You can make requests to the Veracode service by sending an HMAC signature in the HTTP authorization header.
The mechanism is discussed on "Understanding API Access" https://help.veracode.com/reader/lsoDk5r2cv~YrwLQSI7lfw/H0S3580tt9sPFz3IgSMvnA with a Java program as illustration. For an API wrapper in GO, see https://github.com/brian1917/vcodeHMAC.
For illustration and plain shell scripting on the command line, it's possible to compute the Authorization header using openssl. Here's how: