Developer knowledge base

UUID guides by language and task

Start with the job you need to do: generate an identifier in code, choose a database key, validate input, or convert a UUID without changing its value.

Generate and inspect UUIDs

Choose a version, generate a batch, or inspect an existing identifier.

UUID v4 Generator

Generate random UUID v4 values and learn when version 4 is the right default for APIs, records, fixtures and public identifiers.

Time-ordered UUIDs

UUID v7 Generator

Generate UUID v7 values for databases, logs and event streams where natural time ordering matters.

Name-based UUIDs

UUID v5 Generator

Generate deterministic UUID v5 values from a namespace and a name using SHA-1. The same inputs always produce the same UUID.

MD5 name-based UUIDs

UUID v3 Generator

Generate deterministic UUID v3 values from a namespace and a name using MD5, for legacy systems that expect version 3 identifiers.

Batch generation

Bulk UUID Generator

Generate lists of UUIDs or GUIDs for seed data, tests, spreadsheets, imports and QA workflows.

Inspect any UUID

UUID Decoder

Decode a UUID to reveal its version, variant and, for time-based UUIDs, the exact timestamp encoded inside it.

Validation patterns

UUID Regex Guide

Copy practical UUID regex patterns and learn what they validate, what they miss, and when a parser is safer than a regular expression.

Terminology guide

UUID vs GUID

Understand the difference between UUID and GUID, why both names exist, and how to handle them across Microsoft and web systems.

Generate UUIDs in your language

Use runtime APIs and libraries in application code, with parsing and compatibility notes.

Generate UUIDs in JavaScript

Generate UUIDs in modern JavaScript with crypto.randomUUID, browser-safe fallbacks and practical validation notes.

Generate UUIDs in Python

Use Python UUID examples for uuid4, validation, database storage and API output.

PHP UUID Generator: UUID v4 Examples

Create UUID v4 values with plain PHP, Composer or Laravel, then validate input and choose a consistent database representation.

Generate UUIDs in Go

Generate UUIDs in Go with the google/uuid package, including UUID v4, UUID v7, parsing and validation.

Generate UUIDs in Rust

Generate UUIDs in Rust with the uuid crate, including UUID v4, UUID v7, parsing and feature flags.

Generate UUIDs in Java

Generate UUIDs in Java with java.util.UUID, parse strings, and add UUID v7 with a maintained library.

Generate UUIDs (GUIDs) in C#

Generate GUIDs in C# with Guid.NewGuid, parse and validate them, and create UUID v7 on .NET 9 and later.

Generate UUIDs in TypeScript

Generate UUIDs in TypeScript with crypto.randomUUID in browsers and Node, plus typed validation helpers.

Generate UUIDs in Ruby

Generate UUIDs in Ruby with SecureRandom.uuid, validate strings, and use UUIDs in Rails models.

Generate UUIDs in Kotlin

Generate UUIDs in Kotlin via Java interop or the multiplatform kotlin.uuid API, with parsing examples.

Generate UUIDs in C++

Generate UUIDs in C++ using Boost.UUID, with random v4 generation and string conversion examples.

Generate UUIDs in Bash and the Terminal

Generate UUIDs from the command line with uuidgen or /proc, including lowercase output and bulk generation.

Store UUIDs in databases

Compare native storage types, byte ordering and primary-key choices before changing a schema.

Storage decisions

Best UUID Version for Databases

Choose between UUID v4, UUID v7, database sequences and public IDs for real application tables.

Generate UUIDs in SQL Server, PostgreSQL and MySQL

Use UUIDs in SQL databases with practical notes for PostgreSQL, SQL Server, MySQL and indexing.

MongoDB UUID Generator and Storage Guide

Generate UUIDs in mongosh, use BSON UUID values as document IDs, and avoid mismatches between strings and binary UUIDs.

SQL UUID output

SQL UUID Generator

Generate UUIDs and copy SQL-friendly INSERT values for seed data and database tests.

Format and export identifiers

Preserve the UUID value while changing its text representation or export format.

Format converter

UUID Converter

Convert UUIDs between hyphenated, compact, uppercase, lowercase, GUID braces and URN formats in your browser.

UUID Without Hyphens

Remove UUID hyphens or add hyphens back to compact UUID strings directly in the browser.

Uppercase UUIDs

UUID Uppercase Converter

Convert lowercase UUIDs to uppercase UUIDs and copy uppercase UUID or GUID values.

Lowercase UUIDs

UUID Lowercase Converter

Convert uppercase UUIDs to lowercase UUIDs and normalize pasted UUID or GUID values.

JSON UUID output

UUID JSON Generator

Generate UUIDs and copy them as JSON objects, JSON arrays or downloadable JSON files.

CSV UUID output

UUID CSV Generator

Generate UUID lists as a CSV column for spreadsheets, imports, fixtures and QA data.

Base58 / Base64url tool

Short UUID Generator & Converter

Shorten a UUID to a compact Base58 or Base64url string in your browser, without losing any information, and learn when a shorter ID is worth it.

Compare UUIDs with other IDs

Check ordering, text length and collision tradeoffs for ULID and Nano ID.

Comparison guide

UUID vs ULID

Compare UUID and ULID for database keys and distributed IDs, including sortability, encoding, size and when UUID v7 closes the gap.

Comparison guide

UUID vs Nano ID

Compare UUID and Nano ID for unique identifiers: length, collision safety, URL friendliness and when each is the better fit.

Sortable identifiers

ULID Generator

Generate ULIDs online: 26-character, lexicographically sortable identifiers with a millisecond timestamp, created privately in your browser.

Compact random IDs

Nano ID Generator

Generate Nano IDs online: compact, URL-safe, collision-resistant random identifiers with a configurable length, created privately in your browser.

Privacy and production use

Understand browser generation, offline behavior, collision risk and authorization boundaries.

Are UUIDs Secure?

Learn what UUIDs protect, what they do not protect, and how to use UUIDs safely in URLs, APIs and databases.

Reliability guide

UUID Collision Probability

Understand how unlikely UUID collisions are, what causes real duplicate ID incidents, and how to design safer systems.

Frontend-only UUIDs

No-Backend UUID Generator

Generate UUIDs without a backend API, account, database or server-side UUID storage.

Browser UUID generation

Client-Side UUID Generator

Generate UUIDs using client-side browser JavaScript with no UUID upload or backend storage.

Installable UUID tool

Offline UUID Generator

Use the UUID generator offline after first load and install it as a small browser app.

Architecture and production decisions

For broader design decisions and common production mistakes, read the UUID blog.