Developer & data utilities
UUID Generator
Generate random UUID v4 identifiers in bulk with copy-to-clipboard.
Run UUID Generator online
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The UUID Generator creates cryptographically random Version 4 UUIDs (Universally Unique Identifiers) — 128-bit identifiers represented as 32 hexadecimal digits in the format 8-4-4-4-12. UUIDs are the standard way to generate unique keys for database records, API resources, session tokens, file names, and any system requiring collision-free identification without central coordination.
UUID v4 uses the browser's built-in `crypto.randomUUID()` (or falls back to Math.random()) to generate identifiers with 122 random bits. The probability of generating two identical UUIDs across all systems is astronomically small — approximately 1 in 5.3 × 10³⁶ for any two specific UUIDs. This makes them safe to use as primary keys without checking for existing values.
Common use cases in software development: database primary keys (instead of auto-increment integers, which reveal row count), S3 object names, Stripe payment IDs, tracking pixels, distributed system request IDs, and idempotency keys in payment APIs. You can generate up to 100 UUIDs at once and copy them all with one click for bulk insertion in databases or config files.
How to use this utility
- Use the controls below—paste text, pick files, or adjust options as described on the tool.
- Click the main action button. Processing runs in your browser on this device.
- Download or copy the output. Check the processing note for any external services used by this operation.
Common use cases
- Generating primary keys for PostgreSQL, MySQL, or MongoDB documents
- Creating unique file names for uploaded content in AWS S3 or GCS
- Generating idempotency keys for payment API requests
- Creating unique session identifiers for web application users
- Generating test data with unique IDs for development environments
Tips for best results
- 1Use UUIDs for public-facing IDs (API resources) to prevent enumeration attacks
- 2Store UUIDs as binary(16) in MySQL rather than varchar(36) for 2× space efficiency
- 3UUID v7 (time-ordered) is better than v4 for database indexing — use if your DB supports it
- 4Do not use UUIDs where sequential ordering matters — prefer ULID or KSUID instead
- 5Lowercase UUIDs are conventional; uppercase is valid but less common
Frequently asked questions
- Is Konnect2Tools free?
- Yes. These in-browser tools are completely free to use with no account required for core functionality.
- Do my files leave my device?
- Browser document operations run locally, except where the operation uses an external service, such as AI summarisation. Read the processing note before using sensitive inputs.
- Is the UUID Generator tool safe to use?
- Local operations process document content on your device. External-service operations may send inputs as described in the processing note. Keep originals and inspect the output.
- What is the difference between UUID v1, v4, and v7?
- UUID v1 is timestamp + MAC address — leaks system info, avoid. UUID v4 is purely random — safe and widely used. UUID v7 is timestamp-ordered random — better for database indexes as it avoids page splits. For most uses, v4 is the right choice; use v7 if you care about DB performance.
- Can two generated UUIDs ever be the same?
- Theoretically possible but practically impossible. The probability of any two UUID v4 being identical is ~1 in 5.3 × 10³⁶. To have a 50% chance of a collision, you would need to generate 2.7 × 10¹⁸ UUIDs. This exceeds the number of grains of sand on Earth.
- Should I use UUID or auto-increment for database primary keys?
- UUIDs: better for distributed systems, no enumeration risk, can be generated client-side. Auto-increment: simpler, smaller (4–8 bytes vs 16), better for join performance, reveals record count. For user-facing APIs, use UUID (or hash the int). For internal tables, auto-increment is fine.
- Is this UUID generator cryptographically secure?
- We use the browser's built-in crypto.randomUUID() when available, which is cryptographically secure. The fallback uses Math.random() which is not cryptographically secure. In modern browsers (Chrome, Firefox, Edge, Safari), crypto.randomUUID() is always available.
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