Written in 2023, 3 years ago. Tools and advice may have moved on since.
Use GATSBY_ for environmental variables (env vars) you use in your client-side code. In practice, that would be almost all of your code. The exceptions are code inside gatsby-node.js, gatsby-config.js, and a page’s getServerData or config.
Exposing all env vars on the client would be a major security hazard. We use env vars for things such as API secrets, etc.
XATA_API_KEY=xau_werIJslsdf8wekfsflr06ZxzyYYVpsMF6
GATSBY_RECAPTCHA_SITE_KEY=6LeIxAcTAAAAAJcZVRqyHh71UMIEGNQ_MXjiZKhI
All the best,
Queen Raae