How do you store and manage your API keys?

I don't mean for each individual app and how they access them, but rather if and how you manage all of them in one place.

Do you use a password manager like 1Password to keep track of them?

Many API keys you could just retrieve from the associated site when you need them. But some of them only show you the API key once upon creation.

I have used 1Password for years and it's great. I'll store api keys, etc in Secure Notes and mostly on the servers via .env files or environment variables.

Lastpass is also awesome if you're not always on Apple devices

Keepassxc on Linux, KeePassDroid on my Pixel2, db file sync'd via Dropbox. If you're talking about on your app or code, then each situation is different but it's normal to have environment variables store that or special configs that are only stored in the environments that need to use them.

I use KeyPassX and Cryptomator, synced over Dropbox, across several devices.