5.5. github.dev vs. Codespaces
Both open in a browser and look similar at a glance — but one of them can actually run your code, and the exam wants you to know which.
💡 First Principle: github.dev is a lightweight, client-side code editor with no compute behind it — press . on any GitHub repository page and it opens instantly, letting you browse and edit files with a real editor's ergonomics. What it can't do is run code, open a terminal, or install dependencies, because there's no machine behind it — it's editing, not execution. Codespaces is the opposite trade-off: slower to start because it provisions a real cloud machine, but capable of running, testing, and debugging the project like a full local environment.
| github.dev | Codespaces | |
|---|---|---|
| Compute behind it? | No | Yes, a real cloud VM |
| Can run code? | No | Yes |
| Has a terminal? | No | Yes |
| Startup time | Instant | Seconds to a couple minutes |
| Best for | Quick edits, browsing | Actually running/testing a project |
⚠️ Exam Trap: github.dev cannot execute code or open a terminal — it's an editor only. Any scenario that mentions running, testing, or debugging code in the browser is describing Codespaces, not github.dev.
Reflection Question: Someone wants to quickly fix a typo in a config file without leaving their browser or waiting for anything to provision. Which tool fits, and why is the other one unnecessary here?
