[Home](./index.md) > [puppeteer](./puppeteer.md) > [SecurityDetails](./puppeteer.securitydetails.md) > [validFrom](./puppeteer.securitydetails.validfrom.md) ## SecurityDetails.validFrom() method Signature: ```typescript validFrom(): number; ``` Returns: number [Unix timestamp](https://en.wikipedia.org/wiki/Unix_time) marking the start of the certificate's validity.