Karma VS React Testing Library
As of 30 October 2026, React Testing Library is named by 335 companies and Karma by 248; Karma skews to companies under 200 people (46% vs 57%), React Testing Library to companies over 1,000 (20% vs 30%).
As of 30 October 2026 · refreshed daily · counts move as websites, DNS and career sites are re-read.
The website-and-DNS footprint is not comparable between a marketing suite and a CRM: Karma's script and mail records show on hundreds of thousands of small sites, React Testing Library rarely leaves a trace outside its own apps. Compare on the job-posting numbers; use the footprint for reach.
- Karma: 2–200 employees
- 46%
- React Testing Library: 2–200 employees
- 57%
- Karma: 1,000+ employees
- 30%
- React Testing Library: 1,000+ employees
- 20%
- Postings per company, 90 days
- 2.6 · 2.1
- Website or DNS footprint
- 0 · 0
Who chooses which
Share of each tool's companies in every segment. "Leans" marks a gap of more than two points.
| Segment | Karma | share | React Testing Library | share | Leans |
|---|---|---|---|---|---|
| Self-employed | 4 | 2% | 5 | 1% | even |
| 2-10 employees | 12 | 5% | 41 | 12% | React Testing Library |
| 11-50 employees | 52 | 21% | 75 | 22% | even |
| 51-200 employees | 50 | 20% | 75 | 22% | React Testing Library |
| 201-500 employees | 37 | 15% | 48 | 14% | even |
| 501-1000 employees | 19 | 8% | 23 | 7% | even |
| 1001-5000 employees | 43 | 17% | 41 | 12% | Karma |
| 5001-10000 employees | 9 | 4% | 7 | 2% | even |
| 10,001+ employees | 22 | 9% | 20 | 6% | Karma |
| Segment | Karma | share | React Testing Library | share | Leans |
|---|---|---|---|---|---|
| Technology & software | 144 | 58% | 204 | 61% | React Testing Library |
| Business & finance services | 50 | 20% | 65 | 19% | even |
| Manufacturing & industry | 22 | 9% | 18 | 5% | Karma |
| Media & content | 10 | 4% | 10 | 3% | even |
| Consumer services & leisure | 5 | 2% | 7 | 2% | even |
| Commerce & trade | 4 | 2% | 15 | 4% | React Testing Library |
| Public, community & associations | 2 | 1% | 2 | 1% | even |
| Health care | 2 | 1% | 4 | 1% | even |
| Hospitality & travel | 2 | 1% | 1 | 0% | even |
| Property & construction | 2 | 1% | – | – | outside top 12 |
| Transport, logistics & rental | 2 | 1% | 4 | 1% | even |
| Utilities & infrastructure | 2 | 1% | 3 | 1% | even |
| Automotive | – | – | 2 | 1% | outside top 12 |
| Segment | Karma | share | React Testing Library | share | Leans |
|---|---|---|---|---|---|
| United States | 134 | 54% | 192 | 57% | React Testing Library |
| United Kingdom | 19 | 8% | 35 | 10% | React Testing Library |
| Germany | 15 | 6% | 10 | 3% | Karma |
| India | 15 | 6% | 22 | 7% | even |
| France | 12 | 5% | 8 | 2% | Karma |
| Spain | 7 | 3% | – | – | outside top 12 |
| Brazil | 4 | 2% | 3 | 1% | even |
| Canada | 4 | 2% | 9 | 3% | even |
| Italy | 4 | 2% | – | – | outside top 12 |
| Romania | 4 | 2% | – | – | outside top 12 |
| Australia | 3 | 1% | 5 | 1% | even |
| Mexico | 3 | 1% | – | – | outside top 12 |
| Poland | – | – | 5 | 1% | outside top 12 |
| Singapore | – | – | 5 | 1% | outside top 12 |
| Lithuania | – | – | 4 | 1% | outside top 12 |
| United Arab Emirates | – | – | 3 | 1% | outside top 12 |
| Segment | Karma | share | React Testing Library | share | Leans |
|---|---|---|---|---|---|
| Software engineering | 837 | 82% | 891 | 94% | React Testing Library |
| Sales | 43 | 4% | 1 | 0% | Karma |
| General management & consulting | 23 | 2% | – | – | outside top 12 |
| Design & UX | 15 | 1% | 1 | 0% | even |
| IT operations & business systems | 9 | 1% | 8 | 1% | even |
| Marketing & communications | 9 | 1% | – | – | outside top 12 |
| Retail & store operations | 8 | 1% | – | – | outside top 12 |
| Customer service & success | 6 | 1% | 2 | 0% | even |
| Data & AI | 5 | 0% | 4 | 0% | even |
| Arts media and entertainment | 2 | 0% | – | – | outside top 12 |
| Business development & strategy | 2 | 0% | – | – | outside top 12 |
| Engineering (non-software) | 2 | 0% | 9 | 1% | even |
| Quality, safety & environment | – | – | 1 | 0% | outside top 12 |
| Unclassified | – | – | 1 | 0% | outside top 12 |
The companies behind each column
Companies using Karma →
Companies using React Testing Library →
unit testing frameworks ranked →
Quote the sentence with the date and the link. The numbers change daily; the link always shows the current ones.
React Testing Library is named by 335 companies in job postings and Karma by 248; 0 name both. (Breaknorm, 30 October 2026, https://breaknorm.co/compare/karma-test-runner-vs-react-testing-library)
Read from the source, not self-reported
Every number on this page can be traced to a page we crawled or a posting we read. Full methodology →
- Job postingsRead hourly from career sites. A tool counts when the employer's own text names it as the team's system; both tools can count for one company.
- Website and DNSScripts and embeds on the company's pages, plus SPF, DKIM, MX and CNAME records of its domain that point at the vendor.
- SegmentsCountry, size and industry from the company profile built from its website.
- Not a reviewNo ratings, prices or feature claims. For those, read the vendors.
Karma vs React Testing Library: questions
Which is more used, Karma or React Testing Library?
By companies naming it in their own job postings, React Testing Library (335) over Karma (248). By website-and-DNS footprint, React Testing Library (0 vs 0), because its scripts and mail records sit on many small company sites.
Who chooses Karma?
46% of Karma companies have 2 to 200 employees, against 57% for React Testing Library. 30% of Karma companies have over 1,000 employees, against 20% for React Testing Library.
Do companies run both?
0 companies name both in their postings, usually Karma in marketing and React Testing Library in sales, or during a migration.
Where do these numbers come from?
From the employer's own text in job postings read hourly from career sites, and from scripts found on company websites in our crawl. No vendor data, no surveys.
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