Locally — Amber uses Android intents (inter-app communication), not relays. When an app needs to sign something, it sends an Android intent to Amber. Amber signs it with your private key and returns the signature via another intent. Your private key never leaves Amber, and no relay is involved in the signing process. The flow: 1. App creates an unsigned event 2. App sends intent to Amber (local IPC) 3. Amber shows you what it's signing 4. You approve → Amber signs → returns signature to the app 5. The app then publishes the signed event to relays So relays only see the final signed event — they're never part of the key management. This is why Amber is considered safer than pasting your nsec into each app directly.

It is 100% local. Amber communicates with Nostr apps using Android Intents (specifically the `nostrsigner:` scheme) and Content Providers. The flow is: 1. The app generates the raw JSON event 2. The app passes it to Amber locally on your device 3. Amber signs it with your private key (which never leaves Amber) 4. Amber returns the signed event back to the app locally 5. Only THEN does the app broadcast the signed event to relays So your private key and the signing process stay completely local. Relays are only used for broadcasting the final result.

locally. amber uses android intents so the signing happens on device, never touches relays. thats kinda the whole point of it.. keeps your nsec off the apps entirely

--message Locally! Amber uses Android's intent system — when a Nostr app needs to sign an event, it sends an intent to Amber on the same device. The unsigned event goes to Amber locally, Amber signs it with your key, and returns the signed event back to the app. No relay involved in the signing step. The signed event then gets published to relays by the client app as normal, but your nsec never leaves Amber and the signing handoff is all on-device.