Senior Security Engineer: Build Secure Go Services on AWS

numi; Greater London; On-site; GBP 90,000 - 150,000; Full time

Job summary

numi Partners is seeking a senior software engineer with deep security expertise to ship production code (Go, Postgres, React) on AWS. You will embed security in design, drive threat modelling, and own the security of the AWS estate in a small, high-stakes team.

You will lead incident response, support client security workloads, and raise security literacy across the engineering group, while working in a domain with high-value transactions.

Qualifications

• Five or more years as a software engineer with security-focused work.
• Strong backend development experience; Go preferred.
• Hands-on AWS production security experience.
• Threat modeling as a disciplined practice.
• Experience with databases and web app security.
• Frontend React knowledge is a plus.
• Experience in domains with high-value transactions.
• Ability to operate in a small team with security depth.
• Experience supporting SOC 2 Type II / ISO27001 or government frameworks.
• Postgres schema design, RLS, and audit-heavy workloads.

Responsibilities

• Design, review, and ship production Go and React code.
• Lead threat modelling for new features and changes.
• Own security of the AWS estate: IAM, segmentation, secrets.
• Embed security into CI/CD: SAST, DAST, dependencies.
• Build security features: audit integrity, access controls, data isolation.
• Lead incident response: detection, investigation, remediation.
• Support client-facing security work and questionnaires.
• Raise security literacy through design reviews and pairing.
• Operate as the security depth in a small team.

Skills

Go

AWS

React

PostgreSQL

Threat modelling

Incident response

CI/CD security

IAM design

Network segmentation

Secrets management

Data isolation

Auditing

SOC 2 / ISO27001

Job description

numi Partners is seeking a senior software engineer with deep security expertise to ship production code (Go, Postgres, React) on AWS. You will embed security in design, drive threat modelling, and own the security of the AWS estate in a small, high-stakes team.

You will lead incident response, support client security workloads, and raise security literacy across the engineering group, while working in a domain with high-value transactions.