Bring the writing room to your Mac.

Installing

1. Download the app. Click the button above to get Proselon.dmg.
2. Open the disk image and drag Proselon into your Applications folder.
3. Open it and create your account. The app is signed and notarized by Apple, so it opens like any Mac app. On first launch, create your Proselon account: an email and a password, made right in the app. Your free 30-day trial starts here.
4. Sign into your AI. Choose your writing engine and sign in the way you always do — Claude, for example, with your regular account, no API keys necessary — or a free local model you run yourself. The app walks you through it. Then open your first book and start writing.

Proselon is free for 30 days, then $6 a month or $50 a year — and we always email you before we charge you. Cancel in one click any time, and anyone who asks gets a refund. The co-writer itself works with your own AI account — Claude, ChatGPT, or Grok, signed in the way you always do — a Gemini API key if you choose Gemini, or a free local model through Ollama or LM Studio. No API keys or metered usage from us. Your books are plain files in Documents › Proselon, and your manuscript stays on your Mac. The app signs into your account and checks for updates, but your book is never uploaded to us.