zippydevtoolsGenerators
UUID v4 Generator
Generate up to 20 UUID v4 values for test fixtures and mock data, then copy them as lines, a JSON array, or a CSV column.
Process the input to see the result here.
Generate UUID v4 batches for fixtures, tests, and prototypes with copy-ready lines, a JSON array, or a one-column CSV.
When to use
Use it when you need independent random identifiers for mocks, seed data, temporary records, or distributed components.
Input
Enter a quantity from 1 to 20 and choose lines, JSON, or CSV to match the target fixture.
Output
Copy preserves the selected output: plain lines, a valid JSON array, or a single-column CSV with a uuid header.
- Choose from 1 to 20 UUIDs for the batch.
- Select lines, JSON array, or CSV for the target file.
- Generate, review the structure, and copy without losing the selected formatting.
- Enforce uniqueness in the system and do not use UUID v4 as a secret or sortable ID.
- Test fixtures: Create independent IDs for examples, mocks, and temporary data during development.
- Database prototypes: Generate identifiers for prototypes, seeds, or manual records in non-critical environments.
- Distributed systems: Use UUID v4 when separate parts need IDs with a very low practical collision chance.
- Not absolute uniqueness: The collision chance is extremely low, but not mathematically impossible.
- Random source: The tool uses crypto.randomUUID when available and a v4-compatible fallback otherwise.
- Batch limit: The 20-ID limit keeps output readable and easy to copy.
- Not authentication: UUIDs do not replace tokens, passwords, secret keys, or authorization controls.
- UUID v4 Generator for Fixtures: Formats and Limits
Generate UUID v4 fixture IDs in lines, JSON, or CSV and understand collision risk, database ordering, secrets, and browser-local processing.
Line-separated fixture IDs
Input: Quantity: 3; format: one UUID per line
Output: Three UUID v4 values on separate copy-ready lines.
JSON array for tests
Input: Quantity: 5; format: JSON array
Output: A valid JSON array containing five UUID v4 values.
CSV column for seed data
Input: Quantity: 4; format: CSV with header
Output: A uuid column followed by four data rows.
How do I generate UUIDs for fixtures and tests?
Choose a quantity from 1 to 20, select lines, JSON, or CSV, and run the generator. Copy preserves the exact displayed format.
Why is each batch limited to 20 UUIDs?
The limit keeps manual batches readable, quick to review, and easy to copy. Generate larger volumes in project code or at the database layer.
Which output format should I choose?
Use lines for individual IDs, JSON for test arrays and fixtures, or CSV for a single uuid column with a header.
Does it use browser crypto APIs?
When available, the tool uses crypto.randomUUID(). Browsers without that method use a fallback compatible with UUID v4 format.
Does UUID v4 guarantee that collisions never happen?
No identifier offers an absolute guarantee here. The random space makes collisions extremely unlikely for common batches, but critical systems should still enforce uniqueness.
Can UUID v4 replace a password, token, or sortable ID?
No. UUID v4 is a random identifier, not a secret, and it does not preserve time order. Use purpose-built authentication or sortable-ID mechanisms.
Are generated UUIDs sent to a backend?
No. Generation, formatting, and copying run in the browser without sending UUID values to the tool backend.