When you need a GUID
C#, SQL Server, and Windows docs usually write identifiers in uppercase with hyphens, e.g. 3F9A1C2E-8B4D-4E6A-9C1F-2A7B5D8E0F12. Copying production keys is risky.
ComTools GUID Generator (Tools/Developer/Guid) calls crypto.randomUUID() locally and uppercases the result. It is still UUID v4.
What a GUID looks like
36 characters including four hyphens; letters are uppercase:
XXXXXXXX-XXXX-4XXX-YXXX-XXXXXXXXXXXX
Example:
3F9A1C2E-8B4D-4E6A-9C1F-2A7B5D8E0F12
- Position 13 is version
4 - Variant bits follow RFC 4122
- Entropy comes from the browser’s secure random source
Steps
- Open GUID Generator.
- A value is generated on load; click Generate for a new one.
- Copy into C#, SQL, or config.
Nothing is uploaded.
vs the UUID tool
| Tool | Output |
|---|---|
| GUID Generator | Uppercase, e.g. A1B2C3D4-... |
| UUID Generator | Lowercase, e.g. a1b2c3d4-... |
Same algorithm, different case. JSON / Linux docs often use lowercase; .NET Guid and uniqueidentifier usually use uppercase.
Common scenarios
| Scenario | Tip |
|---|---|
C# Guid.NewGuid() samples |
Paste into docs or tests |
| SQL Server insert fixtures | '3F9A1C2E-...' or IN (N'...') |
| ID lists in long URLs | URL Params IN copy |
| Bulk fake rows | Fake data uuid column |
Notes
- Each click is a new random value.
- Needs
crypto.randomUUID(modern browsers). - A GUID is not a secret and is not time-ordered.
Related
FAQ
Same as UUID?
Yes—v4 random ids. This page only uppercases the output.
32 hex chars without hyphens?
Generate, then strip -; this page outputs the canonical form.
Many at once?
One per click—or use fake data.