Senior Infrastructure Engineer

Senior Infrastructure Engineer
Remote (UK-based), with occasional on-site work at our data centres | Full-Time

About Us
Reactive Markets is the 2026 OTC Trading Platform of the Year ( Risk.net ). Our network handles over $75 billion in daily trading volumes across FX, Equities, and Cryptocurrency, connecting 50+ of the world’s leading liquidity providers.
We build trading systems that operate at the edge of what’s technically possible — where nanoseconds matter and a dropped message costs real money. Our engineering team is small, senior, and deeply invested in the craft of building cutting edge, reliable, high-performance systems.

The Role
We’re looking for a Senior Infrastructure Engineer to help run and grow the network and cloud estate behind our trading platform. Networking in our colocation data centres is the core of the role. The estate spans London, New York and Singapore, and from Q1 2027 a new Tokyo data centre.
This is a hands-on role in a small, expert infrastructure team. You’ll work closely with our Head of Infrastructure, following problems from the cross-connect through hosts, containers and AWS. You’ll also help keep infrastructure delivery on track, from timelines and reporting to working closely with our TechOps team.

What You’ll Work On

• Low-latency networking across our colocation sites: switching and routing, cross-connects, BGP peering with liquidity providers and clients, and the fabric that carries our trading traffic

• Bringing new sites to application-ready, starting with Tokyo

• Our hybrid connectivity into multi-region AWS, including Direct Connect, routing and failover

• Linux hosts and containers on the critical path, with every change made through code (Ansible, Git, Terraform), never by hand

• Monitoring and alerting that catches problems before clients do, plus runbooks and post-incident reviews that someone else can follow

• Planning and capacity: forecasting growth, setting timelines and reporting progress to TechOps and engineering

What We Need

• 4+ years running production infrastructure in a latency-sensitive environment, such as HFT, an exchange, market data or bank trading infrastructure

• Strong networking: hands-on routing and switching (MLAG, LACP, VLANs), BGP in production, and a solid grasp of low-latency behaviour such as buffers, microbursts and congestion handling

• Colocation experience: cabinets, cross-connects, remote hands and vendor management

• Solid Linux (RHEL) and TCP/IP, and the ability to trace a problem from the wire to the application

• Infrastructure as code and containers as your default way of working

• Working knowledge of AWS networking, and the confidence to pick up the rest of our stack. Networking depth matters more to us than any particular cloud or platform tooling

• Methodical, evidence-led troubleshooting and clear documentation

A strong plus:

• Project management experience: owning timelines, reporting progress, and working with ops teams to hit deadlines

• Kernel bypass (Onload/ef_vi), PTP and time synchronisation

• Experience bringing up a new colo site

• FIX protocol or OTC FX market knowledge

• Python for tooling

Working pattern: Infrastructure changes are often scheduled outside trading hours, including weekends, and the team shares an on-call rota. We’re a team with flexible hours, so time worked out of hours is taken back during the week. Day-to-day work is remote, with occasional visits to our data centres, most often in London (Slough).

What You Get

• Real ownership of a live global trading network, hands-on, with few layers of process

• A build-out year, with a new Tokyo data centre in Q1 and more growth ahead

• A senior seat in a small, expert team where your changes ship and are measured

• Competitive package — up to 38 days leave (inc. bank holidays), private health insurance, pension, life insurance, dental/optical cashback, cycle to work, socials and offsites

• Remote-friendly working with flexibility around out-of-hours work

• Growth as the estate scales

We believe in transparency, honest feedback and writing things down, and we aim to build systems that don’t depend on the heroics of individuals.

Our Hiring Process
We keep our process focused and respectful of your time. Our process follows three stages:
Stage 1: Initial Conversation with Talent Acquisition
Format: Video call, ~30-45 minutes
Stage 2: Technical Deep Dive with our Head of Infrastructure
Format: Video call, interactive session, ~90 minutes
Stage 3: Leadership Conversation with our CDO
Format: Video call, ~45 minutes
What to expect in each stage will be explained by Talent Acquisition if you’re invited to interview. Throughout the process, we aim to keep momentum with no unnecessary delays between stages, and feedback typically comes within a few business days.

How to Apply
Please apply directly via this job posting — all applications, including those submitted via LinkedIn, are managed through our applicant tracking system, so you’ll always land in the same place regardless of where you found this role.
Right to Work: Candidates must have the existing right to work in the UK. We are not currently able to offer visa sponsorship for this role.
Equal Opportunities: Reactive Markets is an equal opportunities employer. We welcome applications from all qualified candidates regardless of age, disability, gender reassignment, marriage or civil partnership, pregnancy or maternity, race, religion or belief, sex, or sexual orientation.
Reasonable Adjustments: If you need any adjustments or support during the application or interview process, please let us know — we’re happy to accommodate.
Data Protection: By applying, you consent to Reactive Markets processing your personal data for recruitment purposes, in line with our privacy policy.…

Source: Arbeitnow (https://www.arbeitnow.co.uk/jobs/companies/reactive-markets/senior-infrastructure-engineer-united-kingdom-438636)