UUID Formatter

What is a UUID Formatter

The same 128 bits can be written in many ways and every ecosystem picked a favourite. The canonical form is lowercase 8-4-4-4-12 with hyphens. .NET wraps the value in braces, logs usually drop the hyphens, URLs prefer something shorter than 36 characters, C# source wants a byte array, and PostgreSQL wants a typed literal before it will treat the string as a uuid.

This formatter accepts any of those spellings and rewrites every line into the one you select. It is the quickest way to normalise a column of mixed-case identifiers before comparing them, or to produce the exact literal a migration script or a config file needs.

How to

1. Paste the UUIDs, one per line — case, hyphens, braces and surrounding quotes are all tolerated.
2. Pick the output format. The list is rewritten as soon as you change it.
3. Use Copy all or Download .txt; lines that are not UUIDs are skipped and counted in the toast.

Use cases

• Case and hyphen mismatches: a database stores lowercase, logs emit uppercase, and a JOIN fails silently.
• API and URL payloads: 22-character base64url instead of a 36-character canonical string.
• Source code and migrations: a C# byte[], a typed SQL literal, or a bare 32-hex key for a legacy column.

Compare UUID Formatter with other formats

Code examples

JavaScript

const hex = '550e8400e29b41d4a716446655440000';
const H = (s) => `${s.slice(0,8)}-${s.slice(8,12)}-${s.slice(12,16)}-${s.slice(16,20)}-${s.slice(20)}`;

H(hex);                                  // 550e8400-e29b-41d4-a716-446655440000
H(hex).toUpperCase();                    // 550E8400-E29B-41D4-A716-446655440000
Buffer.from(hex, 'hex').toString('base64url');  // 22 characters

Python

import uuid, base64

u = uuid.UUID('550e8400-e29b-41d4-a716-446655440000')

str(u)                          # 550e8400-e29b-41d4-a716-446655440000
str(u).upper()                  # 550E8400-E29B-41D4-A716-446655440000
u.hex                           # 550e8400e29b41d4a716446655440000
u.bytes.hex()                   # same, as raw bytes
base64.urlsafe_b64encode(u.bytes).rstrip(b'=').decode()   # UQ6EAO4pQdSnFkZmVUQA

PostgreSQL

SELECT '550e8400-e29b-41d4-a716-446655440000'::uuid;      -- cast needs the hyphens
SELECT replace('550e8400-e29b-41d4-a716-446655440000','-','')::uuid;  -- still fine
SELECT uuid_extract_version('550e8400-e29b-41d4-a716-446655440000');

Frequently asked questions