One Big Circle on cord

One Big Circle

Product Security Engineer

External position
Bristol, UK
Hiring internally for One Big Circle?
Machine Learning and AI · Transport
Work Safer and Smarter with AIVR
Posted
a week ago
Checked
cord regularly checks that external positions are still open
20 hours ago

Skills & Experience

Job roles: Security Engineer
Experience level: Senior
Core skills considered: AWS, Python, Linux, Penetration Testing, Security Testing
Other skills considered: Threat Detection, Cloud Security, Embedded, Technical Writing

Logistics

Base salary: £70K - £90K
Employment type: Permanent
Remote working: Hybrid (up to 1 remote day p/w)
Visa sponsorship: Not available

Job Description

We are looking for a senior, hands-on security engineer to own the security of our AIVR product stack end to end. You will spend your time thinking like an attacker, finding weaknesses in our systems before anyone else does, and then coordinating with the engineering teams to remediate.

You will pull the architecture apart, work out the realistic attack paths, test them, prove what's exploitable, explain the impact to the engineers who own them, help them work out a sensible fix, and then verify the fix.

This is a technical role in a team that likes getting things done. It is not a compliance or GRC position.

Your job is to make the product secure by continuously scouting for vulnerabilities and red teaming the AIVR product.


What You'll Be Securing

  • Edge devices on trains. Embedded Linux devices with cameras and other sensors, fitted to in-service rolling stock. They are remote, physically outside our control, and connect back to us over 4G/5G.
  • AWS cloud platform. A comprehensive and complex data processing platform, including serverless and containerised services developed predominantly in Python and hosting 7+ PB of data.
  • Web applications. The AIVR web applications used across the rail industry, with multi-tenant workspaces, sharing tools and integrations.
  • Machine learning infrastructure. Training and inference workloads running in a 3rd party datacentre.

Responsibilities

  • Continuously red team our product stack: threat modelling, penetration testing, code and configuration review, and adversarial thinking applied across devices, cloud, applications and ML infrastructure.
  • Highlight findings and their impact. Work with the team that owns the system to explain findings and validate fixes.
  • Input into AWS security architecture with the Platform team: IAM, organisation and account structure, networking, encryption, logging and detection.
  • Evaluate device-side security with the Device team: secure boot and update signing, credential and certificate lifecycle, remote access, tamper and theft scenarios.
  • Harden the software supply chain: dependency and container vulnerability management, SBOMs, CI/CD pipeline integrity, and CVE exposure.
  • Build security into the way we ship: static and dynamic analysis, IaC and container scanning, secrets detection, and secure coding guidance that engineers will actually use.
  • Improve detection and response: make sure the right things are logged and alerted on and contribute hands-on when there is an incident. Incident response here is an all-hands affair; depending on the incident you may lead it or support whoever does.
  • Scope, run and challenge third party penetration tests, and triage reports that arrive through our vulnerability disclosure policy.
  • Document what you find and what you change in clear technical writing that engineers can act on and that feeds naturally into our ISO 27001 evidence and customer security assurance, without you having to run that process.
  • Raise the bar across the team through code review, threat modelling sessions and mentoring, so that security knowledge spreads rather than bottlenecking on you.

We want someone who is comfortable ranging across cloud, embedded, web and infrastructure in a single week. Nobody will have depth in every area below; we would rather have real depth in two or three and the curiosity to pick up the rest.


Essentials

  • Substantial hands-on security engineering experience (five or more years) in teams that ship software, with a strong offensive mindset.
  • Real software engineering ability. Comfortable in Python, and able to read and reason about C/C++ and JavaScript/TypeScript.
  • Deep, practical AWS security knowledge: IAM and Organizations, S3, VPC networking, CloudTrail, and infrastructure as code.
  • Strong Linux fundamentals, on both servers and embedded devices.
  • The ability to explain risk to developers, prioritise pragmatically, and be persistent when it matters.

Capability Areas

These describe the kinds of problems you will work on.


Cloud & Platform Security: AWS IAM design and review, permissions, SSO, credentials, secrets management, account segmentation, VPC and network controls, S3 data protection at scale, WAF, container and serverless security, infrastructure as code, CI/CD security, ransomware resilience and recovery testing.


Edge Device & Embedded Security: Embedded Linux hardening (Yocto or similar), secure boot, over-the-air updates, disk encryption, device identity and PKI, certificate lifecycle, VPN and remote access design, cellular connectivity, edge API security, physical attack and tamper scenarios, firmware analysis, OT security principles, secure device provisioning and decommissioning.


Application Security: OWASP Top 10 and beyond, authentication and session management, authorisation and multi-tenant isolation, API security, share link and token design, secure code review, browser security controls, SSO/OIDC integration.


Supply Chain & ML Infrastructure: Dependency and container vulnerability management, SBOM generation and tracking, CVE triage and prioritisation, artifact signing and provenance, pipeline integrity, datacentre network segmentation, ML framework exposure, data flows between datacentre and cloud.


Detection & Response: Logging strategy, alerting and SIEM concepts, threat hunting, incident response, forensics fundamentals, tabletop exercises, backup and recovery testing.


Nice to Have

  • Certifications such as OSCP, OSWE, CRTO or AWS Certified Security Specialty are welcome, but we care far more about demonstrable work than certifications.
  • Experience in rail, transport, utilities or other national infrastructure, and familiarity with the NCSC Cyber Assessment Framework, NIS regulations, ISO 27001 or IEC 62443.
  • Public evidence of your craft: CVEs, write-ups, open source tooling, bug bounty history or conference talks.

Personal Attributes

  • Curious and persistent: you enjoy working out how something can be made to misbehave.
  • Practical and delivery-focused, balancing security rigour with the reality of a relatively small team shipping frequent product updates.
  • Direct and constructive: you can tell an engineer their design is broken in a way that makes them want to fix it with you.
  • Self-motivated, comfortable owning an area without close supervision, and happy to flex across responsibilities in a growing company.
  • Strong written communication, able to produce findings and documentation that stand on their own.

Company Benefits

  • Life Assurance
  • Pension Scheme
  • 25 Days Holiday plus bank holidays
  • Private Healthcare Cover
  • Share Options
  • Work-related training courses
  • Complimentary snacks and refreshments including fresh fruit
  • Access to Bike to Work Scheme
  • Secure bike storage and shower facilities
  • Social Events
Product Security Engineer at One Big Circle
Position posted a week ago

Talk directly
to who's hiring

cord intros you to the companies worth joining, from seed to enterprise.

Everything you need to find work

Surface every relevant position, direct message the people hiring and manage all your applications in one place.

Get started

Every position in one place

We index the web for open positions that might be relevant to you and bring them all in one place.

Positions you might like split into tabs based on their type

Direct messaging

No more CV blackholes. Message people hiring directly and see their activity live on cord.

A sent message to a hiring manager
A board of positions in different stages

Application management

Manage all your applications and interviews in one place.

Advanced insights

Know your worth and see how you compare with other applicants.

Visualisation of a profile match score for a position and score comparison with other applicants

Direct.
Transparent.
Human.

On cord you can message people hiring directly, see when they were last active, how responsive they are and access transparent information that you wouldn't be able to find anywhere else.

Photos people at Starling BankPhotos people at Starling BankPhotos people at Starling BankPhotos people at Starling BankPhotos people at Starling Bank
Starling Bank on cord

Starling Bank

Full Stack Engineer (ML Ops)

London, UK
FinTech · Banking · Finance
A better bank for everyone
Active
over 6 months ago
Responds to
0% of requests
Responds in
1h 55m
Requests
7 pending

Skills & Experience

Job roles: Full Stack
Experience level: Mid, Senior
Core skills considered: Java, React, Redux, AWS, JavaScript

Logistics

Base salary: £70K - £110K
Employment type: Permanent
Remote working: Hybrid (up to 2 remote days p/w)
Visa sponsorship: Not available

Job Description

Starling is the UK’s first and leading digital bank on a mission to fix banking! Our vision is fast technology, fair service, and honest values. All at the tap of a phone, all the time.

Starling is the UK’s first and leading digital bank on a mission to fix banking! We built a new kind of bank because we knew technology had the power to help people save, spend and manage their money in a new and transformative way.

We’re a fully licensed UK bank with the culture and spirit of a fast-moving, disruptive tech company. We’re a bank, but better: fairer, easier to use and designed to demystify money for everyone. We employ more than 3,000 people across our London, Southampton, Cardiff and Manchester offices.

Our technologists are at the very heart of Starling and enjoy working in a fast-paced environment that is all about building things, creating new stuff, and disruptive technology that keeps us on the cutting edge of fintech. We operate a flat structure to empower you to make decisions regardless of what your primary responsibilities may be, innovation and collaboration will be at the core of everything you do. Help is never far away in our open culture, you will find support in your team and from across the business, we are in this together!

The way to thrive and shine within Starling is to be a self-driven individual and be able to take full ownership of everything around you: From building things, designing, discovering, to sharing knowledge with your colleagues and making sure all processes are efficient and productive to deliver the best possible results for our customers. Our purpose is underpinned by five Starling values: Listen, Keep It Simple, Do The Right Thing, Own It, and Aim For Greatness.

Hybrid Working

We have a Hybrid approach to working here at Starling - our preference is that you're located within a commutable distance of one of our offices so that we're able to interact and collaborate in person. We don't like to mandate how much you visit the office and work from home, that's to be agreed upon between you and your manager.

Our Data Environment

Our Data teams are excited about the value of data within the business, powers our product decisions to improve things for our customers and enhance effective and agile decision making, regardless of what their primary tech stack may be. Hear from the team in our latest blogs or our case studies with Women in Tech.

We are looking for talented data professionals at all levels to join the team. We value people being engaged and caring about customers, caring about the code they write and the contribution they make to Starling. People with a broad ability to apply themselves to a multitude of problems and challenges, who can work across teams do great things here at Starling, to continue changing banking for good.

Requirements

We have built our entire banking platform in house and mostly in Java. We are looking for people who want to work on building the tooling that is used by our engineers on a daily basis.

We are looking for people who are truly full stack, and are as comfortable polishing their javascript front end as they are debugging the innards of their java applications database interactions, or standing up infrastructure with terraform. We are looking for people who can:

  • Design REST apis.
  • Code backend services, ideally using Java, or another other server side compiled language.
  • Develop modern front ends, ideally using React and Redux.
  • Get their code into the cloud and support it there, ideally on AWS.
  • Believe in clean coding, simple solutions, automated testing and continuous deployment.
  • Like to take ownership of a feature from the original idea through to live.
  • Think (like us) that a small number of empowered developers is the right way to deliver software.

Company Benefits

  • 33 days holiday (including flexible bank holidays)
  • An extra day’s holiday for your birthday
  • 16 hours paid volunteering time a year
  • Part-time and/or flexible hours available for most roles
  • Salary sacrifice, company enhanced pension scheme
  • Life insurance at 4x your salary
  • Hybrid/remote working
  • Private Medical Insurance with VitalityHealth including mental health support and cancer care. Partner benefits include discounts with Waitrose, Mr&Mrs Smith and Peloton
  • Generous family-friendly policies
  • Varied social groups set up and run by our employees
  • Perkbox membership giving access to retail discounts, a wellness platform for physical and mental health, and weekly free and boosted perks
  • Access to initiatives like Cycle to Work, Salary Sacrificed Gym partnerships and Electric Vehicle (EV) leasing

Full details are available on our careers site

Interview Process

Interviewing is a two way process and we want you to have the time and opportunity to get to know us, as much as we are getting to know you! Our interviews are conversational and we want to get the best from you, so come with questions and be curious. In general you can expect the below, following a chat with one of our Talent Team:

  • Stage 1 - 30 mins with one of the team
  • Stage 2 - Take home challenge
  • Stage 3 - 90 mins technical interview with two team members
  • Stage 3 - 45 min final with an executive and a member of the people team
Alex Yeates on cord
Message Alex Yeates at Starling Bank
Typically responds in an hour

What people are saying

2,000+

users joining every week

Oliver on cord

Oliver

Software Engineering Consultant
It's really easy to use, has a solid selection of jobs, and makes it helpful to direct message companies. The platform seems to offer a good range of opportunities while keeping the process simple and convenient.
November, 2025
David on cord

David

Lead Software Engineer
The platform allows you to create a professional CV, making the setup process simple and polished. The internal chat also provides an easy way to directly contact hiring companies, which makes communication much more efficient.
November, 2025
40,000+

open positions

Nicolae on cord

Nicolae

Senior Full Stack Developer
It is a great platform if you are looking for a job. It makes the search process straight forward and gives you access to solid opportunities.
November, 2025
3 million+

messages exchanged so far

Nicolae on cord

Nicolae

Senior Full Stack Developer
It is a great platform if you are looking for a job. It makes the search process straight forward and gives you access to solid opportunities.
November, 2025
83.61%

response rate from companies

Aarambha on cord

Aarambha

Associate Software Engineer
Absolutely amazing idea, the ability to see which recruiters are active makes finding opportunities very quick. There is a form of transparency built into the website that lacks in any other job searching platform.
August, 2025
Adam on cord

Adam

Senior Engineer
cord was great. Clean UI, easy to browse, and the data feature made it a breeze to quickly check whether my profile would match up well with a particular role. The messaging system made it easy to approach companies but also filter out unwanted requests.
August, 2025
4.6

score on Trustpilot

Talk directly to the people that matter

Join the hundred of thousands of people using cord to find work

Get started
 on cord
 on cord
 on cord
 on cord
 on cord
+410 joined last week
Moved to your Not right positions