How to Use UUID Bulk Generator, Step by Step
Reviewed by the OnlineFree.app team · Updated
Key points
- UUID Bulk Generator creates up to 1,000 RFC-compliant v4 or v7 UUIDs per click, entirely in the browser with no signup.
- Every generated value is 36 characters: 32 hex digits with hyphens after positions 8, 12, 16 and 20.
- Choose v7 over v4 when IDs go into an indexed column, because its 48-bit timestamp prefix keeps inserts ordered.
- The uppercase toggle produces GUID-style output for systems that expect capital letters; normalise case before string comparisons.
- A UUID is an identifier, not a secret — do not reuse these values as API keys or password-reset tokens.
What does UUID Bulk Generator actually do?
UUID Bulk Generator produces a batch of RFC-compliant universally unique identifiers — v4 random or v7 time-ordered — inside your browser tab, one per line, ready to copy. You pick a version, pick a count, optionally switch to uppercase, press Generate, and the whole list lands in a monospace textarea with no signup and no round-trip to a server.
Every identifier is 36 characters: 32 hexadecimal digits grouped by hyphens after the 8th, 12th, 16th and 20th characters. A v4 value follows the original RFC 4122 layout, while v7 follows the newer RFC 9562 specification, which formalised time-ordered UUIDs in 2024.
The randomness comes from `crypto.getRandomValues`, the browser's cryptographically secure generator, not `Math.random`. Because the whole loop runs client-side, the tool behaves the same on a locked-down corporate laptop as on a phone — and the page auto-generates 10 v4 UUIDs on first load, so you never stare at an empty panel while deciding what to do.
Step by step: a batch in under ten seconds
Open UUID Bulk Generator and you already have a usable batch: the default state is 10 UUIDs in v4. If that suits you, click Copy all and paste. Most people are done in two clicks.
To change it: pick v4 or v7 from the version dropdown, type a number between 1 and 1,000 in the count field, and hit Generate — or just press Enter while the cursor is still in the count box. Flip the uppercase toggle if a downstream system expects GUID-style output like `A1B2C3D4-E5F6-...`, which some Microsoft tooling and older SQL Server schemas do.
The result panel header shows what you asked for, e.g. "10 × UUID v4" plus the total count, so you can confirm the batch size before pasting. The textarea is selectable and editable — if one stray line bothers you, delete it by hand before copying. Copy all places the entire list on the clipboard as newline-separated text and flashes a confirmation such as "Copied 100 UUIDs"; if the browser denies clipboard access, the tool falls back to selecting the text so you can press Ctrl+C yourself.
One habit worth forming: leave the textarea untouched until you have copied. Regenerating replaces the batch, and there is no undo.
v4 or v7: which version should you choose?
Start with v4 for anything client-facing, and switch to v7 when the IDs are landing in an indexed database column. A v4 UUID is essentially 122 random bits, so it reveals nothing about when or where it was created — useful for public URLs, invite codes and anything a user might eyeball.
A v7 UUID puts a 48-bit Unix millisecond timestamp in the front, which makes values sort roughly in creation order. In PostgreSQL, MySQL or SQLite, that keeps inserts near the end of a B-tree index instead of scattering them across pages the way random v4 keys do. Our implementation also carries a monotonic counter so that several IDs generated within the same millisecond still sort in the order they were produced.
The trade-off is that v7 leaks creation time to anyone holding the string. If that matters — think customer-facing identifiers where signup date is sensitive — stay on v4. If you need true chronological sorting with no timestamp exposure, you need a separate `created_at` column, not a different UUID version.
How many UUIDs can you generate at once?
The count field accepts between 1 and 1,000 per batch; anything empty, non-numeric or out of range is clamped or falls back to 10. A thousand IDs is roughly 37 KB of text and 1,000 lines, which pastes cleanly into a spreadsheet column, a `seed.sql` file or a `INSERT ... VALUES` block.
At that size, duplicates are not a practical concern. With 122 random bits in v4, the chance of even one collision inside a 1,000-row batch sits around 1 in 10²⁶ — you are far more likely to mistype the table name in your migration.
Need more than 1,000? Generate two or three batches and concatenate them; the same logic applies, and mismatched case between batches is the only thing to watch for. If you are seeding a table of 50,000 rows, generating 50 batches by hand gets tedious — that is the point where a short script calling the same browser crypto API is the better tool, and we say so plainly.
Small limits and common mistakes
Two mistakes account for most of the support questions we see. The first is pasting uppercase GUIDs into a system that stores lowercase and then comparing strings with `=`. Normalise case before you compare or index — a column-level cast in Postgres (`::uuid`) handles it, but a plain text column will not.
The second is treating a UUID as a secret. A v4 value has plenty of entropy, but it is displayed on screen and copied to your clipboard, which makes it unsuitable as a password, API key or password-reset token. Use a dedicated secret generator for those and let UUIDs do their actual job: stable identifiers.
A few practical notes. Store IDs in a native `uuid` type where the database has one rather than a 36-character string, and validate anything arriving from a client before it reaches a query. If you are debugging v7 values and want to know when one was minted, the leading 48 bits are a Unix millisecond timestamp — paste the value into a decoder or convert the extracted millisecond figure with the Timezone Converter to read it in local time. And if you need other quick utilities alongside this one, OnlineFree.app keeps them in the same no-signup, browser-only style.
Frequently asked questions
Is UUID Bulk Generator free, and do I need an account?
Yes, it is free and needs no account, email or sign-in. Open the page and it has already generated 10 v4 UUIDs for you. The tool runs entirely in the browser tab, so there is no trial limit, no watermark and no per-batch quota other than the 1,000-per-click count cap.
Do the UUIDs I generate leave my device?
No. UUID Bulk Generator builds every identifier locally with the browser's crypto.getRandomValues API and never sends the batch to a server. Nothing is logged or stored between visits, so closing the tab discards the list. The only copy that persists is the one you paste or place on your clipboard.
What is the difference between v4 and v7 in UUID Bulk Generator?
v4 is 122 random bits and reveals nothing about creation time. v7 prefixes a 48-bit Unix millisecond timestamp and adds a monotonic counter, so values sort in creation order — better for indexed database inserts. Choose v4 for public-facing IDs where creation time should stay private, and v7 for ordered keys.
Can I generate more than 1,000 UUIDs in one batch?
No, the count field is clamped to a maximum of 1,000 per click. For larger sets, generate several batches and join them, or write a short script using the same crypto API. At 1,000 IDs per batch, duplicate risk remains negligible because v4 carries 122 random bits.
Are the generated UUIDs safe to use as API keys or passwords?
No, we do not recommend it. UUIDs are designed as identifiers, not secrets: they are shown on screen, copied to a shared clipboard and often logged in URLs. Use a dedicated cryptographic secret generator for API keys, session tokens and password-reset links, and reserve UUIDs for database keys and fixtures.