UUID Generator — Examples

Back to overview: UUID Generator · Open the live tool: www.jpkc.com/tools/uuid/

This page shows the UUID Generator through concrete walkthroughs. The UUID values shown are examples — yours will differ every time (except for v5 and NIL). Exactly how each version works is covered in the manual.

Example 1: Generate a single v4 UUID

Goal: quickly get a random identifier for a new record.

1. The v4 Random tab is already active on load.
2. Leave Number of UUIDs at 1.
3. Click Generate UUID(s) v4.

Result: the result field shows a random UUID such as f47ac10b-58cc-4372-a567-0e02b2c3d479. The clipboard button copies it. Click Generate again and you get a completely different UUID — v4 is purely random.

Example 2: 100 v7 UUIDs for a migration

Goal: generate a batch of time-sortable keys at once, for instance to give existing records new primary keys.

1. Open the v7 Time-ordered tab.
2. Set Number of UUIDs to 100.
3. Click Generate UUID(s) v7.

Result: the field fills with 100 UUIDs, one per line. Because v7 carries a leading timestamp, the values all start similarly and rise slightly — they are roughly ordered by creation time. The copy button grabs the whole block to paste into, say, a SQL script or a CSV. This sortability makes v7 nicer for database indexes than random v4 (see tips).

Example 3: A v1 UUID without a MAC address

Goal: produce a classic time-based identifier and confirm no hardware identifier is in it.

1. Open the v1 Time-based tab.
2. Leave Number of UUIDs at 1.
3. Click Generate UUID(s) v1.

Result: you get a v1 UUID. The timestamp part sits at the front, while the trailing node part is generated randomly here — so the tool does not expose your MAC address, unlike some classic v1 implementations. For new projects v7 is usually still the better time-based choice; v1 is mainly useful when an existing system requires it.

Example 4: A deterministic v5 UUID from a domain

Goal: derive a stable, reproducible identifier from a domain name.

1. Open the v5 Name-based tab.
2. Set Namespace to DNS (the default).
3. In Name, enter example.com.
4. Click Generate UUID v5.

Result: you always get the same UUID — for example.com in the DNS namespace that is cfbff0d1-9375-5685-968c-48ce8b15ae17. Generate it tomorrow or on another machine and you get exactly the same value. That is the whole point of v5: a reliable key you can recompute from the same name at any time, without having to store it.

Example 5: v5 with a custom namespace

Goal: derive UUIDs in a project-specific namespace, separate from the standard ones.

1. On the v5 Name-based tab, set Namespace to Custom UUID — the Custom Namespace UUID field becomes active.
2. Enter a valid namespace UUID there, e.g. one previously generated with v4: f47ac10b-58cc-4372-a567-0e02b2c3d479.
3. In Name, enter the value to derive, such as user:42.
4. Click Generate UUID v5.

Result: you get a v5 UUID specific to your project: the same name user:42 yields a different UUID in your custom namespace than in the DNS namespace. If you mistype the namespace UUID (wrong length or invalid characters), the tool rejects it with "Invalid namespace UUID format." — the input must match the 8-4-4-4-12 format exactly.

Example 6: Copy the NIL UUID

Goal: quickly grab the null placeholder 00000000-0000-0000-0000-000000000000.

1. The NIL UUID sits permanently in the card footer.
2. Click the small copy button right beside it.

Result: the NIL UUID is on the clipboard. It is handy when a schema requires a UUID but you deliberately want to express "none yet" — for instance as a default value or a placeholder in tests. It is not "generated"; it is always the same constant.

---

More on each version and option is in the manual, strategy and pitfalls in the tips & tricks. Jump straight in with the tool.