UUIDs provide collision-resistant identifiers for distributed systems.
UUID versions
- v1: Timestamp-based (reveals MAC address and creation time).
- v4: Random (most common, cryptographically random).
- v5: Name-based with SHA-1 hashing (deterministic).
- v7: New timestamp-based with improved sorting (RFC draft).
Format
- 8-4-4-4-12 hexadecimal digits: 550e8400-e29b-41d4-a716-446655440000.
Use cases
- Database primary keys in distributed systems.
- Session identifiers and API tokens.
- File and document naming.
- Correlation IDs in microservices.
Security considerations
- UUIDv1 leaks MAC address and timestamp.
- Prefer UUIDv4 for security-sensitive applications.
- Not suitable as secrets or passwords.
Related Articles
View all articlesHow to Use Claude Code From Your Phone With /remote-control
Claude Code's Remote Control feature lets you steer a coding session running on your machine from your phone, tablet, or browser. Here's how to set it up, when it beats Claude Code on the web, and the security model behind it.
Read article →How to Recover an Accidentally Closed Claude Code Session
Closed your Claude Code terminal by accident? Your conversation isn't gone. Learn how to resume it with claude --continue and --resume, where transcripts are stored on disk, and how to reopen the closed terminal window itself on macOS and Windows.
Read article →Gemini CLI Is Being Retired on June 18 — Meet Antigravity CLI
Google is deprecating Gemini CLI and moving developers to the new Antigravity CLI on June 18, 2026. Here's what's actually changing, who's affected, the CI/CD landmine to watch for, and how to migrate before your scripts break.
Read article →Claude Code's Security-Guidance Plugin: Shift-Left Security That Fixes Code as You Write It
Anthropic's free security-guidance plugin makes Claude Code review and fix vulnerabilities in the same session. Here's what it catches, how to install it, and how to roll org-wide rules across your team.
Read article →Explore More Development
View all termsAPI (Application Programming Interface)
A set of rules and protocols that allows different software applications to communicate and exchange data.
Read more →Cron Expression
A time-based job scheduling syntax using five or six fields to specify when tasks should run.
Read more →DevOps
A set of practices combining software development (Dev) and IT operations (Ops) to shorten development cycles and deliver high-quality software continuously.
Read more →Diff Algorithm
A computational method for comparing two sets of data and identifying differences between them.
Read more →GitOps
An operational framework that uses Git repositories as the single source of truth for declarative infrastructure and application configurations.
Read more →JSON (JavaScript Object Notation)
A lightweight data interchange format using human-readable text to represent structured data.
Read more →