What they do:
Using protein coupling to build new therapies
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HQ: San Francisco, CA, United States
Y Combinator Summer 2021 Startups
This list has 391 startups and was last updated on Oct 15, 2026. 86 of them are hiring right now. Biggest hubs: San Francisco (100), New York (36), and London (19). Largest teams: LemFi, ShipBlu, and Yummy. Latest round: Onebrief raised $151M (Oct 14, 2026).
391 startupsPage 7 of 11
What they do:
Mobile first solution for Payroll, employee & expense management
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What they do:
Loan management software for private lenders
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Bree
Hiring
What they do:
Chime for Canada, starting with cash advances
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Buoyant Aero
Hiring
What they do:
Bringing back blimps
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HQ: New York, NY, United States
What they do:
Compound B2B SaaS for modern infrastructure to deploy and manage sites
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HQ: Atlanta, GA, United States
What they do:
Virtual Co-working Community
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HQ: San Francisco, CA, United States
What they do:
Make games and stories with AI
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HQ: Ho Chi Minh City, Vietnam
What they do:
Building the next generation food ingredient champion.
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What they do:
Project management on a live map
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What they do:
The personal coach and companion for cyclists.
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HQ: Truckee, CA, United States
What they do:
Reading + Writing Club App for Kids
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HQ: Miami, FL, United States
What they do:
Square for Europe
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HQ: Utrecht, Netherlands
What they do:
AI-designed Affinity Reagents
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HQ: Austin, TX, United States
What they do:
The complete production quality platform. AI-powered E2E testing,…
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HQ: Limerick, Ireland
What they do:
Community for 100M Indian Financial Market Traders & Investors
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What they do:
Single photo nutrition tracking.
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HQ: New York, NY, United States
Zen
Hiring
What they do:
Posture correction software
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HQ: New York, NY, United States
YC S21Early stage
What they do:
We help high-growth startups go viral on autopilot
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HQ: London, United Kingdom
LootRush
Hiring
What they do:
The global operating account you truly deserve.
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HQ: San Francisco, CA, United States
What they do:
One-hour antibiotic sensitivity testing
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HQ: Baltimore, MD, United States
What they do:
Bare-metal access to Brazil's Open Finance and Pix systems
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What they do:
A white-label care enablement platform
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HQ: New York, NY, United States
What they do:
The career community for healthcare workers
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HQ: San Francisco, CA, United States
What they do:
AI-powered equity research software
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What they do:
A platform to make artificial viruses as cancer therapeutics.
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HQ: New York, NY, United States
What they do:
Student Attendance tracking for Public Schools
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HQ: Dallas, TX, United States
What they do:
Workflows for repetitive customer-facing tasks
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What they do:
We make bacteria and plants that clean up pollution.
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HQ: San Francisco, CA, United States
What they do:
Activating an overlooked force in medicine - the patient.
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HQ: San Francisco, CA, United States
What they do:
2 sided Marketplace for accelerating medical research
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HQ: San Francisco, CA, United States
What they do:
Developing milk-inspired therapeutics for infectious diseases
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HQ: Davis, CA, United States
What they do:
Transforming pharmacies in the UK into diagnostic centers
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HQ: London, United Kingdom
What they do:
Get data insights without writing SQL
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HQ: London, United Kingdom
What they do:
The dynamic single-cell analysis company
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HQ: Houston, TX, United States
What they do:
Regulating the immune system to block cancer & autoimmune diseases
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HQ: Philadelphia, PA, United States