Security Engineer

Flagstone; City Of London; On-site; GBP 50,000 - 70,000; Full time

Job summary

A financial technology firm in London is seeking an experienced Security Engineer to enhance cloud security processes in Azure. The ideal candidate will have 3–5 years in security roles, a strong understanding of cybersecurity, and experience with automation tools. This opportunity offers a competitive benefits package and a supportive work environment focused on personal development and growth.

Benefits

Competitive bonus scheme

Flexible benefits budget

Private health care

Learning and development budget

Mental wellbeing support

25 days holiday plus bank holidays

Enhanced Parental Leave

Qualifications

• 3-5 years in a security engineering or internal security role.
• Practical understanding of cybersecurity fundamentals.
• Experience with infrastructure-as-code such as Terraform.

Responsibilities

• Improve Azure-based security tooling and incident response.
• Investigate suspicious activity and contribute to cloud hardening.
• Participate in security assessments and support penetration testing.

Skills

Problem-solving skills

Attention to detail

Growth mindset

Tools

Microsoft Sentinel

Defender XDR

Terraform

PowerShell

Job description

What is Flagstone?

Flagstone is many things. An online savings platform, reinventing how individuals, businesses, and charities manage, protect, and grow their cash. A diverse group of people, bound by a collaborative spirit, and shared purpose. And lastly, a thriving, profitable business – where smart people do their best work.

Each definition shares a common thread: our unique culture. It’s our pride and joy. And our competitive advantage.

A feel for our culture:

To revolutionise the savings market, we need to be at our best. But high performance takes more than talent – it takes a culture of kindness, respect, and growth.

That’s why we’re building a diverse, inclusive community, where your voice is heard and valued. Where, with close support and room to develop, you can surpass even your own expectations. And be rewarded for it.

We may not change the world, but can change the world of financial technology. And all it takes is a winning mix of drive, talent, and empathy. Our culture celebrates all three.

What you’ll do:

We’re expanding our security engineering team and looking for someone who enjoys solving practical security problems, learning new tools, and working across a modern Microsoft environment. You’ll help strengthen our detection and response processes, improve cloud security in Azure, and support engineering teams in building safely and responsibly. This is a hands‑on role that covers a mix of operational work and engineering improvements. You don’t need to know everything already - you’ll have opportunities to learn, try new approaches, and pick up experience across different areas of security.

What you’ll work on

• Help to improve and maintain our Azure-based security tooling, including Microsoft Sentinel, Defender XDR, and Defender for Cloud
• Contribute to the optimisation, tuning, and maintenance of SOC tools
• Investigate suspicious activity and support incident response when needed
• Contribute to cloud hardening in areas such as identity, access, networking, storage, WAF, and logging
• Participating in security risk assessments, threat modelling and vulnerability management.
• Support penetration testing by organising test execution, reviewing results, and helping teams prioritise fixes

What we’re looking for

• Around 3–5 years in a security engineering or internal security team role
• Practical understanding of cybersecurity fundamentals and common risks
• Experience with infrastructure-as-code (Bicep, Terraform, or similar)
• Familiarity with PowerShell for automation or general scripting tasks
• Good problem-solving skills and attention to detail
• Able to work in a fast-moving environment with competing priorities
• Some knowledge of frameworks like SOC 2, ISO 27001, GDPR, or NIST CSF
• A growth mindset and curiosity to keep learning

How we reward you:

At Flagstone, the benefits extend beyond false gifts like “fruit and snacks”. Instead, we invest in your health, wealth, and professional development. Here’s a selection of our benefits:

• Competitive bonus scheme - designed to reward and recognise high performance
• Flexible benefits budget - a pot to fund meaningful benefits for you, whether it's hormone or fertility testing, cancer screening, neuro‑diversity coaching or something that matters for you.
• A range of salary sacrifice options to help you make tax efficient savings on electric cars, nursery schemes, home and tech goods.
• Around the World scheme - 3 months work from anywhere scheme
• Mental wellbeing support – Access therapy and mental health sessions through Spill
• Learning and development – £1,000 personal development budget to help you grow in your role.
• Private health care - Enjoy all the benefits AXA has to offer, including reduced gym memberships and medical history disregarded
• Medical cash plan - To help you with the costs of dental and optical expenses
• Life insurance and Income Protection- four times your annual salary for peace of mind
• Matched pension contributions up to 5%
• 25 days holiday - plus bank holidays, well‑being days and volunteering days
• Enhanced Parental Leave – enhanced maternity, paternity and adoption pay.

All are welcome.

At Flagstone, we’re assembling a diverse team that defies our industry’s norms. Think this role could suit you? We encourage you to apply, no matter your background.