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Fastest growing W25 companies

The 43 YC W25 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 43 of 43 companies on this list
#CompanyTeam6 mo12 moOpen rolesTotal raisedLast round
1
The data layer for perceptual intelligence
44+300%+450%2$24MSeries A$20M, Aug 2026
2
Frontier Video Agents
13+117%+117%YC$500KYC investment$500K, Mar 2025
3
AI-native ATS/CRM for recruiting firms
47+96%+327%2$24.2MSeries A$21M, Sep 2026
4
The OS for hospital workforce management
17+70%+240%YC$500KYC investment$500K, Mar 2025
5
Foundational model of human societies for consequential decisions
22+69%+120%0$5.1MSeed$3.3M, Aug 2025
6
AI tutors for exam prep
10+67% YC$500KYC investment$500K, Mar 2025
7
AI compliance co-pilot for regulated financial businesses
16+60% 0SeedMar 2025
8
Applied research lab curating data solutions for foundation model…
286+58%+186%25$30.5MSeries B$30M, Sep 2026
9
Ergo is the context layer that helps revenue teams close more deals.
11+57%+83%YC$3.3MSeed$2.8M, Jun 2026
10
High Thrust Space Vehicles for Satellite Defense
26+53%+117%1$8.8MSeed$8.8M, Aug 2025
11
AI agents for CX teams, starting with training and QA.
43+48%+187%2$32.7MSeries A$25M, Apr 2026
12
AI Accountant for Accounting Firms
16+45%+129%YC$1.5MSeed$1M, Mar 2026
13
Making humanoids dexterous enough to thread a needle
17+42%+31%YC$11MSeed$11M, Jun 2026
14
AI-native commercial insurance brokerage
85+35%+158%14$47.5MSeries A$47M, Feb 2026
15
AI-powered student information system for K-12 schools
16+33%+100%YC$500KYC investment$500K, Mar 2025
16
AI to understand and then route engineering work
25+32%+127%2$18.2MSeries A$13.5M, Jul 2026
17
Query mission-critical video
22+29%+69%0$14.4MSeed$7M, Mar 2026
18
AI estimating & detailing for Division 8 doors, frames & hardware
10+25%+67%1$3.6MSeed$3.1M, Jul 2025
19
AI tutor starting with maths and science
10+25%−9%0$500KYC investment$500K, Jan 2026
20
Autonomous patrol-boats for National Security
10+25%+43%YC$4.7MSeed$4.2M, Jul 2026
21
Manufacturing the most powerful chips, 15x faster
10+25%+25%0$500KYC investment$500K, Jan 2026
22
AI-powered Patient Identification for Clinical Trials
12+20%+33%YC$500KYC investment$500K, Jan 2026
23
Agentic Sales Platform
12+20%+50%YC$500KYC investment$500K, Mar 2025
24
The Javascript framework for building AI agents, from the Gatsby devs
62+19%+44%0$35MSeries A$22M, Apr 2026
25
Supply chain superintelligence for distribution and procurement
26+18%+37%3$5.5MSeed$5M, Oct 2025
26
We help law enforcement solve crime
13+18%+160%YC$7MSeed$7M, Mar 2025
27
Global B2B Stablecoin Processor
20+18%+43%2
28
awen translates intent into exceptional visuals through conversation
14+17%+75%0$500KYC investment$500K, Mar 2025
29
AI quote & order processing for technical distributors & manufacturers
24+14%+4%YC$2.6MSeed$2.1M, Dec 2025
30
AI Teacher Assistant for Grading Essays
17+13% YC$600KSeed$600K, Jan 2025
31
AI hiring platform powered by expert recruiters
62+13%+130%0$2.8MSeed$2.3M, May 2026
32
Be the Answer in AI Search - AI SEO across SEO, GEO & AEO
20+11%+18%YC$2.7MSeed$2.2M, Mar 2025
33
Open Source React.js Library for AI Chat
10+11%+11%0$500KYC investment$500K, Mar 2025
34
AI systems for aviation
22+10%+29%0$500KYC investment$500K, Mar 2025
35
Production Monitoring & Evals for AI Agents
11+10%+38%YC$2.2MSeed$2.2M, Mar 2025
36
AI for insurance verification & billing at dental clinics
12+9% YCSeedMar 2025
37
Stablecoin API for global payments
12+9%+20%0$3.8MSeed$3.3M, Aug 2025
38
AI Powered CAD
15+7%+50%YC$4.6MSeed$4.1M, Oct 2025
39
Agents for Accelerated Clinical Trial Design
32+7%+19%0$500KYC investment$500K, May 2025
40
AI voice and texting agents
16+7%+60%1$5.2MSeed$4.7M, Mar 2025
41
Platform and marketplace for RL environments and AI data
16+7%+23%YC$16.2MSeries A$14M, Jun 2026
42
Software Enabled CNC Parts Supplier
17+6%+113%YC$500KYC investment$500K, Mar 2025
43
AI-driven exam prep
21+5% 0$5.2MSeed$4.7M, May 2025

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 W25 companies

How many YC W25 companies are there?

166 companies were in Y Combinator's Winter 2025 batch (W25); 159 are active.

Which YC W25 companies are hiring?

15 companies posted roles in the last 60 days, led by AfterQuery (25 roles), Harper (14 roles) and SalesPatriot (3 roles). 66 mark themselves as hiring on YC's directory.

Which YC W25 companies are growing fastest?

By team growth over 6 months (10+ people): Mundo AI (+300%), Mosaic (+117%) and Spott (+96%).

Which YC W25 companies raised the most?

Largest latest rounds in the last 12 months, after their YC batch: Harper ($47M), AfterQuery ($30M) and Solidroad ($25M).

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