Click "Generate UUID" to start
UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information in distributed systems. It consists of 32 hexadecimal characters, typically displayed in an 8-4-4-4-12 format with hyphens separating the groups.
This tool supports two of the most commonly used UUID versions: UUID v4 is generated from random numbers and contains no identifiable information, offering the best privacy and making it the recommended version for most use cases. UUID v1 is based on a timestamp and MAC address, containing time information that can be reverse-engineered, so it is not recommended for privacy-sensitive scenarios.
• Database Primary Keys: Avoid ID conflicts in distributed systems without a central ID allocation service
• API Request Tracking: Assign a unique ID to each request for log tracing and debugging
• Session Management: Generate secure Session IDs or Token identifiers
• File Naming: Prevent filename collisions in multi-user upload scenarios
• Order/Transaction IDs: Generate unique business transaction numbers
This UUID generator is simple and intuitive. Here is a detailed guide:
Select Version: Choose your desired version from the "UUID Version" dropdown. We recommend "UUID v4 (Random)", the most commonly used and secure version, entirely based on random numbers with no trackable information. If you need an identifier with embedded timestamp information, choose "UUID v1 (Timestamp)", but note that it exposes the generation time.
Set Quantity: Enter the number of UUIDs you want to generate (1-100) in the "Quantity" field. If you only need one UUID, leave the default value of 1. The bulk generation feature is ideal when you need multiple unique identifiers at once, such as pre-allocating IDs before a batch data import.
Choose Format: Check "Remove hyphens" to convert the standard format (e.g., 550e8400-e29b-41d4-a716-446655440000) to a hyphen-free format (e.g., 550e8400e29b41d4a716446655440000). The hyphen-free format is easier to handle in some programming languages and databases, though less readable.
Generate & Export: Click the "Generate UUID" button to generate results. After generation, use "Copy All" to copy all UUIDs to your clipboard, or "Download" to save the results as a text file. Each UUID has an individual copy button on the right for quick single-copy access.
UUIDs are widely used in modern software development. Here are some typical scenarios:
Distributed Database Primary Keys: In microservice architectures, multiple services may write to the database simultaneously. Using UUIDs as primary keys ensures that IDs generated by different services never conflict, eliminating the need for a centralized ID allocation service like Snowflake. This is especially common in NoSQL databases like MongoDB and Cassandra, which natively recommend UUIDs as primary keys.
API Request Tracking and Distributed Tracing: In microservice architectures, a single request may pass through multiple services. Assigning a UUID as a Trace ID for each request allows you to trace the complete lifecycle of the request in your logs. When issues arise, the Trace ID helps quickly pinpoint the specific request chain and the processing time of each service, significantly improving troubleshooting efficiency.
Secure Token and Session Management: In user authentication systems, UUIDs are often used to generate Session IDs, Refresh Tokens, and API Keys. Due to the extreme randomness of UUID v4, they are theoretically impossible to guess or brute-force. Combined with appropriate expiration mechanisms and secure storage practices, they can form a robust user authentication system.
UUID Structure: A standard UUID consists of 128 bits, represented by 32 hexadecimal characters plus 4 hyphens in an 8-4-4-4-12 grouping. The 13th character identifies the UUID version (1 for v1, 4 for v4), and the first two bits of the 17th character identify the variant (typically 10 for RFC 4122). This structure allows UUIDs to be quickly identified and parsed.
UUID v7: UUID v7 is a new standard published in 2022 (RFC draft) that encodes a timestamp in the first 48 bits while keeping the remaining 80 bits random. This preserves the ability to sort by time while avoiding the privacy leakage of v1. v7 is considered the best future choice for UUIDs but has not yet been widely adopted.
UUID vs GUID: GUID (Globally Unique Identifier) is Microsoft's implementation of UUID. They are essentially the same. GUID is commonly used in the .NET ecosystem and Windows systems, while UUID is the term used in other languages and standards. The UUIDs generated by this tool fully comply with RFC 4122 and can be used in any system that supports UUIDs.
Collision Probability: UUID v4 has 2^122 possible combinations (approximately 5.3×10^36). Even generating one billion UUIDs per second, it would take about 85 years to reach a 50% probability of a single collision. In practice, this collision probability is negligible. However, if you require extreme uniqueness guarantees, consider using UUID v7 or combining with other strategies like timestamps.
UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information in distributed systems. UUID v4 is the most commonly used version, generated from random numbers with approximately 2^122 possible combinations, making collisions virtually impossible.
UUID v1 is based on a timestamp and MAC address, containing time information that can be reverse-engineered. UUID v4 is entirely random, containing no identifiable information and offering better privacy. UUID v4 is the recommended version for most use cases.
UUID v4 has an extremely small collision probability (about 1 in 2^122), which is practically negligible. Even generating a billion UUIDs per second, it would take approximately 85 years to reach a 50% chance of a single collision.
Not recommended. Although UUIDs have high randomness, they are designed for unique identification, not password security. Passwords should be generated by a dedicated password generator, creating high-entropy strings containing uppercase letters, lowercase letters, numbers, and special characters with sufficient length (at least 12 characters).
The hyphen-free format (32 characters) is easier to handle in some programming languages and databases. For example, it requires no additional encoding when passed in URL parameters, takes up less space in database indexes, and is more concise in code. However, it is less readable and harder to debug than the standard format.
Each has its pros and cons. Auto-increment IDs offer better query performance and smaller storage, but cannot be generated in a distributed manner and may expose data volume. UUIDs can be generated in a distributed way, do not expose data volume, and are more secure, but take up more space (16 bytes vs 4-8 bytes) and have slightly worse index performance. Choose based on your specific scenario, or consider a compromise like the Snowflake algorithm.
A valid UUID should comply with RFC 4122: 32 hexadecimal characters, with the 13th character as the version number (1, 4, 6, 7, etc.), and the first two bits of the 17th character as the variant identifier (typically 10). The standard format uses an 8-4-4-4-12 grouping. All UUIDs generated by this tool are strictly validated.
UUID v4 is entirely random and cannot be reverse-engineered to extract any information. UUID v1 contains timestamp and MAC address information, which could theoretically be reverse-engineered to reveal the generation time and device information. If privacy is a concern, always use UUID v4.