Intelligent Cloud Email Security

Cyber Security

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Company mission

To keep the world’s most sensitive data and systems private and secure.



HQ Location

Finsbury, London, UK


Few candidates hear
back within 2 weeks

34% female employees

-18% employee growth in 12 months

Otta's take on Tessian

Theo Margolius headshot

Theo Margolius

COO of Otta

While other forms of workplace communication have gained a lot of traction (namely Slack and Microsoft Teams), email still dominates as by far the most popular way for people to communicate at work.

However, sophisticated cyber attacks are becoming more common, with cybercriminals impersonating colleagues, customers or suppliers in targeted attacks that are difficult for people to detect. Tessian’s technology detects when an email represents a threat, reducing the chance of human error.

The problem is real for all company sizes. Hiscox, a big insurer, reported that small businesses in the UK are targeted with 65,000 attacks per day. Those suffering from incidents are facing costs of ~£25k.

There aren't many other companies that have rocketed as much as Tessian in the last couple of years. It started out slow, but has grown rapidly since its $2.7m seed round in 2017 (which was quickly followed by a $13m round in 2018, a $42m round in 2019 and a $65m round in 2021). The company has focused on accelerating expansion across the North American Market and is well set to see continued success in the market.

Total funding - $130.5m

Last 2 fundraises

May 2021



Aug 2021



This company has top investors

Company benefits

  • Company lunches
  • Learning and development
  • Retirement plans
  • Dog friendly office
  • Flexible working
  • Classpass discount

Company values

  • Human First
  • Customer Centricity
  • Positive Mindset. Solution Oriented
  • Grit and Perseverance
  • We Do the Right Thing
  • Craft at Speed


Current Investment Scout at Sequoia Capital. They have served as a Mentor for several companies and programmes. Former Global Banking Analyst at HSBC.

Former Investment Banking Executive at Valence Group and previous worked as an Energy & Resources Corporate Finance Analyst at RBS Global Banking & Markets.

Tom Adams

(Head of Client-side Engineering)

Additionally served as COO of the company along with their current role. Worked as a Mergers & Acquisitions Analyst at UBS and was a Corporate Advisory Analyst at Santander.

People progressing

Emma joined Tessian 3 years ago as a Software Engineer and has since been promoted to Senior Engineer and more recently to Engineering Manager.

James joined Tessian as an SDR in 2018, he then progressed into the Technical Operations Team and become Tessian's first Sales Engineer. James has since been promoted again to Customer Program Manager.

Diversity & Inclusion at Tessian

  • We report on representation and inclusion internally to hold ourselves accountable to creating a more diverse and inclusive company
  • We create entry level programmes to hire and internally develop people from underrepresented backgrounds
  • We commit to transparently communicating our processes around employee experience such as salary benchmarking, promotions, internal moves, and organisational restructuring
  • We build learning & development approaches to accelerate the growth of future leaders from diverse backgrounds

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Tessian is hiring for 4 jobs on Otta!

All locations
Tessian 1Tessian 2Tessian 3