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Fastest growing S25 companies

The 33 YC S25 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.

Showing 33 of 33 companies on this list
#CompanyTeam6 mo12 moOpen rolesTotal raisedLast round
1
Voice AI for Enterprises
50+355%+900%YC$4MGrant$3.5M, Jul 2026
2
Supplying America's Industrial Base
35+218%+600%YC$16.8MSeed$11.5M, Jun 2026
3
AI that makes AI fast
18+200% 2$44.8MSeries A$40M, Sep 2026
4
Secure frontier AI for government & adjacent knowledge work
21+110%+250%YC$10.9MSeed$10.9M, Oct 2025
5
World's largest crowdsourced benchmark for AI-generated design
10+100% 0$500KYC investment$500K, Sep 2025
6
Optimizing fleet planning with data driven algorithms
10+100% YC$500KYC investment$500K, Sep 2025
7
We Bring Customers to Your Dealership
35+94%+289%15$33.5MSeries A$27M, Oct 2026
8
The AI platform for private markets investors
38+90%+81%6$29MSeed$5M, Sep 2026
9
creators of folk.com
13+86%+117%YC$8.2MSeed$6.2M, Oct 2025
10
AI models that teach robots new skills in hours
11+83% YC$500KYC investment$500K, Sep 2025
11
The AI data analyst for biology labs
11+83%+83%YC$500KYC investment$500K, Jul 2025
12
AGI for home service
11+83% YC$500KYC investment$500K, Sep 2025
13
The app platform inside Claude and ChatGPT.
12+71% YC$500KYC investment$500K, Jul 2025
14
AI Native Rippling for Deskless Workers
10+67% YC$3.9MSeed$3.4M, Nov 2025
15
AI accounting for enterprise finance teams
13+63% 1$3.4MSeed$3.4M, Jul 2026
16
Voice AI Agents for Debt Collection
12+50%+71%YC$600KYC investment$500K, Sep 2025
17
Book any load in 10 minutes
14+40%+56%YC$500KYC investment$500K, Jan 2026
18
We automate creator marketing for the world's largest brands
33+38%+57%YC$500KYC investment$500K, Sep 2025
19
America's Golden Dome for Drones
11+38% YC$6.5MSeed$6M, Sep 2025
20
Reshoring critical metal production
11+38% 0$500KYC investment$500K, Sep 2025
21
Crazy fast, open source infra for AI agents to use the Internet
24+33%+167%0$22.6MSeries A$16M, Oct 2025
22
Email Inboxes for AI Agents
13+30% 3$6.5MSeed$6M, Mar 2026
23
AI agents for distributors and manufacturers to automate order entry.
13+30% 5$500KYC investment$500K, Sep 2025
24
Drone submarines
35+30%+59%0$6.5MSeed$6.5M, Sep 2025
25
AI agents for the consumer lending industry
22+29%+144%3SeedSep 2025
26
Consumer focus groups run by AI
10+25%+11%0$500KYC investment$500K, Sep 2025
27
The Global Dollar App for Brazil
31+24%+63%0$5.1MSeed$4.6M, Feb 2026
28
Replacing the restaurant phone line with Voice AI
11+22%+38%0$500KYC investment$500K, Sep 2025
29
Making AI run fast on any hardware.
13+18%+44%YC$35MUndisclosed round$29.2M, Oct 2026
30
We help products get discovered & used by AI agents.
20+18%+43%YC$7MSeed$6.5M, Oct 2025
31
The Cross-Border Neobank for the Middle East
14+17%+40%0$3MSeed$3M, Aug 2025
32
Your personal AI for language learning
33+14%+83%0$500KYC investment$500K, Sep 2025
33
Hill-climb any benchmark, for any model, in any domain.
16+7%+129%2$9.5MSeed$9M, Aug 2026

How this works

1. The roster

Every launched company in YC's public directory, with its batch, status, industry and location. New companies show up the week YC lists them.

2. The numbers

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.

3. The lists

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.

Built with Crustdata. Get your own API key and build your own.

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.

  • Company search for team size, growth and funding
  • Job search with a count by company, for who is hiring and for what
  • A watch that re-runs the search weekly and sends only what changed
# 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

Questions about YC S25 companies

How many YC S25 companies are there?

165 companies were in Y Combinator's Summer 2025 batch (S25); 158 are active.

Which YC S25 companies are hiring?

14 companies posted roles in the last 60 days, led by Flai (15 roles), F2 (6 roles) and Comena (5 roles). 69 mark themselves as hiring on YC's directory.

Which YC S25 companies are growing fastest?

By team growth over 6 months (10+ people): Freya (+355%), Nox Metals (+218%) and Wafer (+200%).

Which YC S25 companies raised the most?

Largest latest rounds in the last 12 months, after their YC batch: Wafer ($40M), Halluminate ($30M) and Luminal ($29.2M).

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