Tools · 4 min read

How to use the Code Execution API in Python & JavaScript

Some features aren't worth building from scratch. The Code Execution API is one endpoint that replaces a lot of plumbing.

By DataNest · Published May 2026

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What the Code Execution API does

Execute code in 45+ languages inside a secure sandbox. Returns stdout, stderr, compile output, timing, and memory — the engine behind coding platforms. Responses are JSON, the API runs behind the RapidAPI gateway for auth and rate limiting, and there's a free tier for prototyping.

When to use it

online coding platforms

technical interviews

e-learning playgrounds

The example request

POST https://code-execution-by-datanest.p.rapidapi.com/submissions

Example JSON response

An illustrative response body — run the live demo for the real thing.

{
  "stdout": "5050\n",
  "stderr": null,
  "compileOutput": null,
  "status": {
    "id": 3,
    "description": "Accepted"
  },
  "time": "0.012",
  "memory": 3456
}

Common parameters

Every request also needs your RapidAPI auth headers.

Parameter	In	Required	Example
base64_encoded	query	No	false
wait	query	No	true
source_code	body	Yes	print(sum(range(1,101)))
language_id	body	Yes	71
x-rapidapi-key	header	Yes	YOUR_RAPIDAPI_KEY
x-rapidapi-host	header	Yes	code-execution-by-datanest.p.rapidapi.com

Step by step

1. Subscribe and get your key

Open the Code Execution API on RapidAPI, subscribe to the free BASIC plan, and copy your X-RapidAPI-Key.

2. Call the endpoint

The example call for this API is shown above. The quick-start snippets below send exactly that request in cURL, Python and Node so you get a real response on the first try.

3. Try it without code first

The Code Execution page has a live "Try it" panel — change the input, run it, and inspect the real JSON before you integrate.

4. Integrate and cache

Call it from your backend and cache responses where it makes sense. Most responses change slowly, so even a daily cache keeps you well within the free tier.

Quick-start code

curl --request POST \
  --url 'https://code-execution-by-datanest.p.rapidapi.com/submissions?base64_encoded=false&wait=true' \
  --header 'x-rapidapi-host: code-execution-by-datanest.p.rapidapi.com' \
  --header 'x-rapidapi-key: YOUR_RAPIDAPI_KEY'

What you can build

Coding playground

Run user-submitted snippets in 45+ languages without your own sandbox.

Interview platform

Execute candidate solutions against test cases in real time.

E-learning runner

Let students run lesson code in the browser with full output.

Wrapping up

If your project needs online coding platforms, the Code Execution API removes the part nobody enjoys building. It's one of 23 in the DataNest collection — grab a free key and make your first call.

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Code Execution updates

New Code Execution guides and endpoint updates, occasionally.