Get an API keyGet an API keyThe 9 YC S12 companies whose team grew the most in the last 6 months (active companies with 10+ people).
Updated weekly, last on November 9, 2026. Roster from Y Combinator's public directory.
| # | Company | Team | 6 mo | 12 mo | Open roles | Total raised | Last round |
|---|---|---|---|---|---|---|---|
| 1 |  The best way to launch, manage and measure social impact programs | 246 | +9% | +7% | 7 | $156M | Undisclosed round$91.5M, Aug 2024 |
| 2 |  Secure Collaboration for Technical Teams | 169 | +5% | +8% | 8 | $73.5M | Series B$50M, Jun 2019 |
| 3 |  Communication app for K-8 teachers, kids, and families | 523 | +4% | +1% | 1 | $191M | Undisclosed round$125M, Apr 2024 |
| 4 |  The easiest way to automate your work. | 1,530 | +3% | +8% | 12 | $1.4M | Undisclosed round$1.4M, Apr 2024 |
| 5 |  Unlocking the power of biotech with modern software for modern science | 813 | +3% | +3% | 4 | $412M | Series F$100M, Nov 2021 |
| 6 |  Marketplace for grocery delivery and pickup | 25,483 | +2% | +5% | 85 | $2.9B | Private equity$232M, Nov 2021 |
| 7 |  Marketing analytics for the world's biggest brand marketers | 56 | +2% | −2% | 0 | $21.7M | Series B$14M, Jul 2018 |
| 8 |  Marketplace connecting consumers to financial advisors | 282 | +2% | +1% | 2 | $161M | Secondary$110M, Aug 2021 |
| 9 |  Private sector Healthcare.gov. | 255 | +2% | +3% | 2 | $6.6M | Undisclosed round$6.6M, Feb 2017 |
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
83 companies were in Y Combinator's Summer 2012 batch (S12); 22 are active.
11 companies posted roles in the last 60 days, led by Coinbase (91 roles), Instacart (85 roles) and Zapier (12 roles). 4 mark themselves as hiring on YC's directory.
By team growth over 6 months (10+ people): Submittable (+9%), Mattermost (+5%) and ClassDojo (+4%).
No reported rounds after their YC batch in the last 12 months.