FAQ

Yes. TLD is completely free — no subscription, no credit card, no account required to run labs. The CLI, all labs, and all validators are open source under the Apache 2.0 license.

No. All labs run locally using Docker. You don't need an AWS, GCP, or Azure account. Everything runs on your machine.

Yes, via WSL2 (Windows Subsystem for Linux). You'll need Docker Desktop with WSL2 integration enabled. We recommend Ubuntu 22.04 as your WSL distro. Native Windows support without WSL is not planned.

Yes. Install Docker Desktop for Mac and the TLD CLI. Both Intel and Apple Silicon (M1/M2/M3) Macs are supported.

If you're signed in with a TLD account, your progress syncs automatically. If you run labs offline or without an account, progress is stored locally only.

TLD runs entirely on your own machine with real Docker containers — not simulated browser environments. This means real debugging, real tools, and real networking. Katacoda was shut down. KodeKloud uses simulated environments and requires a paid subscription for most content.

You need: Docker 24+, Node.js 18+ (for the npm install method), 4GB RAM minimum (8GB recommended), and 10GB free disk space for Docker images. Linux, macOS, and Windows (WSL2) are all supported.

Each lab includes a validator.sh — a bash script that checks whether your solution meets the lab's requirements. The script exits 0 on success and non-zero on failure. Running tld check executes this script inside the lab environment and reports results to you.

Yes. The validator source is visible — all labs are open source. But if you just engineer around the validator without understanding why your fix works, you're only cheating yourself. The validator checks outcomes, not methods.

Go produces small, fast, statically-linked binaries with no runtime dependencies. This makes distribution simple — a single binary works on Linux, macOS, and Windows without needing Node.js, Python, or any runtime installed. It also gives us strong cross-platform support with minimal complexity.

tld doctor checks your local environment for common issues: Docker running status, Docker version compatibility, network connectivity, available disk space, and CLI version. It's the first command to run when something isn't working.

Absolutely. Labs are just a README.md (instructions) and a validator.sh (checker) inside the challenges/ directory. See the Contributing section for the lab format and naming conventions.

No. Some of the best labs come from people who just learned a topic and documented their struggle. If you found something confusing and figured it out, write a lab about it.

Open a GitHub issue with the lab ID, your OS, Docker version, and the exact output you received. Include what you expected to happen and what happened instead.