Top Series A companies in London

Companies that have closed a Series A — product-market fit confirmed and scaling. Filtered to companies headquartered in London.

Built from a search like: “Top Series A companies in London”

Ranked by current headcount across Series A companies headquartered in London. Refreshed daily.

1
Sky· Isleworth, England, United Kingdom
- Series A
- 35.3k employees
- Founded 1989
2
Google DeepMind· London, England, United Kingdom
- Series A
- 8.3k employees
- Founded 2010
3
Zenith· London, England, United Kingdom
- Series A
- 5.4k employees
- Founded 1988
4
Jellyfish· London, England, United Kingdom
- Series A
- 2.3k employees
- Founded 2005
5
We Are Social· London, England, United Kingdom
- Series A
- 1.9k employees
- Founded 2008
6
The Times and Sunday Times· London, England, United Kingdom
- Series A
- 1.6k employees
- Founded 2020
7
Influencer· London, England, United Kingdom
- Series A
- 1.3k employees
- Founded 2015
8
Prolific· Greater London, England, United Kingdom
- Series A
- 987 employees
- Founded 2014
9
Koru Kids· London, England, United Kingdom
- Series A
- 734 employees
- Founded 2017
10
Eagle Eye· London, England, United Kingdom
- Series A
- 668 employees
- Founded 2003
11
The Smart Cube· London, England, United Kingdom
- Series A
- 650 employees
- Founded 2003
12
eMed Healthcare UK· London, England, United Kingdom
- Series A
- 594 employees
- Founded 2013
13
Hydrogen Group· London, England, United Kingdom
- Series A
- 554 employees
- Founded 1997
14
PIB Insurance Brokers· London, England, United Kingdom
- Series A
- 543 employees
- Founded 2014
15
proSapient· London, England, United Kingdom
- Series A
- 510 employees
- Founded 2017
16
nShift· London, England, United Kingdom
- Series A
- 435 employees
- Founded 2021
17
Ben· London, England, United Kingdom
- Series A
- 409 employees
- Founded 2019
18
R3· London, England, United Kingdom
- Series A
- 379 employees
- Founded 2015
19
PDD· London, England, United Kingdom
- Series A
- 362 employees
- Founded 1980
20
XYZ Reality· London, England, United Kingdom
- Series A
- 354 employees
- Founded 2017
21
Threecolts· London, England, United Kingdom
- Series A
- 349 employees
- Founded 2021
22
ME+EM Ltd· London, England, United Kingdom
- Series A
- 348 employees
- Founded 2009
23
Isomorphic Labs· London, England, United Kingdom
- Series A
- 348 employees
- Founded 2021
24
ZAVA· London, England, United Kingdom
- Series A
- 342 employees
- Founded 2011
25
Beam· London, England, United Kingdom
- Series A
- 325 employees
- Founded 2017

Find engineers at Series A companies in London

Series A companies in London are some of the fastest-moving employers in the market. The list above ranks the largest Series A-stage companies headquartered in London by current headcount, drawn from public LinkedIn and Crunchbase records. With 721 matching companies in our index, the density of senior engineers, designers, and founders is unusually high.

At Series A, teams tend to be small, ambitious, and on the hunt for senior talent. The companies on this list are good signals for where the Londontalent market is heating up — and for which engineers and founders are about to become tomorrow’s operators.

Refolk converts this list into a live search. Ask for “founders of Series A companies in London” or “senior engineers at Series A companies in London hiring” and Refolk returns a ranked shortlist with evidence behind each match.

How this list is built

Refolk pulled Series A companies headquartered in London from public LinkedIn and Crunchbase records, ranked them by current employee count, and kept those with at least 5 employees. The list refreshes once a day.

Last refreshed: Thu, 07 May 2026 07:47:57 GMT

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