Senior Software Engineer - Security

ZipRecruiter; Greater London; Hybrid; GBP 102,000 - 120,000; Full time

Job summary

A dynamic B2B SaaS company in London is seeking a Senior Software Engineer – Security to take ownership of building security features and shaping the security vision. This high-impact role requires strong cloud-SaaS engineering experience, deep AWS expertise, and a proactive approach to security. Join a fast-growing platform offering excellent equity opportunities and a chance to work in a modern tech environment.

Benefits

Equity with meaningful upside

High-impact role

Dynamic work environment

Qualifications

• Strong experience with cloud-SaaS engineering focusing on security.
• Deep expertise in AWS and serverless technologies.
• Proven track record of proactive security feature implementation.

Responsibilities

• Shape and drive the security vision for the platform.
• Build new security features and create testing frameworks.
• Ensure security is integrated into software lifecycle.

Skills

Cloud-SaaS engineering experience

AWS & serverless expertise

Designing and rolling out security features

High ownership mindset

Job description

Overview

Job Title: Senior Software Engineer – Security

Salary: Up to £120k + £20k–£50k equity

Location: London (3 office days/week)

Industry: B2B SaaS

Stage: Series A, backed by tier-1 VCs

Why you’ll love this role:

• Founding security engineer role with real ownership over systems
• Modern serverless stack: AWS, TypeScript, IaC
• Equity with meaningful upside
• High-impact opportunity to design security from the ground up

Note: This role does not offer relocation or sponsorship

We’re building a fast-growing SaaS platform that’s redefining how businesses buy. As our first dedicated security engineer, you’ll shape the security vision, drive implementation, and ensure security is an enabler for growth not a blocker.

You’ll be fully embedded in the platform engineering team, building new security features, creating testing frameworks, and hardening our serverless AWS infrastructure. Security is built in from day one, so you’ll be designing, implementing, and evolving systems that stay ahead of emerging threats.

About 10–15% of your time will be spent helping enterprise clients understand architecture, frameworks, and secure connections, while demonstrating how security is integrated into our software lifecycle.

This is a high-ownership role for someone passionate about engineering, delivery, and meaningful impact. You’ll build the security function, influence engineering culture, and scale security as the company grows.

What we’re looking for

• Strong cloud- SaaS engineering experience with a security focus
• Deep AWS & serverless expertise (IAM, networking, KMS, hardening)
• Proven track record of designing and rolling out security features proactively
• High ownership mindset, bias for action, and passion for building secure, scalable systems