Pattern-based email guessing is the technique of constructing a person's likely email address by applying a company's known email format to that person's name. Most companies use one consistent pattern — such as `firstname.lastname@company.com`, `firstname@company.com`, or `flastname@company.com` — across all employees.
The method works in two steps: first, determine the company's pattern by finding one known employee email (from a tool, a public source, or a GitHub commit); second, apply that pattern to the name of the person you want to reach. This is the core mechanic behind most email-finding tools and the backbone of outbound research.
Because guesses can be wrong — people with hyphenated names, duplicates, or unusual setups break the pattern — pattern-based guessing must always be paired with email verification. Verifying before sending prevents bounces that would otherwise harm your sender reputation.