<!-- Do not edit this file. It is automatically generated by API Documenter. --> [Home](./index.md) > [puppeteer](./puppeteer.md) > [SecurityDetails](./puppeteer.securitydetails.md) > [validFrom](./puppeteer.securitydetails.validfrom.md) ## SecurityDetails.validFrom() method <b>Signature:</b> ```typescript validFrom(): number; ``` <b>Returns:</b> number [Unix timestamp](https://en.wikipedia.org/wiki/Unix_time) marking the start of the certificate's validity.