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Fastest growing S18 companies

The 33 YC S18 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
Titan is an award-winning wealth manager with a mission to increase…
75+53%+103%4$73MUndisclosed round$58M, Jan 2023
2
AI-enabled ordering for medical equipment & supplies
246+29%+64%4$3MSeed$3M, Mar 2021
3
Building Clinical Superintelligence.
541+20%+54%YC$29.1MUndisclosed round$7.9M, Apr 2024
4
Autonomous drones to help warehouses scan inventory.
46+15%+21%0$46MUndisclosed round$20M, Aug 2026
5
Lending Intelligence Software
103+14%+41%3$12.1MSeries A$12M, Jul 2021
6
Trends prediction for marketers
33+14%+22%2$1.8MSeed$1.8M, Jun 2019
7
The space infrastructure services company
67+14%+24%0$237MPost-IPO equity$25M, Jun 2026
8
Build and grow your app business
185+13%+41%9$119MSeries C$50M, May 2025
9
Rebellyous Foods is a food manufacturing technology and production…
18+13%+6%0$43.5MSeries B$2.4M, Jan 2025
10
We at Leena AI build a virtual assistant that answers employee's…
327+11%+25%20$41MUndisclosed round$1M, Oct 2026
11
Building a world where alternative proteins are no longer alternative.
548+11%+18%0GrantAug 2018
12
Your AI agent for creating anything customer-facing, in minutes.
52+8%−4%3$71.6MSeries B$50M, Apr 2022
13
AIoT monitoring, workflow, and evidence systems for regulated labs.
26+8%+8%0$120KSeed$120K, Jul 2019
14
Your AI-powered creative apprentice 🪄
14+8% 0$3.1MSeed$3.1M, Feb 2022
15
Making low cost versions of high cost generic drugs.
144+7%+19%12SeedJan 2018
16
Manage your ledgers and avail Financial Services like Lending on your…
893+7%+12%0$187MSeries C$100M, Aug 2021
17
Fermentation-derived natural products to solve health problems
15+7%+7%0$7.6MUndisclosed round$7.5M, Oct 2022
18
AI Document Fraud Detection for Banks, Credit Unions & Lenders
46+7%+7%2$38.7MSeries B$25M, Jan 2023
19
Modernizing the hospitality tech stack.
401+7%+35%33$177MSeries D$80M, Jun 2025
20
Shopify for experiences
65+7%−2%1$59.6MSeries A$10M, Oct 2026
21
Robotic human cell manufacturing
49+7% 4$20.8MSeries A$19M, Nov 2023
22
Wealth manager
149+6%+17%12$59.1MUndisclosed round$4.2M, Feb 2024
23
Connecting Survivors to Careers in Tech
62+5% 0$270KGrant$150K, Sep 2026
24
Enabling next generation medicines. A comprehensive platform and…
21+5%−5%0$59.5MSeries A$55M, Jan 2022
25
Simple and secure bookkeeping for Indian businesses.
146+4%+7%0$84.2MNon-equity support$67M, Aug 2021
26
Payment operations tools for money movement.
127+4%−15%YC$183MSeries C$50M, Mar 2022
27
Honeylove makes functional undergarments for women
120+3%+8%0$16MSeries A$13M, Sep 2019
28
Skills-based talent management solutions for a dynamic workforce.
65+3%+20%YC$2MSeed$2M, Dec 2022
29
One-stop-shop for flexible family care
1,078+3%+8%1$241MSeries D$150M, Nov 2021
30
Learning Hub for companies in Latam
235+3%−7%0$34.9MSeries B$25M, Jan 2022
31
Consumer fintech for Indonesia
939+2%+15%23$515MSeries C$270M, Aug 2026
32
Logistic Management System for E-commerce & Retail in Mexico.
534+2%+8%36$27MSeries B$20M, Aug 2022
33
An online provider for greater mental health
143+1%+6%YC$53.3MGrant$2M, May 2022

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 S18 companies

How many YC S18 companies are there?

131 companies were in Y Combinator's Summer 2018 batch (S18); 77 are active.

Which YC S18 companies are hiring?

22 companies posted roles in the last 60 days, led by SkydropX (36 roles), Canary Technologies (33 roles) and Ajaib (23 roles). 28 mark themselves as hiring on YC's directory.

Which YC S18 companies are growing fastest?

By team growth over 6 months (10+ people): Titan (+53%), Verse Medical (+29%) and Eden (+20%).

Which YC S18 companies raised the most?

Largest latest rounds in the last 12 months, after their YC batch: Ajaib ($270M), Within ($70M) and Corvus Robotics ($20M).

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