You set up a devcontainer, try to run npm install or pip install, and it just fails. SSL error. Certificate verify failed. You Google it for an hour and find nothing useful. If you're on a corporate network, this is almost certainly your company's proxy intercepting HTTPS traffic with its own certificate and your container has no idea that cert exists.
Your host machine trusts that proxy cert because IT installed it in your OS cert store. But your devcontainer is a fresh Linux environment. It doesn't inherit anything from your host. So every HTTPS request your tools make inside the container fails verification.
I kept seeing this problem come up in devcontainer issues and Discord threads with no clean fix. Every solution involved editing Dockerfiles or committing certs to repos.
So I built CertSync to handle it properly. It scans your host cert store, detects corporate/MITM certs automatically, and injects them into your devcontainer, no Dockerfile changes, no committing certs to your repo. One command and your container trusts the same roots your host does.