UUID Studio

UUID Studio

MongoDB UUID Converter

Decode and encode MongoDB Extended JSON UUID blobs.

  • đź”’ No data stored or uploaded
  • ⚡ 100% client-side
  • 🆓 Free, no account
Click Convert when ready

Override only when Auto cannot parse your paste. Changing this loads a matching sample into Input — click Convert to run. Use Load sample to cycle every format example.

All conversions

Read-only representations of the same 16 bytes. Every textual form is listed here, not in “Prefer format”.

Paste two values: if both sides are valid JSON, a structural diff appears; otherwise UUID / bytes are compared when both decode to the same format.

A
B

Create or edit JSON here (syntax colors), then format, validate, or convert - same as MongoDB $binary UUID blobs on the Convert tab once detected.

New document

Hash, HMAC, AES-GCM/CBC + RSA-OAEP, codecs, JWT decoding, UUID v4, and secure random - all client-side. JWTs use Base64URL (three segments), not a single MIME Base64 block - use Decode JWT below, not raw Base64 decode.

Examples

  • Subtype 04 (RFC 4122) 
    { "$binary": { "base64": "VQ6EAOKbQdSnFkRmVUQAAA==", "subType": "04" } }
  • Plain GUID after export 
    550e8400-e29b-41d4-a716-446655440000

About MongoDB UUID Converter

MongoDB has quietly used two different byte layouts for UUIDs over the years - legacy subtype 0x03 from early C# drivers, and RFC 4122-compliant subtype 0x04 used everywhere since. Compass and most modern drivers surface both as Extended JSON with a $binary wrapper, which is unreadable at a glance.

Paste that Extended JSON (or a plain decoded GUID) and this tool decodes it back to a standard UUID string, plus re-encodes it into BSON-friendly forms - handy when you're migrating data between subtype 3 and subtype 4, or just trying to figure out why a UUID column looks scrambled in one driver and normal in another.

If you only have a bare Base64 string without the $binary wrapper, use the main UUID Converter with 'Prefer format' set to Mongo instead.

FAQ

What is subtype 03 vs 04?
Subtype 04 follows RFC 4122 byte layout. Subtype 03 is the legacy C# driver layout - decoding may differ from standard GUID strings.
Can I paste only Base64?
Use the main UUID converter with Prefer format set to Mongo, or paste the full $binary object for automatic detection.