Simple rule
Use UTC for logs, APIs, databases, and cross-region operations.
UTC and GMT are close enough for many casual conversations, but they are not the same thing in practice. If you work in ops, product, or engineering, UTC is usually the better label.
Think about it this way: GMT is tied to a timezone idea. UTC is the cleaner technical standard for systems, logs, and global coordination.
| Term | Meaning | When it applies |
|---|---|---|
| UTC | Coordinated Universal Time | Technical systems, timestamps, APIs, global ops |
| GMT | Greenwich Mean Time | UK winter time and casual time references |
| Better default | UTC | When you want one standard for software and distributed teams |
Use UTC for logs, APIs, databases, and cross-region operations.
Use GMT mainly when you are actually describing UK winter time or speaking casually.
If a process is global, UTC is the cleaner shared language.