Code Execution API & Terminal
Backend and compiled language apps run on the cdbx Code Execution API — a server-side execution service that streams output back to your browser in real time.
How it works
When you click Run, cdbx sends your code to the Code Execution API, which executes it inside an isolated container and streams stdout and stderr back line by line. The output appears in the Terminal panel on the right side of the editor.
There is no build step — the Code Execution API compiles and executes your code directly.
Supported languages
30 languages, all running the same way — isolated container, no network, streamed output:
Python, Go, JavaScript (Node 20), TypeScript (Bun), Rust, C#, Java, Kotlin, Ruby, C, C++, PHP, Perl, Lua, R, Swift, Scala, Haskell, Elixir, Clojure, Bash, D, Nim, Zig, OCaml, F#, Julia, Dart, Crystal, Groovy.
Execution limits
| Limit | Value |
|---|---|
| Timeout | 30 seconds |
| Output | Streamed line by line |
| Network | Disabled inside containers |
| File system | Isolated per run |
Each run starts in a clean container — no state carries over between runs.
Terminal output
The terminal panel shows:
- stdout — everything your program prints
- stderr — error output, shown in red
- Exit code — displayed when execution completes (
exit 0= success, non-zero = error) - Elapsed time — shown next to the exit code
The Run button shows a spinner while execution is in progress. Click it again to cancel a running job.
Multi-file programs
The Code Execution API receives all files in your app. Your entry file (e.g. main.py, main.go) is the execution target. You can split code across multiple files and import them normally — it writes all files to the container before executing.
AI assistance
The AI chat is aware you're working in a backend context. It will write code for your language, read your files, and fix errors surfaced in the terminal. Use the Fix error button that appears when a run fails to send the error directly to the AI.