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 articlesAI Gateway Guide: What They Are, Why You Need One, and How to Choose
A comprehensive guide to AI gateways — the proxy layer between your app and LLM providers. Compare Cloudflare AI Gateway, Portkey, Helicone, LiteLLM, AWS Bedrock, Azure APIM, and more across pricing, features, and architecture.
Read article →Developer Experience Compared: Cloudflare vs AWS vs Azure vs Google Cloud
A technical comparison of developer experience across Cloudflare, AWS, Azure, and Google Cloud — CLI tools, local development, deployment speed, documentation, IaC support, console UX, and the day-to-day reality of building on each platform.
Read article →Cloud Provider Comparison: Cloudflare vs AWS vs Azure vs Google Cloud — The Complete Guide
The definitive guide to comparing Cloudflare, AWS, Azure, and Google Cloud across 13 service categories — CDN, storage, DNS, serverless, security, databases, pricing, developer experience, and more. Understand each provider's architecture philosophy and make informed decisions.
Read article →Gemini CLI vs Claude Code vs Codex: Choosing the Right AI Coding CLI
Compare the three major AI coding CLI tools - Gemini CLI, Claude Code, and OpenAI Codex CLI. Understand context windows, pricing, features, and when to use each for maximum productivity.
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 →