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Fastest growing W18 companies

The 31 YC W18 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 31 of 31 companies on this list
#CompanyTeam6 mo12 moOpen rolesTotal raisedLast round
1
Vena Medical is providing physicians with the world's smallest camera…
26+30%−7%0$198KYC investment$40K, Feb 2018
2
ZBiotics makes genetically engineered probiotics.
71+16%+25%6$17.2MSecondary$12M, Mar 2025
3
Automating payroll for Latin America.
210+12%+17%YCSeries ASep 2021
4
'Figma/Canva for scientists’
266+11%+20%9$17MSeries A$15.3M, Apr 2023
5
Health insurance for remote teams
184+10%+27%YC$47.1MSeries B$35M, Apr 2022
6
Flat-fee patent & trademark counsel with top firm results
11+10%+10%0$2.8MSeed$2.8M, Jul 2019
7
Helloverify is a background screening platform (Checkr for India).
641+9%+12%YC$120KSeries A$120K, Mar 2019
8
96+9%+20%1$18.1MSeries A$15M, Nov 2018
9
Sourcify helps brands manufacture products in Asia.
13+8%+30%YC$4.9MConvertible note$2.5M, Mar 2018
10
Tax filing automation for individuals in Latam.
85+8%+29%0$120KSeed$120K, Apr 2021
11
All-in-one Finance OS for businesses
1,183+7%+10%6$300MSeries C$100M, Feb 2023
12
Analytics to improve how teams work and collaborate
15+7%+7%0SeedJan 2018
13
Making Anime Real
33+6%+18%1$120KSeed$120K, Aug 2018
14
Vanta, the proven leader in automated compliance helping startups…
1,993+6%+34%9$503MSeries D$150M, Jul 2025
15
Contact center AI platform.
358+6%−15%3$214MSeries C$125M, Apr 2022
16
Anjuna enabled organizations to trust any infrastructure
35+6%+13%0$67.1MSeries B$25M, Aug 2024
17
Agile commission software to design, deploy & adapt commission plans.
284+6%+12%2$165MSeries C$100M, Jan 2022
18
The self-maintaining knowledge base
42+5%+11%0$15.4MSeries A$11M, Apr 2020
19
Create remarkable client experiences
44+5%+13%1$10MSeries A$10M, Jan 2023
20
Replacing orthodontic braces with our clear aligner and software
22+5% YC$8MUndisclosed round$7.8M, Feb 2020
21
24/7 pediatric clinic in every family's living room
83+4%+9%3$7.7MSeed$4M, Jan 2022
22
Bookkeeping, tax, & tax credits on autopilot for 2,000+ startups
117+4%+13%YC$10MSeed$7M, Nov 2024
23
Swayable predicts consumer opinion and the impact of content
64+3%+25%9SeedMay 2019
24
Making financial services simple, transparent and delightful.
3,191+3%+13%6$1.3BPost-IPO secondary$183M, Sep 2026
25
The world's first digital clinic for substance use management
176+3%+5%1$152MSeries C$58M, Mar 2024
26
Order ahead at restaurants and get rewards with friends.
78+3%−8%0$95.6MSeries B$70M, Jun 2021
27
Shogun empowers brands to create exceptional ecommerce experience.
241+3%+6%0$115MSeries C$67.5M, Jun 2021
28
Better payment systems for governments and the communities they serve.
252+2%+8%1$48.1MSeries B$25M, Feb 2022
29
Super is the first and leading Indonesian social commerce platform
223+2%−12%0$105MSeries C$70M, Jun 2022
30
Embedded banking software platform and marketplace
56+2%+2%1$71.5MSeries C$40M, Sep 2022
31
A mental health benefits platform for employers.
920+2%−1%5$167MSeries D$74M, Feb 2021

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 W18 companies

How many YC W18 companies are there?

146 companies were in Y Combinator's Winter 2018 batch (W18); 77 are active.

Which YC W18 companies are hiring?

24 companies posted roles in the last 60 days, led by Replit (10 roles), Swayable (9 roles) and BioRender (9 roles). 25 mark themselves as hiring on YC's directory.

Which YC W18 companies are growing fastest?

By team growth over 6 months (10+ people): Vena Medical (+30%), ZBiotics (+16%) and Runa (+12%).

Which YC W18 companies raised the most?

Largest latest rounds in the last 12 months, after their YC batch: Replit ($400M), Culture Biosciences ($80M) and Jasper.ai ($400K).

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