Loyal AI
PRIVATE PERSONAL AI
The most
loyal AI
Your own AI for email, calendar, meeting notes, dictation and errands. He runs on your computer, so nothing leaves the house.
Apple devicesWindowsLinux and Android are on the wayLinux & Android soon
Invite-only beta. Getting better every day.
Doctor’s appointments, prescription refills, tax paperwork. I find what you need and get the next step ready for your approval.
I’m very good at fetch. Woof.
Sensitive tasks. Protected. Doctor’s appointments, prescription refills, tax paperwork. I find what you need and get the next step ready for your approval.
WALL OF LOVE
What people are saying
Ben Horowitz@bhorowitzI always love the underdog
Dane Knecht@dok2001Been waiting for something like this and it is better than advertised. Congrats @0xSigil . First AI agent I was actually willing to test because I like to keep my data local.
D.A. Wallach@dawallachPlaying with @underdogai and it is the right approach. @0xSigil nice work!
Vishal Talasani@shellvishUnderdog is the best consumer AI experience I've had since ChatGPT
Thomas Wolf@Thom_Wolfseems obvious that most personal AI should run on your device love what Sigil is building with Underdog - powered by the Hugging Face hub
Mario Gabriele@mariogabrielespeed of iteration of sigil and underdog is pretty remarkable...shipping improvements on ~hourly cadence
Alex Yao@TheAlexYaoJust unsubscribed from Granola & Wisprflow after onboarding to Underdog 🐶
Underdog AI @UnderdogAIToday we’re releasing Underdog Bark 3.0, the #1 frontier speech model It's a tiny 163 MB download as accurate as NVIDIA’s Parakeet (15x bigger). It beats OpenAI's Whisper large-v3 (57x bigger)
Naval Ravikant@navalIncredible name 👌.
alby13@alby13Underdog Saluki 27B has been downloaded 500k times.
Marco Mascorro@MascobotI’ve been using @underdogai and it’s pretty neat. It runs all locally and it’s the best private/personal AI I’ve tested with my email.
Julian Schiavo@_julianschiavoAlso, Sigil’s speed is just ridiculous. He’s been fixing my toothing issues all day and all night. Insane dedication
Guillermo Rauch@rauchgHappy underdog user. Every human and every company must own their intelligence stack
Dan Von Kohorn@danvkI love using @UnderdogAI for email. 🔥 All my accounts in one place, understanding my contacts and preferences, nicely connected to my calendar and meeting notes, and wrapped in a private chat and private context that never leaves my mac. This is the future! 🚀🐶
Varun Srinivasan@varunsrinunderdog has a 10/10 consumer onboarding experience and the fastest setup path to a getting a local model very exciting to see local ai get easier to use!
Ivan Fioravanti@ivanfioravantiI love the Unsubscribe newsletters feature of @UnderdogAI 🔥 I cleaned a lot of them! You can even search for specific ones! Like I did for shopping! I've used the new model Saluki 27B 2bit here.
Ben Horowitz@bhorowitzI always love the underdog
Guillermo Rauch@rauchgHappy underdog user. Every human and every company must own their intelligence stack
Dane Knecht@dok2001Been waiting for something like this and it is better than advertised. Congrats @0xSigil . First AI agent I was actually willing to test because I like to keep my data local.
Underdog AI @UnderdogAIToday we’re releasing Underdog Bark 3.0, the #1 frontier speech model It's a tiny 163 MB download as accurate as NVIDIA’s Parakeet (15x bigger). It beats OpenAI's Whisper large-v3 (57x bigger)
Naval Ravikant@navalIncredible name 👌.
Dan Von Kohorn@danvkI love using @UnderdogAI for email. 🔥 All my accounts in one place, understanding my contacts and preferences, nicely connected to my calendar and meeting notes, and wrapped in a private chat and private context that never leaves my mac. This is the future! 🚀🐶
D.A. Wallach@dawallachPlaying with @underdogai and it is the right approach. @0xSigil nice work!
Varun Srinivasan@varunsrinunderdog has a 10/10 consumer onboarding experience and the fastest setup path to a getting a local model very exciting to see local ai get easier to use!
Vishal Talasani@shellvishUnderdog is the best consumer AI experience I've had since ChatGPT
alby13@alby13Underdog Saluki 27B has been downloaded 500k times.
Thomas Wolf@Thom_Wolfseems obvious that most personal AI should run on your device love what Sigil is building with Underdog - powered by the Hugging Face hub
Marco Mascorro@MascobotI’ve been using @underdogai and it’s pretty neat. It runs all locally and it’s the best private/personal AI I’ve tested with my email.
Ivan Fioravanti@ivanfioravantiI love the Unsubscribe newsletters feature of @UnderdogAI 🔥 I cleaned a lot of them! You can even search for specific ones! Like I did for shopping! I've used the new model Saluki 27B 2bit here.
Mario Gabriele@mariogabrielespeed of iteration of sigil and underdog is pretty remarkable...shipping improvements on ~hourly cadence
Julian Schiavo@_julianschiavoAlso, Sigil’s speed is just ridiculous. He’s been fixing my toothing issues all day and all night. Insane dedication
Alex Yao@TheAlexYaoJust unsubscribed from Granola & Wisprflow after onboarding to Underdog 🐶
MODELS
I’m Saluki 27B. Meet my brothers.
on your
Poodle 4B The fast one.
115tokens a second
Saluki 27B The smart one.
33.7vs 31.9 for Claude Opus 4.6 Max
Chihuahua 2B The light one.
Faston your phone
Speeds are estimates. Scores are from the Artificial Analysis Intelligence Index.
LOYAL MEANS LOYAL
Aligned with you.
Not advertisers. Not an AI lab. You.
100% local intelligence
Summaries, drafts, and answers come from a model running on your computer.
Mail goes straight to your provider
Mail syncs directly between your computer and your email provider.
Memory you can inspect
Saved memories stay on your computer. See, edit, or delete them in Settings.
Guards the door
Keeps you safe from remote images, scripts, and tracking pixels. Stripped on sight.
Protected where he sleeps
Every account gets its own vault. The key is locked away on your computer and never leaves it.
Naval mode
One switch, and Loyal never calls home.
WHO HAS CHECKED
Top hackers keep Loyal safe.
Bringing me to work? Send your security team our security page.
- PassedLeviathan Security GroupThe App Defense Alliance assessment. All 20 requirements pass.
- ApprovedGoogleApproved Loyal to read your Gmail and Calendar.
- CompletedHacktron AI, the team that hacked OpenAIFinished a penetration test of the Mac app.
- Completed
Finished a penetration test of the Mac app, underdog.ai and Dogpark. - Under way
Auditing Loyal now. - Under wayJane Manchun WongTaking the Mac app apart to look for holes.
THE MANIFESTO
Most AI will run in data centers. on your device.
“Own your AI, don’t let it own you. I’m building Underdog for myself.”
THE TEAM
A tiny but mighty team of underdogs.
We come from Apple, Ramp, Google Brain, Meta, MrBeast, Baidu, Lyft, Instagram, the United Nations and the Thiel Fellowship.
Backed by
- Andreessen Horowitz
- Khosla Ventures
- Hummingbird
- Anthologyfund in partnership with Anthropic
- SV Angel
- Breakneck
And angels including Patrick Collison (Stripe), Naval Ravikant, Guillermo Rauch (Vercel) and Noam Brown (OpenAI). We raised this first round in April 2026. See all our backers →
BEFORE YOU BRING ME HOME
All questions answered.
It’s free? What’s the catch?
Loyal saves you time and money. When you ask him to buy something, he finds the cheapest, best option (saving you hundreds to thousands of dollars) and pays with a one-time card made just for that order, and we make a tiny bit of it. Your mail, calendar, notes, and AI stay free.
Which AI does Loyal use?
Our own, and they run on your computer. Woof 4B is small but mighty and fast. His big brother, Underdog 27B, beats Claude Opus 4.6 Max on the Artificial Analysis index. Either way, your content isn’t sent to a cloud AI service.
How does my email sync?
Mail syncs directly between your computer and your email provider. Your AI processing happens privately on your computer.
What stays on my device?
AI processing happens on your computer, where Loyal stores your recordings, notes, and transcripts. Mail syncs directly with your email provider. Messages you send and bookings you approve go to their intended recipients or websites.
Can I use Loyal at work?
Yes. Send your security team our security page. It says who has checked Loyal, what the app connects to, and what it keeps on your computer.
What does Loyal need to run?
A Mac with Apple silicon, or a Windows PC in our beta. iPhone and iPad are coming soon to the App Store. Android and Linux are coming too — tick the ones you want and we’ll send one email per build when it ships.
When can I adopt him?
Today, with an invite and a Mac with Apple silicon. Windows is in beta. Adopt Loyal. No invite yet? Leave your email there and we’ll save your spot in line. iPhone and iPad are coming soon to the App Store. For every other device, pick yours below and we will send one email when that build is ready — nothing more.
GOOD DAYS START WITH A GOOD DOG
Bring me home.
Fast email. Calendar. Meeting notes. Dictation. Your own AI, 100% private, on your computer.
Waiting for another device?
iPhone, iPad, Windows, Android, and Linux. Pick your devices and hear when I’m ready.