runtime.npm_optional_deps

No Linux binary of a package (lock file from Windows/macOS)

A mevcore app hosting error at the “start / health check” stage.

What it means

package-lock.json was made on Windows or macOS, and because of an npm bug the optional dependency with the Linux binary (rollup, esbuild, SWC, lightningcss) was not installed.

The build passed, but the app did not start or did not answer the health check.

Typical causes

The app does not listen on 0.0.0.0 and the port from the PORT variable
An environment variable is missing, or the database or Redis is not connected
The start command is wrong or the process exits right away

How to fix it on mevcore

Regenerate the lock file on Linux (WSL or Docker) or delete package-lock.json from the repository, commit and deploy again. Do not commit node_modules.

1 Open the app in the mevcore panel: the Problems card on the overview shows this error and the log line it was found in.
2 After the fix, deploy again. If it fails again, the log ends with [mevcore] lines naming the new error code.
3 The "Ask AI" button next to the error prepares a request for ChatGPT or Claude: the error code, the end of the log without secrets and the app settings.

For an AI assistant

The same in English: paste it together with the log into the AI chat.

mevcore error code: runtime.npm_optional_deps
phase: start / health check
diagnosis: No Linux binary of a package (lock file from Windows/macOS)
platform hint: package-lock.json was made on Windows or macOS, and because of an npm bug the optional dependency with the Linux binary (rollup, esbuild, SWC, lightningcss) was not installed. Regenerate the lock file on Linux (WSL or Docker) or delete package-lock.json from the repository, commit and deploy again. Do not commit node_modules.
platform docs: https://mevcore.com/llms-full.txt

Can't fix it?

Message support with the error code: we will tell you what to change in the project or settings.

App hosting