Paul Buchheit
Partner @ Y Combinator
Mountain View, United States
Paul Buchheit is a seed investor at Y Combinator in Mountain View focused on Software and Artificial Intelligence. Paul Buchheit is based out of Mountain View, California and is the Co-Founder and General Partner of Standard Capital. Paul Buchheit attended Case Western Reserve University.
- Total investments:
- 157
- Last investment:
- Lead investor:
- 7%
Last updated:
For AI agents: llms.txt
Industries Paul Buchheit invests in
Stages Paul Buchheit invests in
Countries Paul Buchheit invests in
Round sizes
Contacts
| Type | Contact | Validation |
|---|---|---|
| Work email | ||
| Personal email | ||
| Work phone | ||
| Personal phone | ||
| Socials |
Round size
- Seed
- $1.1M–$5M
- Angel
- $100k–$1.6M
- Series A
- $2.5M–$14M
Investment Focus
Industry
- Software 43 (27%)
- Artificial Intelligence 18 (11%)
- SaaS 17 (11%)
- E-Commerce 17 (11%)
- Health Care 17 (11%)
Stage
- Seed 109 (69%)
- Series A 23 (15%)
- Angel 8 (5%)
- Series B 5 (3%)
- Pre-Seed 3 (2%)
Country
- United States 126 (80%)
- Canada 6 (4%)
- India 4 (3%)
- Singapore 3 (2%)
- Mexico 2 (1%)
Investments
| Company | Description | Round | Links |
|---|---|---|---|
| Weave resloves engineering tasks by merging large language models with targeted machine learning. | $13.5M / Series A / Jul 28, 2026 | ||
| BuildForever build products that feel personal, magical and deeply human. | $9.5M / Seed / Apr 21, 2026 | ||
| Concourse provides worldwide corporations with next-generation treasury management. | $12M / Series A / Jan 27, 2026 | ||
| Sim is a software development company that provides an artificial intelligence platform to automate workflow and sync data. It is an open-source platform for designing, testing, and deploying AI agent workflows. It offers a visual, drag-and-drop canvas—similar to design tools—which lets developers connect large language models with various apps andlogic blocks. Users can integrate Sim with over 500 tools, such as Slack, Gmail, Supabase, and Pinecone, enabling autonomous agents that interact with real-world data and systems. The platform supports both hosted and self-hosted models, giving teams flexibility in choosing how and where their AI runs. Workflows built in Sim can be triggered manually, via scheduled events, or by webhooks, and they can be exposed as APIs or chat interfaces. Sim combines a no-code visual interface with production-grade capabilities like structured output, logging, and debugging, allowing teams to iterate quickly and scale their AI systems. | $7M / Series A / Nov 14, 2025 | ||
| SiPhox offers a handheld testing device with RNA/DNA and protein testing for point-of-care and At-Home solutions. The company's kit is made by multiplexing RNA, antibody, and antigen tests on a single silicon photonic chip which is amplified by plasmon resonance and silicon photonic resonator readout, enabling users to undertake tests fordisease safely and in a disposable point-of-care and at-home manner.SiPhox was founded in 2020 and is based in Cambridge, Massachusetts, USA. | $10M / Seed / Jul 19, 2023 | ||
| Perplexity is a search engine platform that uses artificial intelligence to provide large language models and search engines. The company's platform enables the development of beneficial artificial general intelligence, as well as an open-source environment that is accessible to the public, allowing clients to develop skills and knowledge inartificial intelligence. | $25.6M / Series A / Mar 28, 2023 | ||
| Character.ai provides open-ended conversational applications that let users create characters and converse with them. | $80K / Seed / Jan 24, 2023 | ||
| Cityfurnish is an internet company that specializes in the fields of e-commerce and online rental. It features an online renting zone where contemporary and modern styles amalgamate to establish a new genre of wooden furniture and furnishings. The company was founded in 2015 and headquartered in Gurgaon, Haryana. | $2.5M / Series A / Nov 11, 2022 | ||
| Let’s Do This is an online marketplace that features almost every endurance event on the planet. It helps race organizers to reach an engaged community of participants and endurance sports enthusiasts, offering a dedicated platform to provide detailed event information, news, and special offers. Find and book the best running, triathlon, cyclingand obstacle events in the UK and around the world. Whether it's a 5k fun run or tenth Ironman Triathlon, Let's Do This is the best place to find the perfect race.It was founded in 2016 by Alex Rose and Sam Browne who are both passionate runners and cyclists. It is headquartered in San Francisco, California with an office in London, United Kingdom. | $60M / Series B / Jun 06, 2022 | ||
| Dnovobio is a developer of a direct reprogramming technology intended to create any cell, tissue, or organ on demand. Its company's platform converts skin into functional brain cells. | $2.7M / Seed / Jan 24, 2022 | ||
| See all 157 investments → | |||
Co-Investors
About Y Combinator
Y Combinator invests a standard amount of capital in exchange for equity and through uncapped safe agreements. Participants engage in a three-month intensive cycle that focuses on product development and preparations for fundraising. The firm offers access to a private networking platform for knowledge sharing and hosts events featuring speakers from various sectors. This program culminates in a presentation event where founders showcase their businesses to a curated group of investors.
Y Combinator Contacts
| Name | Phone | Socials | |
|---|---|---|---|
Boris Jabes
Visiting Partner
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Luther Lowe
Head of Public Policy
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Max Kolysh
Visiting Partner
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Brad Flora
Group Partner
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Calvin French-Owen
Visiting Group Partner
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FAQ
What does Paul Buchheit invest in?
Paul Buchheit invests primarily in Software, Artificial Intelligence and SaaS startups, most often at Seed and Series A stage. Most of the 157 investments tracked by Shizune back companies in United States. The Investment Focus section breaks down every industry, stage and country in the portfolio.
What is Paul Buchheit's check size?
Paul Buchheit typically joins rounds of $1.1M–$5M at Seed, $100k–$1.6M at Angel and $2.5M–$14M at Series A. These ranges are 10th–90th percentile round sizes calculated from confirmed public funding rounds, so they are a realistic guide to the rounds Paul Buchheit participates in.
How do I contact Paul Buchheit?
Public channels for Paul Buchheit include LinkedIn, X (Twitter) and the website linked on this profile. For a verified work email and phone number, create a free Shizune account — contact data is searched across 20+ sources and validated before delivery, so your outreach lands in the right inbox.
When did Paul Buchheit last invest?
The most recent investment recorded for Paul Buchheit closed in Jul 2026. Shizune tracks 157 investments in total for this profile, including round sizes, stages and portfolio companies, all sourced from confirmed public funding rounds and refreshed monthly.
Is Shizune's investor data accurate?
Yes — every stat on this profile is calculated from confirmed public funding rounds monitored across hundreds of sources since 2020. This profile was last refreshed in Oct 2026 and is updated monthly. Spotted something off? Use the “Suggest an edit” link near the top of the page.
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