My App Platform deploy succeeds but the app keeps crashing / health checks fail

Hey all,

I pushed my Node/Express app to App Platform from GitHub. The build succeeds, but then the deployment fails and the logs just show it restarting over and over. Sometimes I see “readiness probe failed” or the deploy times out.

It runs perfectly on my laptop. What am I doing wrong?

Here’s how I start my server:

    const express = require("express");
    const app = express();

    app.get("/", (req, res) => res.send("Hello"));

    app.listen(3000, "localhost", () => {
        console.log("Server running on http://localhost:3000");
    });