecillion (5.3 × 10^36) possible UUID v4 values. You would need to generate roughly 1 billion UUIDs per second for 85 years straight to reach a 50% probability of a single collision.

Is this UUID generator free and private for production database seeding?

Yes. Kitiverse is 100% registration-free, zero account walls, private client-side compute, and local device storage. None of the identifiers you mint or inspect are logged or transmitted to any server.

Related Instruments in This Workbench

All Developer Utilities Tools →

Developer Utilities →

JSON Formatter & Validator

Prettify, validate, and minify JSON payloads in real time with line-by-line syntax error diagnostics. 100% registration-free, zero account walls, private client-side compute, local device storage.

Developer Utilities →

JWT Parser & Debugger

Decode, inspect, and verify JSON Web Tokens (JWT) client-side in real time. Features human-readable expiration countdowns, standard claims analysis, Web Crypto HMAC verification, and 100% zero-telemetry privacy.

Developer Utilities →

Base64 & Base64URL Encoder / Decoder

RFC 4648 Base64 and URL-safe Base64URL encoder and decoder with native multi-byte UTF-8 Unicode support and Data URI formatting.

Developer Utilities →

CSS Fluid Typography & Type Scale Generator

Calculate harmonious modular font hierarchies and zero-breakpoint CSS clamp() fluid typography variables that scale smoothly from mobile to desktop.

Text & Content →

Case Converter & URL Slug Generator

Transform code identifiers, database columns, and headings across 10 naming conventions including camelCase, snake_case, kebab-case, and SEO URL slugs.

Text & Content →

Mojibake Decoder & CJK Width Converter

Repair corrupted double-encoded UTF-8, Windows-1252, Cyrillic CP1251, and Greek ISO-8859-7 text strings, and convert East Asian CJK Full-Width and Half-Width characters.

Client-Side Execution & Verification Note:

This utility runs 100% locally in your browser with local device storage and zero server uploads. All outputs are provided on an "as-is" basis—please validate critical data, code, and files before deploying to production.