require() of a package that is ES modules only

What it means

The code loads with require() a package that only ships ES modules (node-fetch 3, chalk 5, nanoid 4 and others).

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

Install the previous CommonJS major (node-fetch@2, chalk@4), switch the code to import with "type": "module" in package.json, or pick Node.js 22 in the settings, which can require ES modules.

1. 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. 2 After the fix, deploy again. If it fails again, the log ends with [mevcore] lines naming the new error code.
3. 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.esm_require
phase: start / health check
diagnosis: require() of a package that is ES modules only
platform hint: The code loads with require() a package that only ships ES modules (node-fetch 3, chalk 5, nanoid 4 and others). Install the previous CommonJS major (node-fetch@2, chalk@4), switch the code to import with "type": "module" in package.json, or pick Node.js 22 in the settings, which can require ES modules.
platform docs: https://mevcore.com/llms-full.txt

Related errors

• runtime.esm_import_statement import in a file Node.js reads as CommonJS
• runtime.esm_missing_extension ES module import without a file extension: <module>