# How to protect my license key **URL:** \ **Category:** Technical Support\ **Created:** [March 3, 2021, 9:30pm UTC](https://pdfjs.community/t/how-to-protect-my-license-key/560 "2021-03-03T21:30:42Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![stefans](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@stefans](https://pdfjs.community/u/stefans)\ **Post date:** [March 3, 2021, 9:30pm UTC](https://pdfjs.community/t/how-to-protect-my-license-key/560/1 "2021-03-03T21:30:42Z")
Hello, We are using PDF JS Express with React JS (front end). When we add PDF JS Express license key and API license key same as PDF JS Express documentation’s telling as we have security problem. When we’re using browser Dev Tools are licenses are visible. If I move my license in .env file I have watermark over my PDF document. How to add the license without worrying that my license might be stolen? Thank you, Stefan ---
**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\ **Post date:** [March 3, 2021, 9:43pm UTC](https://pdfjs.community/t/how-to-protect-my-license-key/560/2 "2021-03-03T21:43:33Z")
Hi, The license keys are tied to your domain and will only work on your domain, so you do not need to worry about it getting stolen. Thanks! ---
**Author:** ![stefans](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@stefans](https://pdfjs.community/u/stefans)\ **Post date:** [March 3, 2021, 9:45pm UTC](https://pdfjs.community/t/how-to-protect-my-license-key/560/3 "2021-03-03T21:45:51Z")
Perfect, thank you Logan! ---
**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\ **Post date:** [March 4, 2021, 3:16pm UTC](https://pdfjs.community/t/how-to-protect-my-license-key/560/4 "2021-03-04T15:16:48Z")