Can I use a custom startup command to control the Node.js/runtime version?

Sometimes a library needs a specific runtime version — maybe an older Node.js line for compatibility. Your server's Settings page (the old Startup page) gives you control over this. This article explains what you can adjust and what to do for edge cases.

Controlling your runtime version

You can set the runtime version and startup options on the Settings page, which covers most version needs. For example, if a dependency only works on an older Node.js line, you can select that version so your bot runs cleanly.

When a version isn't selectable

Some eggs have the Docker image locked by us for stability, which means a specific version might not be selectable on the Settings page. If you need a version that isn't available in the dropdown:

1. Check the Settings page first to see whether the version you need is already selectable.
2. If it isn't, open a ticket describing the version you need and why.
3. We'll help get you onto a compatible runtime.

Tip: Most compatibility problems are solved just by switching the runtime line on the Settings page — try that before assuming you need a locked image changed.

Frequently asked questions

Why are some Docker images locked? We lock certain images for stability so servers stay reliable. When a locked image blocks a version you genuinely need, open a ticket and we'll sort it out.

Can I set custom startup flags? Yes — the Settings page exposes startup options alongside the version, so you can tune how your runtime launches.