title: Can't upload file to S3 with Postman using pre-signed URL. Error: SignatureDoesNotMatch
body: <p>How do I upload a file to S3 with a signed URL?</p>
  
  <p>I tried the following:</p>
  
  <pre><code>  const AWS = require('aws-sdk');
    const s3 = new AWS.S3({ accessKeyId: "", secretAccessKey: "" });
  
    const url = s3.getSignedUrl("putObject", {
      Bucket: "SomeBucketHere",
      Key: "SomeNameHere",
      ContentType: "binary/octet-stream",
      Expires: 600
    });
  </code></pre>
  
  <p>But when I try uploading with Postman using the following steps, I get the <code>SignatureDoesNotMatch</code> error.</p>
  
  <ol>
  <li>PUT method with URL from the above code</li>
  <li>Body: <code>binary</code> (radio button), choose file, select a file to upload</li>
  <li>Hit Send</li>
  </ol>
  
  <p>I can confirm that the IAM permissions are not the problem here. I have complete access to the Bucket.</p>
  
  <p>What's wrong and how do I test my signed URL?</p>