Lead hash is the md5 encrypted value of lead’s email. To obtain the MD5 hash value of your lead’s email, you can use various MD5 generator tools available online. One such tool is located at MD5 Hash Generator. Simply input the email address of your lead into the tool, and it will generate the corresponding MD5 hash value, which is known as {lead_hash}
Then, you will need to send a GET request to read the specific lead to this API endpoint: https://api.mailbluster.com/api/leads/{lead_hash}
Check out this guide: https://app.mailbluster.com/api-doc/leads/read.
Please note: Some technical knowledge is required to implement this technique.