The SMTP Field Manual is a new resource launched by Wildbit, an email service provider with nearly 16 years of experience. The manual aims to bring clarity and accuracy to SMTP response codes, which are often confusing and vary widely across different inbox providers. By documenting these responses, the manual seeks to help customer support teams, email server administrators, and email deliverability teams better understand what each code means and how to address issues. The resource is designed to be a one-stop solution for understanding all major SMTP error codes, with updates contributed from the industry, making it an essential tool for anyone involved in email delivery.