An email finder software allows you to find the email of your prospect based on minimal informations such as first name, last name and/or company name.
Some softwares guess the right email address and other have large databases.
Most email finder softwares don't provide you with valid email addresses. They guess what could be the right email and give probabilities but there is still uncertainty. Some of these softwares are free but risky because if your emails bounce too much, your deliverablity will be affected. Beware of that.
Some email sofwtares focus on valid email addresses. Most of the time, they also provide much more data than the email istelf such as the linkedin URL of the lead or the website. Such platforms are called sales data intelligence softwares. Some of the tools in the space are UpLead, Apollo.io or Seamless.io.
We recommend to focus on email finder softwares whose priority is valid email address.
Don't waste your time and energy with softwares which will make false promises. The objective is to have emails that don't bounce.
Therefore we recommend: hunter.io as the reference or apollo.io even though some of their data is a bit off sometimes.
You can check manually if an email address is valid by putting it into gmail. By faking a send, you will see if gmail shows infos about your prospect like it does normally.