The most SF venture thing ever. Backing builders, hackers, founders, creators, and ideas that sound crazy until they work. 415 is the signal.
San Francisco, California
Joined March 2026
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Sf moves different.
We're thrilled to lead Mirendil's $200M seed round.
Frontier AI work has been locked inside a few big labs.
@mirendil is building a system that can help anyone do AI work: they train frontier models that are expert at AI R&D and build the product around it. The result is a system that loops over research and engineering problems on its own, making progress without human intervention.
It's like a coding agent built for AI research that controls its own GPUs.
Mirendil is one of the few teams with the experience and the priors to make the end-to-end system work. @bneyshabur, @HarshMeh1a, @shayan_, and @tararezaeikh come out of Anthropic, Google DeepMind, and xAI.
Welcome to the a16z family, Mirendil.
By @BornsteinMatt and @MaikaThoughts
sf is still the only place where someone can explain what they are building and it sounds completely insane for 10 minutes
then they show you the demo
and you realize they might actually be right
Putting together a small dinner in San Francisco.
Not for the most funded founders.
Not for the biggest accounts.
For the people building things that make you stop and think:
“Wait… that’s actually possible?”
Reply with a demo, screenshot, photo, prototype, customer message, or anything interesting.
A few of my favorites are joining me for dinner.
SF founders, this is the bat signal.
If you are building something in San Francisco that feels too early, too weird, too technical, too niche, or too ambitious for most people to understand yet, drop it below.
No polished launch needed.
No perfect deck needed.
No “warm intro” needed.
Just tell us:
What are you building?
Why now?
Why you?
We are turning 415 Venture into the front door for SF builders.
Founders, reply below.
Investors, scout the replies.
Operators, find your next thing.
And if you are raising, DM us the deck.
Let’s see what SF is actually building.
Just secured 415venture.com + @415venture at 11pm on a Friday.
415 is a magical number if you’re from San Francisco.
So I’m doing the most SF thing ever:
Starting a venture thing before fully knowing what it becomes.
No fund yet. No Sand Hill office. Just belief that SF still has the best builders, AI founders, startup talent, operators, creators, hackers, angels, and weird late night ideas on earth.
I want 415 Venture to become a hub for SF founders, investors, builders, creators, and anyone working on something that sounds crazy until it works.
Maybe it becomes a fund. Maybe a syndicate. Maybe founder dinners, angel checks, intros, content, events, and a group chat that gets out of hand.
DM me if you’re building, investing, connecting, or want to help make this real.
415 Venture starts tonight.
Let’s make SF loud again.