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Local IntelliSense Kit

A Docker Compose setup for the IntelliSense gateway — real completions, hovers and diagnostics for Python, C/C++, Rust, Go and Java — pre-configured to work with this site's Run Settings.

New here?

This is an optional, advanced download for people who already have a challenge or two under their belt and want more control over their setup. If you're brand new here, you don't need this yet — see New to Coding? Start Here instead.

.zip · Docker Compose + IntelliSense source

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Why would I want this?

By default, IntelliSense talks to a gateway we host. Running your own copy locally is useful if you're offline or just want to see how it works under the hood. Nothing about using the site normally requires this — it's entirely optional. ("Run Code" always uses our hosted compiler — this download doesn't include a code runner; see the note below for why.)

Setup

  1. Make sure Docker is installed and running.
  2. Download the zip above and unzip it anywhere on your computer.
  3. Open a terminal (on Windows, this is Command Prompt or PowerShell; on Mac, it's the Terminal app) in that folder and run docker compose up -d --build. The first run takes a few minutes — it's installing a JDK, Go, clangd, and a few other language servers.
  4. On the site, click the gear icon (Run Settings) in the navbar, turn on Local IntelliSense, and use Test connection — it should say "Connected".
This used to also include a self-hosted Judge0 (the code runner), removed because Judge0's sandboxing needs the legacy cgroup v1 hierarchy, which Windows/WSL2 no longer supports at all as of WSL version 2.5.1 — so it simply can't run under Docker on Windows anymore. "Run Code" always uses our hosted Judge0 now; that has nothing to do with IntelliSense, which works fine locally regardless. The zip includes a full README.md with the details plus troubleshooting steps for IntelliSense itself.