Application Security Engineer

Fyxer AI; London; On-site; GBP 125,000 - 150,000; Full time

Job summary

A cutting-edge AI company in London seeks an Application Security Engineer. The role involves designing security controls and ensuring a security-first culture. Candidates must have over 4 years of cybersecurity experience and knowledge of key frameworks and tools. The package includes a salary of £80k+ and meaningful equity, with a strong potential for career growth in a fast-paced environment.

Benefits

Private medical insurance

Equity options

Qualifications

• 4+ years in cybersecurity or technical security roles required.
• Experience with at least one cloud provider (AWS/Azure/GCP).
• Scripting experience required (Python, Bash, PowerShell).

Responsibilities

• Design and implement security controls.
• Harden cloud environments and monitor endpoints.
• Analyze logs and detect anomalies.

Skills

Cybersecurity experience

NIST, ISO 27001, or CIS Controls familiarity

Networking knowledge

OS (Windows/macOS) knowledge

Log analysis skills

Tools

Splunk

CrowdStrike

Nessus

Palo Alto

Wireshark

Job description

Who we are

At Fyxer, we're building something bold: an AI Executive Assistant that genuinely takes work off your plate. Imagine opening your laptop and finding your emails written, your meetings scheduled, your follow-ups sent, and your inbox under control all without you lifting a finger. That's what we do. We're not a SaaS product with a bolt-on chatbot. We're a pure-play AI company using cutting-edge techniques (think fine-tuned open source models, retrieval augmented generation, intelligent tool use) to actually automate real work, not just create more of it.

And it works:

• Launched March 2024
• $1M→ $16M revenue since January 2025
• 1,000s of paying users
• Built by a team of just 4

We're growing fast and we're looking for someone exceptional to own and scale our security efforts from the inside.

What you'll be working on

We're looking for a hands-on Application Security Engineer with at least 4 years of real-world experience to help us build a security-first culture and infrastructure as we scale. You'll be our first dedicated security hire, working directly with our CISO and engineering teams to embed best practices, monitor for threats, and stay ahead of attackers.

This isn't a passive, checkbox-ticking role. You'll get to:

• Design and implement controls from the ground up
• Harden cloud environments and monitor endpoints
• Run threat hunts, analyze logs, and detect anomalies
• Respond to incidents in real-time, not just read about them
• Participate in tabletop exercises and incident simulations
• Stay close to the latest tactics, techniques & procedures (TTPs)

Your fingerprints will be on every layer of our infrastructure from CI/CD pipelines to employee devices to cloud configurations.

Qualifications

You'll thrive here if you have:

• 4+ years in cybersecurity or technical security roles
• Familiarity with frameworks like NIST, ISO 27001, or CIS Controls
• Working knowledge of networking, OS (Windows/macOS), and security protocols
• Experience with tools like Splunk, CrowdStrike, Nessus, Palo Alto, Wireshark
• Basic cloud security knowledge (AWS/Azure/GCP)
• Scripting experience (Python, Bash, PowerShell)
• Experience/Knowledge within a JS tech stack is a must.
• A sharp eye for log analysis, threat investigation & incident response
• Bonus: Security+ / CEH / CySA+ certs

A bit about you

You're deeply curious, action-oriented, and thoughtful under pressure. You don't just want to spot problems, you want to fix them, automate the fix, and then teach the team how to prevent it altogether.

You want ownership, not hand-holding. You thrive in ambiguity and get a kick out of being the person others rely on when things go sideways.

What you'll get from us

£80k+ salary and meaningful equity and private medical insurance as part of the package.

The role is onsite at our office in Holborn/Chancery Lane in central London at least 4 days a week as we scale.

Why Fyxer?

We're not building another dashboard. We're creating a new category of AI productivity tools, one that changes how people actually work.

We keep our team intentionally small, because we believe a handful of mission-driven people can outperform bloated orgs with 10x the headcount. That means:

• You'll move fast
• You'll own big decisions early

We're gunning for $30+M in ARR by the end of 2025, and there will be real opportunities for you to grow career wise as we scale.

How we hire

• Submit your CV (no need for a cover letter)
• Quick intro call (20 min) with our talent team
• Hiring manager interview (30 min)
• Real-world case study (45 min)
• Meet the team over lunch (60 min)