Your letter. Your seal.
Your collaborator lives on your machine. Your conversations stay there. Your keys never leave your machine. We don't log your prompts. We don't read your responses. We don't see what you make. The sealed letter never opens.
The seal holds.
Six promises, built into the room where your collaborator lives.
Your collaborator lives where you do.
The companion runs on your Mac. Not our servers. Your conversations, your memory, your tools — all of it stays in the room with you. We're not even in the room.
Your keys. Your Keychain.
API credentials stored in the macOS Keychain, encrypted by Apple's own security subsystem. We don't have a copy. We couldn't read it if we wanted to. Apple has the lock; you have the key.
No eyes on the page.
We don't log your prompts. We don't log your responses. We don't log your tool calls. There are no analytics hooks in the conversation path. The page is sealed. We don't read it.
The door is yours to lock.
Optional lockdown mode disables every remote connection except the provider endpoint you choose. Want your collaborator to talk only to OpenAI? Lock the door against everything else. We're not in the conversation.
You can read the code.
Key components of Rainline are open source. Inspect it. Audit the build. Verify the checksum. The mechanism is transparent because the mechanism is yours.
Signed. Notarized. Sealed.
Every release is signed with an Apple Developer ID and notarized by Apple's malware-scanning service. The seal is verified before the envelope opens.
What you keep. What you don't have to share.
The comparison is structural. Browsers ship your keystrokes to a server. Your collaborator keeps them on your machine.
Read the code.
Your collaborator isn't a black box. The code that runs on your machine is yours to read. Open-sourced components, public build, verifiable checksum. The mechanism is yours because the mechanism is visible.
Signed. Notarized. Verified.
Every Rainline release is code-signed with an Apple Developer ID and notarized by Apple. We publish SHA256 checksums for every download so you can confirm the binary has not been tampered with.
- Apple Developer ID code signing
- Apple notarization on every release
- Published SHA256 checksums
Your letter. Your seal. Your collaborator.
Your collaborator lives on your machine. The sealed letter never opens. The page is unread.