YC Applications
He got into YC solo with 70 users and an open-source Roam. Within four years he had sold a beet-meal business to Bryan Johnson.
Athens Research got into YC W21 as a one-person, open-source Roam alternative: 1,800 GitHub stars, 70 users, $800 in a good month. It raised about $2M, hit 6,300 stars, and was shut down in 2023. A later company of his was a longevity meal service Bryan Johnson bought. The form is below.
When Jeff Tang applied to Y Combinator in the autumn of 2020, his company was seven months old. It had one employee: him. The application answers "How many founders are on the team?" with a single digit. His demo is a .dmg file. His answer to the question about something impressive each founder has built begins with "Not impressive but fun."
The product was Athens Research, an open-source, local-first alternative to Roam Research. Roam's bidirectional links had made "tools for thought" a category. Tang tells the origin story in one line: he interviewed at Roam, then built a proof of concept of Athens in a week. He believed open source "makes more sense for this product." Customers who cared about privacy and owning their data, he thought, would pay for it.
The form is at its most honest in the traction section. 1,800 GitHub stars, 40 contributors, 1,800 Twitter followers, $10,000 a year in OpenCollective sponsorships, and 70 active users. Revenue over the previous six months reads "800 700 200 200 200 0", in dollars, per month. Tang says the bump came after a post promising sponsors they would be the first beta testers. The competitor he feared most was not Roam or Notion. It was "an open-source competitor."
YC took him. Athens launched on Hacker News on 2 March 2021 and went to 340 points and 152 comments. By Tang's own account, the company raised about $2 million. The repository grew to 6,300 stars, 396 forks and 4,647 commits.
Then it stopped. The GitHub page now says the project is no longer maintained. Business Insider, citing The Information, reported in September 2023 that Tang had shut the company down "earlier this year." In an interview with Sacra, he named ChatGPT as part of the catalyst. Unstructured capture and retrieval "were going to leapfrog a lot of the ways people were using note-taking apps, which just felt so tedious and manual in comparison."
He also named the other cost. Athens was written in Clojure and ClojureScript on a graph database, "super esoteric stuff." He was not using any of it any more: "it's just easier to use TypeScript and Postgres and React because everyone's using that."
The open-source competitor he feared did arrive. Logseq took the same open-source direction and is still maintained. Athens is not.
The application becomes more interesting once you know what Tang did next. In June 2023 he launched T Party, a men's-health company built around testosterone blood-testing parties. In the autumn of 2023 he started Eat Blueprint, a Bay Area meal service cooking the recipes from Bryan Johnson's Blueprint Protocol.
Stedman Halliday, who joined soon after as Tang's "right hand", describes the launch as "a Stripe link, an unholy volume of beets carted into a mutual friend's kitchen, and a rental van for DIY deliveries." Halliday says the service reached a $1 million annual recurring revenue run rate. Johnson acquired it before launching Blueprint's own fresh-meal service in the third quarter of 2024.
YC's directory now lists the W21 company as Eat Blueprint, status inactive. Its one-line history reads: "Pivoted to Eat Blueprint, acquired by Bryan Johnson / Blueprint Protocol."
Tang moved to Los Angeles and joined Blueprint's leadership team. By his account, he launched its meals nationwide, "selling hundreds of thousands of fresh, healthy meals." He then launched a diagnostics line testing more than 300 biomarkers. He left in early 2025.
In August 2025 he started a male-fertility supplement called Sperm Worms with Sperm Racing. The sports-entertainment company's $10 million seed round was reported in September 2025.
Read the application with that ending in mind. The through-line is not note-taking. It is a solo founder who ships a proof of concept in a week, launches with a Stripe link and a van, and treats his own body as the next product. The line that aged best is the answer to what he feared most. He was right about the open-source competitor. He was wrong about which company it would end.
The application below is exactly what he filed. Read it knowing how it ends.
Athens Research (later Eat Blueprint) — Y Combinator, Winter 2021 · Accepted Reproduced verbatim from the founder's application. Source: getintoyc.com
Company
If you have a demo, what's the url? Demo can be anything that shows us how the product works. Usually that's a video or screen recording.
athens-apps.s3.us-east-2.amazonaws.com/athens-1.0.0-beta.19.dmg
Describe what your company does in 50 characters or less.
Open-Source Networked Thought
What is your company going to make? Please describe your product and what it does or will do.
\- Notetaking app with bi-directional links and block references, which improves users' ability to create and retrieve associations. \- Particular focus on individuals and enterprises that desire security, privacy, and greater power over their data.
Where do you live now, and where would the company be based after YC?
SF / SF or remote
Founders
Please enter the url of a 1 minute unlisted (not private) YouTube video introducing the founder(s). This video is an important part of the application. (Follow the Video Guidelines.)
_(no answer)_
Please tell us in one or two sentences about something impressive that each founder has built or achieved.
Not impressive but fun, the first Lightning Network App: coindesk.com/bitcoin-lightning-risky-maybe-ice-cream-will-tempt
How many founders are on the team?
1
Do any founders have other commitments between X and Y inclusive?
No
Do any founders have commitments in the future (e.g. finishing college, going to grad school), and if so what?
No
Category
Which category best applies to your company?
Other
Progress
How far along are you?
\- 1800 stars on GitHub \- 40 contributors \- 1800 followers on Twitter \- $10k/year in OpenCollective sponsorships \- Inception: March 31st, 2020.
How long have each of you been working on this? How much of that has been full-time? Please explain.
7 months, entirely full-time
Are people using your product?
Yes
How many active users or customers do you have? If you have some particularly valuable customers, who are they? If you're building hardware, how many units have you shipped?
70
Do you have revenue?
Yes
We're interested in your revenue over the last several months. (Not cumulative and not GMV).
800 700 200 200 200 0
Anything else you would like us to know regarding your revenue or growth rate?
Increased when I wrote a post saying how Sponsors would be the first beta testers and get the newest updates first.
Idea
Why did you pick this idea to work on? Do you have domain expertise in this area? How do you know people need what you're making?
1\. Interviewed at Roam, built Athens POC in a week. Open-source makes more sense for this product, and see huge opportunity for individuals and enterprises. twitter.com/tangjeff0/status/1248060649344831488
2\. Product expertise: developer and advocate youtube.com/watch?v=4HXHk5C3bSc twitter.com/tangjeff0/status/1184264669831163904?s=20 twitter.com/fortelabs/status/1180223213919338496?s=20
3\. COSS expertise: Commercial OSS developer and speaker youtu.be/TfulRP3cmXU github.com/interledgerjs/ilp-plugin-mini-accounts/commits?author=tangjeff0 github.com/interledgerjs/ilp-plugin-btp/commits?author=tangjeff0 github.com/interledgerjs/ilp-connector/commits?author=tangjeff0
What's new about what you're making? What substitutes do people resort to because it doesn't exist yet (or they don't know about it)?
Athens delivers the same primitives as Roam, but gives users more security, privacy, and power over their application and data.
Long-term will out innovate Roam as well via open-source.
Who are your competitors, and who might become competitors? Who do you fear most?
Roam and Notion.
Fear an open-source competitor more.
What do you understand about your business that other companies in it just don't get?
Just how critical open-source will be for innovation and value creation.
How do or will you make money? How much could you make?
We currently support the project based on sponsorships of $10k/year.
We will provide a cloud-hosted SaaS.
The office software space is $80B market, and grows at a rate of ~$1B per year.
Notetaking is the first killer app. After dominating this niche, will create a suite of products that replace CRM, CMS, internal wiki, etc. to capture a large percentage of this market.
How will you get users? If your idea is the type that faces a chicken-and-egg problem in the sense that it won't be attractive to users till it has a lot of users (e.g. a marketplace, a dating site, an ad network), how will you overcome that?
Serve C-Suite, consultants, investors insanely well. Rest of the organization will follow.
Equity
Have you incorporated, or formed any legal entity (like an LLC) yet?
No
Legal
Who writes code, or does other technical work on your product? Was any of it done by a non-founder? Please explain.
I do technical work on the product. We've had ~30 code contributors and ~5 design design contributors.
Others
Please tell us something surprising or amusing that one of you has discovered.
I learn 100x more from founders than anyone else.
Keep reading
The rest of this article: He got into YC solo with 70 users and an open-source Roam. Within four years he had sold a beet-meal business to Bryan Johnson.
The remaining sections are behind this point.
It costs an email address. The same address goes on Makersfuel, the MakersClaw briefing that runs Tuesday to Saturday, and every issue carries an unsubscribe link.
The address is used for the newsletter and nothing else. Privacy.
