Hey there! Should clarify. Atomic is non custodial wallet, your private keys are encrypted and never leave your device. Atomic is built on top of common open source libraries, like bitcoin core. However GUI is not open sourced. It's trusted by over 200K users all over the world. None of our users have ever been compromised, until they keep backup in a secure place! You can always check reviews on Trustpilot or Google play before using any app. Exchange feature is provided by our partner Changenow, they are looking for the best rates for you and use liquidity on major exchanges. Hope that makes sense! you are always welcome to give us a shot! https://atomicwallet.io/