AWS S3 Error 403: Access Denied in Node.js

1. ERROR DETAILS

Error code: 403 Forbidden AWS service: Amazon S3 Node.js SDK: AWS SDK for JavaScript v3 Typical exception: S3ServiceException: Access Denied

HTTP 403 occurs when Amazon S3 denies a request because the effective permissions of the calling identity do not authorize the requested operation.

2. IMMEDIATE FIX

Step 1: Apply least-privilege IAM permissions

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "ListApplicationPrefix",
      "Effect": "Allow",
      "Action": "s3:ListBucket",
      "Resource": "arn:aws:s3:::YOUR_BUCKET_NAME"
    },
    {
      "Sid": "ReadApplicationObjects",
      "Effect": "Allow",
      "Action": "s3:GetObject",
      "Resource": "arn:aws:s3:::YOUR_BUCKET_NAME/app/*"
    }
  ]
}

Step 2: Configure the Node.js AWS SDK v3 client

const { S3Client, GetObjectCommand } = require("@aws-sdk/client-s3");
const s3 = new S3Client({ region: process.env.AWS_REGION });