117 Y Combinator companies based in Boston, with team size, growth, open roles and funding.
Updated weekly, last on November 9, 2026. Roster from Y Combinator's public directory.
| Company | Batch | Team | 6 mo | 12 mo | Open roles | Total raised | Last round |
|---|---|---|---|---|---|---|---|
A mental health benefits platform for employers. | W18 | 920 | +2% | −1% | 5 | $167M | Series D$74M, Feb 2021 |
Our mission is to make biology easier to engineer. | S14Public | 487 | −7% | −24% | 1 | $1.6B | Grant$775M, Apr 2024 |
The only R&D data cloud for life sciences | S15 | 227 | +6% | +32% | 13 | $114M | Undisclosed round$15M, Feb 2026 |
The AI negotiation agent to help you save money on SaaS. | S19Acquired | 192 | −10% | −13% | 0 | $216M | Series B$150M, Jun 2022 |
Generative AI powered Shopify for home service professionals | W21 | 168 | +7% | +27% | 5 | $44M | Series B$27M, Aug 2025 |
Instant, no fee international remittances. | W12Acquired | 123 | −2% | −4% | 0 | ||
Easiest way for companies to process data requests from governments | S21 | 99 | +22% | +62% | 5 | $41.2M | Series A$21.2M, Sep 2025 |
Raptor Maps builds software to manage the solar PV lifecycle. | S16 | 96 | −14% | −14% | 1 | $62.2M | Series C$35M, Dec 2024 |
Advertising for the new internet | W23 | 93 | +3% | +19% | YC | $10M | Series A$10M, May 2026 |
At-Home health monitoring with silicon photonic chips for data centers | S20 | 81 | +11% | +31% | 1 | $32.8M | Series A$17M, Mar 2025 |
We Create Superior Data By Making Annotation Competitive | W19 | 81 | +5% | +9% | YC | $35.4M | Series B$16.2M, Oct 2024 |
Blood Test for Early Detection of Ovarian Cancer | S21 | 56 | +2% | +2% | 0 | $24.5M | Grant$17M, May 2026 |
EOR for the staffing industry | W19Acquired | 51 | +9% | +6% | 0 | SeedMar 2019 | |
Unlocking the utility of genomics for the world. | W19 | 50 | −4% | 1 | $32.7M | Undisclosed round$12.7M, Jan 2024 | |
Multimodal AI Platform for Modality Agnostic Drug Discovery™ | W19 | 50 | −2% | −6% | 0 | $26.6M | Undisclosed round$550K, Oct 2024 |
Medicinal Chemistry powered by Machine Learning | W20 | 41 | −5% | −9% | 1 | $26.4M | Grant$24M, May 2022 |
Enterprise-Grade OpenTelemetry | W23 | 35 | +21% | 0 | $13.5M | Series A$13M, Sep 2024 | |
A national network of microschools bringing school choice to every… | S21 | 34 | −11% | YC | $1.6M | Seed$1.5M, Jan 2024 | |
Data integration & insights for state and local governments | W17 | 34 | +21% | +26% | 3 | $3.2M | Seed$3.1M, Jan 2018 |
Agents for Accelerated Clinical Trial Design | W25 | 32 | +7% | +19% | 0 | $500K | YC investment$500K, May 2025 |
We make injections as easy as pushing a button! | S21 | 31 | +15% | +29% | YC | ||
Non-profit building open-source voting machines for US elections. | W19 | 31 | +19% | +29% | 0 | SeedMar 2019 | |
Discovering bispecific antibody drug-conjugates (BsADC) against cancer | W21 | 30 | −3% | +7% | 0 | $11.9M | Seed$11.8M, Oct 2025 |
The AI Support Agent for Ecommerce | W23 | 28 | −18% | +22% | 0 | $5M | Seed$5M, Oct 2024 |
We use AI to design antibodies for intractable diseases | S20 | 28 | +22% | +40% | 1 | $37.4M | Series A$26M, May 2024 |
AI-native Robotics | S20 | 27 | +29% | +35% | YC | Corporate roundAug 2026 | |
Population health analytics powered by wastewater. | W18 | 26 | −7% | −4% | 0 | $41.4M | Series A$13.4M, Jun 2025 |
The No Infrastructure Platform as a Service | S14Acquired | 24 | −14% | 0 | $12.1M | Series A$12M, Jun 2019 | |
Helping low-income Americans overcome debt and rebuild credit at… | W19 | 23 | −4% | −4% | YC | $4.5M | Grant$4.2M, Sep 2024 |
Neural interfaces to understand and use nerve data in medicine. | W17 | 23 | −8% | −8% | 0 | $46.8M | Undisclosed round$20M, Jan 2024 |
Kernal is creating mRNA 2.0 therapies that work in specific cells | S20 | 21 | +5% | +40% | 3 | $73M | Grant$48M, Oct 2025 |
Electricity price forecasts for energy storage, ev charging, etc. | W21Acquired | 17 | −6% | −6% | 0 | $1.7M | Equity crowdfunding$57K, May 2022 |
Metal manufacturing, faster, cheaper, and more versatile. | S26 | 16 | +167% | 0 | |||
Plaid for Commercial Real Estate | W23 | 15 | +15% | +36% | 0 | $3.3M | Seed$3.3M, Oct 2023 |
Patent-pending enzymes to break down common dietary triggers | S21 | 15 | +15% | +36% | 0 | $1.6M | Seed$1.5M, Oct 2021 |
Next-generation mRNA platform to solve cancer, COVID and climate. | W17 | 15 | 0% | −12% | 0 | $60M | Series A$231K, Apr 2024 |
Create custom NLP models | S22 | 14 | +27% | +8% | 0 | $3.5M | Seed$3M, Mar 2023 |
We make the most compact nuclear reactors | X26 | 13 | +117% | 0 | $32.1M | Undisclosed round$620K, Sep 2026 | |
Live intelligence for biopharma teams. | S23 | 13 | +18% | +86% | YC | $3.6M | Seed$3.1M, Apr 2025 |
Automated tooth cutting for dentists using imaging, AI and robotics | W20 | 13 | −7% | −59% | 0 | $20.3M | Undisclosed round$15M, Jul 2025 |
A nonprofit stool bank enabling access to fecal transplants. | W20 | 13 | −7% | +8% | 0 | $100K | Grant$100K, Jan 2022 |
Next-Generation Surgical Navigation and Robotics | S19 | 12 | 0% | 0% | 0 | $13.9M | Series A$5M, Jan 2025 |
Personal gaming coach for PC gamers globally | S21Inactive | 11 | 0% | 0% | 0 | $3.1M | YC investment$125K, Aug 2021 |
coaching agents for athletes | F24 | 10 | 0% | −9% | 0 | ||
Financial Platform for Migrant Families in America | S21 | 9 | 0 | $200K | YC investment$200K, Jun 2021 | ||
Data platform for metagenomics and the microbiome. | S14Acquired | 9 | 0% | 0% | 0 | $120K | Undisclosed round$120K, Jan 2017 |
XGenomes is building the sequencing technology of the future. | W19 | 8 | −20% | −20% | 0 | $200K | Grant$200K, Sep 2019 |
Robots for the inspection and maintenance of data centers | X25 | 7 | 0 | $500K | YC investment$500K, Jun 2025 | ||
Gen-AI Designed Enzymes for Pharmaceutical Innovation | W23 | 7 | +17% | +17% | 0 | $500K | YC investment$500K, Apr 2023 |
Recover failed subscription payments to increase retention and LTV | S22 | 7 | −12% | −12% | 0 | SeedOct 2023 |
Every launched company in YC's public directory, with its batch, status, industry and location. New companies show up the week YC lists them.
Each company is matched to Crustdata by its website. Crustdata adds team size and its change over 6 and 12 months, open roles from job postings, reported funding, and founders' past employers.
Hiring the most counts distinct roles posted in the last 60 days. Growth needs 10+ people today, shrinking 20+ a year ago, so tiny teams do not top the lists. Rebuilt every week.
The numbers on this page come from three Crustdata API calls. Crustdata tags 5,000+ companies with Y Combinator as an investor; swap the filter for any investor, industry or headcount range and track your own list, with founders' work emails one call away.
# 1. every company with Y Combinator as an investor curl https://api.crustdata.com/company/search \ -H "authorization: Bearer $CRUSTDATA_API_KEY" \ -H "x-api-version: 2025-11-01" \ -d '{ "filters": { "field": "funding.investors", "type": "in", "value": ["Y Combinator"] }, "fields": ["basic_info.name", "headcount.total", "headcount.growth_percent", "funding.total_investment_usd"], "limit": 100 }' # 2. open listings per company, last 60 days (limit 0 = counts only) curl https://api.crustdata.com/job/search \ -H "authorization: Bearer $CRUSTDATA_API_KEY" \ -H "x-api-version: 2025-11-01" \ -d '{ "filters": { "op": "and", "conditions": [ { "field": "company.basic_info.company_id", "type": "in", "value": [...] }, { "field": "metadata.date_added", "type": "=>", "value": "2026-08-24" } ]}, "limit": 0, "aggregations": [{ "type": "group_by", "field": "company.basic_info.company_id", "agg": "count" }] }' # 3. the same company filter as a weekly watch: POST /watch/company/search
117 Y Combinator companies are based in Boston; 71 are active.
12 companies posted roles in the last 60 days, led by TetraScience (13 roles), Modern Health (5 roles) and Topline Pro (5 roles). 19 mark themselves as hiring on YC's directory.
By team growth over 6 months (10+ people): Ultrasonium (+167%), Apollo Atomics, Inc. (+117%) and Nextera Robotics | DIDGE.ai (+29%).
Largest latest rounds in the last 12 months, after their YC batch: TetraScience ($15M), Vector ($10M) and Apollo Atomics, Inc. ($620K).