Working at Tessian |

Tessian Overview

London, England
51 to 200 employees
Company - Private
Computer Hardware & Software
£5 to £10 million (GBP) per year
Tessian is a human layer security platform to automatically prevent cybersecurity threats like spear phishing, misaddressed emails, unauthorized emails (data loss) and non-compliance.

We’re a team of mathematicians, data scientists ... Read more

Mission: Tessian’s mission is to keep the world’s most sensitive data and systems private and

We’re building the world’s first Human Layer Security (HLS) platform to fulfil this ... Read more

Company Updates

  • Check out our new Working at Tessian video!

  • We’ve just announced our raise of $42m in Series B funding led by Sequoia, & partner Matt Miller is joining the board!

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Tessian – Why Work For Us?

At Tessian, we believe in building teams of high performing, brilliant individuals that make work a great and enjoyable place to be! We empower our employees to achieve and develop, giving them the responsibilities, scope and opportunities  that allow them to step up as soon as they're ready to progress. In a fast-growing company where everyone has substantial and visible impact, career advancement is limitless.

We strive to be bold and courageous, and we encourage one another to achieve, bringing passion and dedication to our work that is amplified by the support of our peers and management within Tessian. Does the idea of working with dynamic, smart colleagues and doing your life's best work excite you? Then you're a great fit for Tessian and we'd love to hear from you! You can see all our open roles here.

You can read all about our 2018 internship program here

At Tessian, achieving excellence is central to our company philosophy; founded by Imperial College Engineering graduates, we’re proud to have built a fantastic team of high achievers.

Our employees have demonstrated excellence throughout their lives, whether it’s a preponderance of As & A*s at GCSE and A-Level, degrees from top UK Universities, extra-curricular or academic awards, or coming to Tessian from successful tenures in high-flying careers such as Law and Banking, we’re proud to champion their brilliance.

You can read some blogs from our 2018 Intern Cohort here:

We believe that brilliance starts early.

Which is why, each year, we bring in undergraduates & school leavers we believe are part of the next generation of rising stars.

Our program will give them intensive multi-month internships, with participants taking up roles across all the areas of the business, from data science, to engineering, to sales, marketing, and operations. Each division will have their interns run significant projects and give them a real taste of working life at a high-growth start-up.

Pre-register for our 2019 Summer internship program here

Diversity and Equality are incredibly important to Tessian

We believe in creating a diverse environment for people from all backgrounds and walks of life, and we believe it's not enough to passively commit to such an endeavour, but that it's vital that we actively work to ensure we create a supportive and diverse environment for all our employees.

You can read our equality and diversity statement here. We're also a corporate member of the WISE Campaign for gender equality in STEM subjects and our Chief of Staff, Sabrina Castiglione is on the WISE Young Women's Board.

At Tessian we're also proud to promote and give a platform to all our incredible female employees, who lead departments (including our Heads of Operations, Legal and Compliance, and Inside Sales) and span divisions from Commercial to DevOps, to Backend Engineering to QA.

STEM - which includes our industry, Technology - is an industry in which we're keep to promote diversity, & speaking about our inaugural 2018 Internship Program, Sabrina stated 

it’s very important that leaders in STEM industries do what they can to promote careers in STEM, both in terms of diversity and in numbers. Often people turn away from STEM during educational years and struggle to return later, to what are some of the most rewarding and well-paid careers available. The turn-from-STEM is sadly a trend that disproportionately affects women, which is why I’m proud that at Tessian, we’ve achieved a roughly equal gender split for our inaugural internships, including across the engineering and data science disciplines”.

We're also proud to host an incredibly international team, supporting visa sponsorship, relocation and resettling support, and the brilliant and varied worldviews our globe-trotting colleagues bring us; We strive to build an international company, so it's important to us that we build a team that understand global perspectives.

Gender, race, and nationality are only 3 of the many areas (including religion and belief, sexual orientation, maternity and disability amongst others) in which we're commited to promoting equality and diversity, and we strive to both be the best that we can be, and set an example for the industry.

Tessian announces £9m Series A with Balderton Capital and Accel Partners

We’ve raised of £9m ($13m) in a Series A round led by Balderton Capital and Accel Partners. Last year our business grew 400% and our team expanded from 13 to 50 people; we have ambitious growth plans for the next year, spanning all areas including our product offerings and our sales & marketing divisions. We’re excited about where this next phase of our growth will take us - we hope you are too, so we encourage you to apply today to be part of the next leg of the Tessian journey.

Suranga Chandratillake wrote an article about Balderton's investment: The Challenge of Securing Humans (or ‘Why Balderton just led the Series A in Tessian’)

“What Tessian have done – and this is why we are so excited about them – is apply machine intelligence to understand how humans communicate with each other and use that deeper understanding to secure enterprise email networks,” says Balderton Capital Partner Suranga Chandratillake. “The genius of this approach is that while the product focus today is on email – by far the most used communication channel in the corporate enterprise – their technology can be applied to all communication channels in time. And, as we all communicate in larger volumes and on more channels, that represents a vast opportunity.”

As part of the investment, Balderton Partner Suranga Chandratillake and Accel Partner Luciana Lixandru join the board. She says, “The effectiveness of Tessian’s product attracted our attention at an early stage. Since our seed investment just over a year ago, the company’s ability to address a fundamental data security risk has been reflected in its strong growth and a string of blue chip client wins. I’m excited to be working even more closely with the team, as it rolls out its solution to an even greater number of businesses.”

Tessian Reviews

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Tim Sadler
23 Ratings

    • Work/Life Balance
    • Culture & Values
    • Career Opportunities
    • Comp & Benefits
    • Senior Management
    Current Employee - Outbound Growth Associate in London, England
    Current Employee - Outbound Growth Associate in London, England
    Positive Outlook
    Approves of CEO

    I have been working at Tessian full-time (Less than a year)


    Great autonomy
    Fully stocked kitchen
    Regular socials
    Get to work with incredibly intelligent people every day


    Occasionally disorganised but as is the case with a rapidly scaling start up

    Advice to Management

    Keep up the good work! maintain culture as you scale.

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Tessian Photos

Tessian photo of: Team on the roof terrace!
Tessian photo of: Founders - Tim, Ed and Tom
Tessian photo of: Senior Management (L to R) Ed, Tim, Henry, Andy, Tom, Sabrina, Abhirukt
Tessian photo of: Senior Management (L to R) Henry, Ed, Sabrina, Andy, Tim, Abhirukt, Tom
Tessian photo of: Engineering
Tessian photo of: Tessian Team!
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Tessian Interviews



Getting an Interview

Getting an Interview




  1. Featured Interview

    Helpful (6)  

    Backend Engineer Interview

    Anonymous Employee in London, England
    Accepted Offer
    Positive Experience
    Difficult Interview


    I applied online. I interviewed at Tessian (London, England) in January 2017.


    Intro call (non-technical)- Technical Assessment (in my own time, about an hour) - In-depth Call (with a senior member of the team I was applying to) - Face-to-face Interview (mix of senior management and the team I was applying to)

See All 28 Interviews

Tessian Awards & Accolades

  • Overall Enterprise Email Security Solution Provider of the Year, Cyber Security Breakthrough, 2017
  • Best Innovation in Data Protection and Privacy, CogX, 2017
  • Most Innovative Cyber Security Company, INFOSEC, 2017
  • Global Excellence Award for Best Security Startup, Info Security Product Guide, 2017
  • Best Machine Intelligence StartUp, Legal Geek, 2016
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