I’ve built a backend application using Node.js, Express, and MongoDB, and I’m attempting to deploy it on AWS using the Serverless Framework. The application works perfectly in my local environment, but when I deploy it to AWS and try to call the API using Postman, I receive a 500 Internal Server Error.

Setup Details:
• Framework: Serverless Framework
• Environment: AWS Lambda (Node.js runtime)
• API Structure:
• Using Express as the web framework
• Routes include /api/v1/users/login, /api/v1/videos, etc.
• CORS enabled
• Error handling implemented

Error Encountered:
When I send a request to my API endpoint, I receive the following response:

{ "message": "Internal Server Error" }

Code Snippet:

Here’s my src/index.js:

import dotenv from "dotenv";
import connectDB from "./db/index.js";
import { app } from "./app.js";
import serverless from "serverless-http";

dotenv.config({
  path: "./.env",
});

connectDB()
  .then(() => {
    app.on("error", (error) => {
      console.log("ERROR: ", error);
      throw error;
    });

    app.listen(process.env.PORT || 8000, () => {
      console.log(`Server is running at port: ${process.env.PORT}`);
    });
  })
  .catch((error) => {
    console.log("MONGODB connection failed !!! ", error);
  });

export const handler = serverless(app);

Here’s my src/app.js:

import express from "express";
import cors from "cors";
import cookieParser from "cookie-parser";

const app = express();

app.use(
  cors({
    origin: process.env.CORS_ORIGIN,
    credentials: true,
  })
);
// setting for handling json
app.use(
  express.json({
    limit: "16kb",
  })
);
//setting for URLS
app.use(
  express.urlencoded({
    extended: true,
    limit: "16kb",
  })
);
app.use(express.static("public"));
//config cookie-parse
app.use(cookieParser());

// routes import
import userRouter from "./routes/users.routes.js";
import videoRouter from "./routes/video.routes.js";
import commentRouter from "./routes/comment.routes.js";
import likeRouter from "./routes/like.routes.js";
import tweetRouter from "./routes/tweet.routes.js";
import subscriptionRouter from "./routes/subscription.routes.js";
import playlistRouter from "./routes/playlist.routes.js";
import dashboardRouter from "./routes/dashboard.routes.js";
import { ApiError } from "./utils/ApiError.js";

//routes declaration
app.use("/api/v1/users", userRouter);
app.use("/api/v1/videos", videoRouter);
app.use("/api/v1/comments", commentRouter);
app.use("/api/v1/likes", likeRouter);
app.use("/api/v1/tweets", tweetRouter);
app.use("/api/v1/subscription", subscriptionRouter);
app.use("/api/v1/dashboard", dashboardRouter);
app.use("/api/v1/playlist", playlistRouter);

app.use((err, req, res, next) => {
  if (err instanceof ApiError) {
    // Send a JSON response with the error details
    return res.status(err.statusCode).json({
      success: err.success,
      message: err.message,
      errors: err.errors,
    });
  }

  // For other errors, send a generic 500 response
  // res.status(500).json({
  //   success: false,
  //   message: "An unexpected error occurred.",
  // });
});

export { app };

Here’s my serverless.yml:

service: playtube-api

provider:
  name: aws
  runtime: nodejs20.x
  region: ap-south-1
  environment:
    PORT: ${env:PORT}
    CORS_ORIGIN: ${env:CORS_ORIGIN}
    MONGODB_URI: ${env:MONGODB_URI}
    ACCESS_TOKEN_SECRET: ${env:ACCESS_TOKEN_SECRET}
    ACCESS_TOKEN_EXPIRY: ${env:ACCESS_TOKEN_EXPIRY}
    REFRESH_TOKEN_SECRET: ${env:REFRESH_TOKEN_SECRET}
    REFRESH_TOKEN_EXPIRY: ${env:REFRESH_TOKEN_EXPIRY}
    CLOUDINARY_CLOUD_NAME: ${env:CLOUDINARY_CLOUD_NAME}
    CLOUDINARY_API_KEY: ${env:CLOUDINARY_API_KEY}
    CLOUDINARY_API_SECRET: ${env:CLOUDINARY_API_SECRET}
    CLOUDINARY_URL: ${env:CLOUDINARY_URL}

functions:
  api:
    handler: src/index.handler
    events:
      - httpApi:
          path: /{proxy+}
          method: ANY

plugins:
  - serverless-dotenv-plugin

It’s my first time using it and deploying backend server kindly help me, I would be grateful.