Series A SaaS companies in London

Prolific is a technology company building the biggest pool of quality human data in the world—and the ultimate platform to access it.Over 35,000 AI developers, researchers, and organizations use Prolific to gather data from real, engaged participants—with a new study launched every 2 minutes.Prolific has been ranked among the fastest-growing businesses in the Financial Times 1000 in 2025 & 2024 and the Deloitte Technology Fast 50 in 2023.

• Series A
• 1.5k employees
• Founded 2014

Connectd is a people-first platform connecting startups and scaleups with experienced fractional executives, strategic advisors and directors. Using AI-powered insights and smart matching technology, we ensure the right experts are placed with the right companies, so both sides can grow with confidence. In a world shaped by transformative technology, we provide a human-centred ecosystem where companies access the guidance they need to scale, and senior leaders find meaningful, flexible work that puts their experience to powerful use.Since 2019, Connectd has facilitated over 50,000 connections across the UK and US, helping both sides of the ecosystem succeed: startups and scaleups gain trusted leadership at pivotal moments, and senior leaders and executives build dynamic, rewarding fractional careers.

• Series A
• 622 employees
• Founded 2019

Delivering high-quality construction projects on time and within budget has never been more complex. With demand showing no sign of slowing down, mitigating risks, avoiding unnecessary costs, and streamlining processes is more important than ever.XYZ Reality is here to help you navigate these complexities. Through real-time project controls and engineering grade augmented realityTM, XYZ Reality empowers teams with unmatched precision and visibility, enabling proactive issue resolution and accelerating project delivery. With real-time, objective field data, teams can effortlessly track on-site progress and quality, helping prevent delays and ensuring projects are delivered on time. Leading developers partnering with XYZ Reality experience faster timelines, reduced construction costs, and enhanced quality assurance. With over $12 billion in mission-critical projects successfully managed, XYZ Reality has helped developers reduce risks, cut costs, and reach the market faster with confidence. At the forefront of construction innovation, XYZ Reality enables companies to drive faster revenue generation, improve sustainability, and deliver exceptional project quality. Learn more at www.xyzreality.com.

• Series A
• 390 employees
• Founded 2017

Beam is a social enterprise bringing AI to welfare services, trusted by over 300 partners globally. Enabled by tech and AI, our expert caseworkers have supported thousands of underserved people into homes and jobs, while our software has slashed admin for over 100,000 of frontline workers.Funded by the Mayor of London and the world's top tech entrepreneurs, Beam is transforming how the world supports those left behind. Beam’s award-winning work has been covered widely in the media, including by the BBC, The Times, The FT, The Independent, Evening Standard, Sky, Time Out and others. Beam were also named one of London’s Top 10 Startups by WIRED magazine, Top 15 UK Startups by LinkedIn, and feature regularly on The Escape 100.

• Series A
• 346 employees
• Founded 2017

Threecolts is redefining business by acquiring and bundling software, offering marketplace and retail operations capabilities at a lower price.Tens of thousands of customers—including some of the fastest growing brands, Fortune 500 enterprises, and global agencies—are using Threecolts to grow faster, lower costs, and become more agile.

• Series A
• 331 employees
• Founded 2021