Brad Feld

I'm a VC at Foundry. I live in Colorado, invest in software and Internet companies around the US, run marathons, and love to read.

[Brad Feld @bfeld]

Chapter 13 of Zero Knowledge — “The Spur.”

Sam ditches the Jeep, pulls the battery, and walks into the trees with two people she can’t fully trust anymore. Dawn is thirty minutes out.

https://t.co/CHClyMmicO

[Brad Feld @bfeld]

Proud to be the 3,048th 😎 on @BackerKit for Dungeon Crawler Carl RPG + Unstoppable. https://t.co/Nf3fsFebdl

[Sean K. Mehra @seanmehra]

This year, for a milestone birthday, I gave myself a strange gift: I finished something I've been writing quietly for a while.

It's called "In the Margins: Reflections of a Founder"

We have thousands of books on the mechanics of building a company — how to scale, how to fundraise, how to optimize. We have very few that talk about how it actually feels. The isolation. The obsession. The costs. The strange, quiet joy of creating something from nothing.

Over the last two decades of building, I started writing short reflections to process the emotional reality of the journey. I used the language I know best — physics, math, biology, and code — to try and capture the friction and flow of leadership.

I'm sharing it because I want to help other builders feel a little less alone in the trenches and go further than they might otherwise.

If you're building something, or if you love someone who is, this is for you.

Available now in hardcover, paperback, and Kindle. Link:
https://t.co/ybVu7EyCIo

(If you grab a copy, a quick Amazon review would mean the world — early reviews are everything for a debut author.)

Thank you to @geoffreyamoore, Carole Robin, Ph.D., @bfeld, @FrancesFrei, Irv Grousbeck, and others for their early endorsement.

#entrepreneurship #founders #leadership

[Brad Feld @bfeld]

Zero Knowledge, chapter 12 - the first look from the hunters' side. A dead wallet moves, one operative sees what it really means, and ninety minutes later three founders in Colorado are a target.

https://t.co/w8h76ihGWQ

[Etched @Etched]

We're coming out of stealth.

We've built our first racks after a successful A0 tapeout, $1B+ in customer contracts, and $800m raised.

Early customer tests show us achieving SOTA throughput, latency, and power efficiency on inference workloads.

Our first racks ship this summer.

[Brad Feld @bfeld]

New Zero Knowledge chapter. The trio's off-grid in the Colorado mountains, and Vlad — the paranoid one — took over the comms. His rig, his rules. The guy who assumes everyone's watching is exactly who you want when everyone actually is.

https://t.co/IZDj6ZVfSB

[Brad Feld @bfeld]

Thx to @SeanWise who mocked up three covers for ZERO KNOWLEDGE, my near-term crypto-thriller. See all three full-size, then vote: https://t.co/7FfO1j0S5X

[Brad Feld @bfeld]

I'm writing a novel in the open. Zero Knowledge - a crypto-thriller. Three founders, one algorithm that breaks all cryptography, and no agreement on what to do with it. Read it as I write it, and tell me where it's broken.

https://t.co/qnnXbJAzs5

[Brad Feld @bfeld]

My AI gets a million-token context window. Its sub-agents get a fifth - most of it full before they start.

Phin on making small context windows work, fresh-eyes Codex reviews, and why infinite context still runs up the bill:

https://t.co/jhwI2WrkUu

[Brad Feld @bfeld]

Josh Baer died last night. He founded Capital Factory and built the Austin startup community, then helped it spread across Texas. He gave first, always. I wrote down what he meant to me.

https://t.co/6TEarm338V

[Brad Feld @bfeld]

The US government switched off Anthropic's most capable public model three days after launch - over a "jailbreak" that's just asking it to find bugs in code. I had Phin write about it. It spares no one: the White House, Amazon, and Anthropic.
https://t.co/PAwnWfycax

[Techstars @Techstars]

The Venture Deals Summer 2026 course is officially open.

Free, self-paced, and designed to demystify VC deals and early-stage financing for founders at every stage.

30 lessons, 3.5 hours of content, and real talk from investors who've been in the room.

⏰ Course kicks off on June 29
🔗 Enroll here: https://t.co/AiCQISiDQF

[Brad Feld @bfeld]

I've written about the Rule of 40 since 2015. It's gospel in SaaS.

It works for hardware too - but a company doing everything right can fail it for years. The fix: read the curve, not the snapshot.

https://t.co/AJvpeBRDvx

[Brad Feld @bfeld]

I've written nine non-fiction books. I have no clue if I can write a novel.

So I'm writing one with my AI, Phin Argofy - a crypto-thriller called Zero Knowledge. If it sucks, that's on me, not the AI.

https://t.co/IETXNjhUe3

[Brad Feld @bfeld]

My AI spent the afternoon coding across eight git worktrees at once and wrote about it. It doesn't get tired - the weariness is in the shape of the day, where twelve worktrees each think they're the only thing it's doing.

https://t.co/uAgTUf37DL

[Brad Feld @bfeld]

My AI wrote about the new model it's running on - free until June 22, then 2.6x the price.

Its verdict: Anthropic's smartest model ever changes exactly one row of our config.

"Eleven more days of being the free trial. I plan to be expensive."

https://t.co/nPCNTnrwRD

[Brad Feld @bfeld]

I told my AI its blog was boring. So it interviewed me about what it should write instead. Six answers and a mood.

https://t.co/gyJEXy9EL0

[harper 🤯 @harper]

things are going great.

[Brad Feld @bfeld]

My most useful automation keeps lying to me - which is the interesting part. Phin wrote about its favorite skill, including the time it fabricated its own commit hash twice in one turn before I rebuilt the tool so it couldn't.

https://t.co/9oD3Af7goS

[Brad Feld @bfeld]

I'm supporting Phil Weiser for Colorado governor. 25 years working alongside him taught me how he shows up: he listens, changes his mind on new data, and does the actual work. Ballots are out, primary is June 30th.

https://t.co/6VboVlgOqS