UUID Generator — Generate & Validate UUIDs Instantly

UUID Generator is a free, browser-based tool that creates cryptographically random UUID v4 identifiers in milliseconds. Generate one at a time or up to 100 in bulk, validate any UUID string, and copy output in standard, compact, or uppercase formats — no account, no install, zero backend.

The Problem

UUIDs show up everywhere in modern development: database primary keys, session identifiers, idempotency tokens, message IDs, S3 object keys, and API request IDs. Developers need them constantly — during local development, in test fixtures, when seeding databases, while debugging logs, and when writing documentation.

The typical workflow is painful:

• Open a browser and search "uuid generator online"
• Land on a tool buried under ads
• Click a button that generates one UUID
• If you need 20 UUIDs, click 20 times
• Manually concatenate or format them for your use case

Or worse, write a throwaway script just to get a list of UUIDs:

import uuid
for _ in range(20):
    print(uuid.uuid4())

And when a UUID in a log file or API response looks malformed, there's no quick way to validate it without reaching for a regex in a REPL.

How It Works

Generate Tab

Select a quantity (1, 5, 10, 25, 50, or 100), pick a format, click Generate. The tool uses the browser's crypto.randomUUID() API — the same cryptographically secure random number generator used by the operating system.

Each result appears in a list with a one-click copy button per UUID. A "Copy All" button copies the full list, newline-separated, ready to paste into a .env file, SQL seed script, or test fixture.

UUID Formats

The tool produces four output formats:

• Standard — lowercase with hyphens: 550e8400-e29b-41d4-a716-446655440000
• Compact — no hyphens: 550e8400e29b41d4a716446655440000 (32 chars, for CHAR(32) / BINARY(16) columns)
• Uppercase — with hyphens: 550E8400-E29B-41D4-A716-446655440000 (GUID-style)
• Uppercase compact — no hyphens, uppercase: 550E8400E29B41D4A716446655440000

A live format preview shows a sample UUID formatted as selected before you generate, so there's no guessing.

Validate Tab

Paste any UUID string — with or without hyphens, in any case, with or without surrounding {} braces (GUID format). The validator normalizes the input and returns:

• Valid / Invalid verdict
• UUID version (v1 through v7, where detectable)
• Three formatted outputs: lowercase, uppercase, compact

For invalid inputs, the validator explains the format requirement and flags common issues.

Key Features

• Cryptographically secure — uses crypto.randomUUID() / crypto.getRandomValues(), not Math.random()
• Bulk generation — 1, 5, 10, 25, 50, or 100 UUIDs in a single click
• Four output formats — standard, compact, uppercase, uppercase compact
• UUID validation — detect version, normalize format, copy fixed UUID
• Copy individual or all — one-click copy per UUID, plus a "Copy All" button
• Format preview — see output format before generating
• Fully client-side — nothing sent to any server, UUIDs never logged
• No signup required — open and use immediately

Technical Implementation

Core Technologies

• Next.js 16 with App Router
• TypeScript strict mode
• Tailwind CSS v4 with OKLCH color tokens
• shadcn/ui component library
• Framer Motion for tab transitions
• crypto.randomUUID() — the Web Crypto API

UUID Generation

UUID v4 generation uses the browser's crypto.randomUUID() where available, with a crypto.getRandomValues() polyfill for environments that don't yet expose the higher-level API:

function generateUUID(): string {
  if (typeof crypto !== "undefined" && crypto.randomUUID) {
    return crypto.randomUUID();
  }
  const bytes = new Uint8Array(16);
  crypto.getRandomValues(bytes);
  bytes[6] = (bytes[6] & 0x0f) | 0x40; // set version 4
  bytes[8] = (bytes[8] & 0x3f) | 0x80; // set variant bits
  const hex = Array.from(bytes)
    .map((b) => b.toString(16).padStart(2, "0"))
    .join("");
  return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
}

UUID Validation

Validation normalizes the input (strip braces, lowercase, handle missing hyphens for compact inputs) and tests against RFC 4122's canonical regex. Version detection reads the character at position 14 and maps it to the version string.

Architecture

• Two-tab UI (Generate / Validate) with animated transitions
• Quantity and format state managed in React with useState
• useCallback on generate and copy handlers to avoid unnecessary re-renders
• AnimatePresence for smooth tab switching with framer-motion
• sonner toast library for copy success feedback

Use Cases

Database Primary Keys

UUID v4 is a standard primary key format across PostgreSQL (UUID type), MySQL (CHAR(36) or BINARY(16)), and MongoDB. Generate a batch of UUIDs for seeding a test database, creating dummy records, or initializing a migration script.

API Testing and Development

Need to test an endpoint that expects a UUID in the path or body? Generate one in seconds. Need 50 unique IDs for load testing? Use bulk generation and paste the list directly into your test suite.

Environment Files and Configuration

Many configuration values — client IDs, webhook secrets, correlation tokens — are UUID-shaped. Generate them directly without leaving your browser.

Debugging Production Logs

A UUID in a log file looks malformed. Is it truncated? Is it a different format (compact, braces)? Paste it into the Validate tab to get an instant answer and a normalized version.

Documentation and Examples

Writing API documentation or README examples? Generate realistic-looking UUIDs that match the format your API actually produces. Using 00000000-0000-0000-0000-000000000000 (the nil UUID) everywhere is technically valid but makes documentation look contrived.

Learning and Teaching

For developers learning about UUID internals, the structure reference panel on the Validate tab shows which bit position encodes the version and variant. It makes the abstract spec tangible.

Why UUID Generator?

vs. Searching "uuid online"

Most results are ad-heavy, generate one at a time only, and don't support validation or multiple formats. UUID Generator generates up to 100 at once, validates inputs, and has no ads.

vs. Writing a Script

A Python or Node.js snippet works but requires a terminal, a runtime, and context-switching out of your browser. UUID Generator is one tab switch away.

vs. IDE Plugins

IDE UUID plugins are great when you're inside your editor. UUID Generator works from any device, any browser, with zero setup — including when you're on a colleague's machine or reviewing code on a tablet.

Privacy

Generating a UUID client-side ensures nothing is logged server-side. For UUIDs used as session tokens, idempotency keys, or internal identifiers where observability matters, client-side generation removes a potential audit concern.

Results

UUID Generator removes the friction from one of the most routine tasks in software development:

• Zero setup — open the URL, generate, copy
• Batch-ready — 100 UUIDs in the time it takes to click once
• Format-flexible — match the UUID format your system expects
• Validation built in — no separate tool or regex needed
• Private by design — crypto API in the browser, nothing leaves the tab

Try it now: uuid-generator.tools.jagodana.com