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YC Defense companies

32 Y Combinator companies in Defense, with team size, growth, open roles and funding.

Updated weekly, last on November 9, 2026. Roster from Y Combinator's public directory.

Hiring the mostlast 60 days
10 roles
9 MothersX26
  1. 2Icarus5
  2. 3Hop Aero2
See all 3
Fastest growingteam, 6 months
+120%
9 MothersX26
  1. 2Icarus+46%
  2. 3Perseus Defense+38%
See all 7
Raised the mostlast 12 months
$11M
Hop AeroS26
  1. 2DAIVIN!$9M
  2. 3Conntour$7M
See all 3
Companies
32
Active
32
Hiring, last 60 days
3
Open roles, 60 days
17
People on these teams
265
Showing 32 of 32 companies
CompanyBatchTeam6 mo12 moOpen rolesTotal raisedLast round
Stratospheric birds for defense
F2573+46%+143%5$650KYC investment$500K, Dec 2025
Drone submarines
S2535+30%+59%0$6.5MSeed$6.5M, Sep 2025
Counter Drone Systems. $1.6m sales. We delivered for the DoW.
X2622+120%+214%10$500KYC investment$500K, Jun 2026
Query mission-critical video
W2522+29%+69%0$14.4MSeed$7M, Mar 2026
Building The Next Generation of Night Vision Devices
W2419+6%+36%YC$6MSeries A$5.5M, Sep 2025
Rocket cargo delivery to contested environments
S2616+23%+33%2$11MSeed$11M, Sep 2026
America's Golden Dome for Drones
S2511+38% YC$6.5MSeed$6M, Sep 2025
Modular AI-Commanded Drones for Defence
W267  YC$500KYC investment$500K, Apr 2026
Air-breathing hypersonics for scale.
F256 +20%YC$500KYC investment$500K, Dec 2025
USA-made magnetics for robotics and defense.
S265  0$500KYC investment$500K, Aug 2026
Making Defense Manufacturing Faster and Cheaper
S265  YC
Submarine drones for defense
X265  0$500KYC investment$500K, Jun 2026
Military exoskeletons
S264  YCPre-seedAug 2026
Air Defense as a Service for Civilian Infrastructure.
S264  YC
The hardware-agnostic operating system for drone defense
X264  0
ApolloShield is a system that detects unwanted drones and drives them…
S164 −20%0$2.6MSeed$2.5M, Apr 2018
Autonomous drones that fly and swim
F263  0
Drone swarm defence at a small-unit level
S263  0
Mass-deployable radars for air defense
S263  YC
End-to-end Simulation for Defense Autonomy
F253  0$500KYC investment$500K, Dec 2025
Precision navigation for UAVs operating without GPS.
F262  0
Kill the drone, keep the jet. Reusable unmanned interceptors.
F262  0
Track drones and missiles without radars - Accurate, Passive, Scalable
X262  YC
Autonomous street sweeping as a service by retro-fitting vehicles
W212  0$230KYC investment$125K, Apr 2021
Discover novel defense related materials/molecules.
F261  0
Mass-produced AI strike systems and Counter-UAS
S261  0SeedAug 2026
Tankless Dive Gear - Breath Autonomy at Sea, Land & Space
W261  0$9MPre-seed$9M, Mar 2026
Anti-drone defense for the maritime domain
F26  
AI-guided ballistic missiles, built for mass manufacturing
F26  0
The highest performance modular battery packs for mobility/vehicles
F26  YC
Building drone swarms that hunt hidden enemies.
S26  
Air-gapped compute for defense contractors
X26  

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 Defense companies

How many YC Defense companies are there?

32 Y Combinator companies are in Defense; 32 are active.

Which YC Defense companies are hiring?

3 companies posted roles in the last 60 days, led by 9 Mothers (10 roles), Icarus (5 roles) and Hop Aero (2 roles). 12 mark themselves as hiring on YC's directory.

Which YC Defense companies are growing fastest?

By team growth over 6 months (10+ people): 9 Mothers (+120%), Icarus (+46%) and Perseus Defense (+38%).

Which YC Defense companies raised the most?

Largest latest rounds in the last 12 months, after their YC batch: Hop Aero ($11M), DAIVIN! ($9M) and Conntour ($7M).

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