Application Support & Client Onboarding Engineer: Trading Technology

Marlin Selection; Greater London; On-site; GBP 60,000 - 90,000; Full time

Benefits offered by this job

Office lunches provided

Job summary

Marlin Selection represents a leading financial technology provider hiring an Application Support Engineer to join the customer-facing onboarding team in London. You will be first point of contact for operational and technical issues, assisting onboarding from setup to go-live and ongoing support.

You’ll tailor your communication to institutional and retail clients, triage issues across network, OS and application layers, and build deep expertise in digital assets within a fast-moving trading

Qualifications

• Experience 2–5 years supporting clients in financial services.
• Experience onboarding institutional and retail clients.
• Knowledge of FIX protocol.
• Basic TCP/IP networking knowledge.
• Basic SQL (PostgreSQL, MySQL).
• Proficient Windows power-user.
• Excellent written and verbal communication.
• Ability to manage multiple client conversations under pressure.

Responsibilities

• Deliver customer support via email, phone and live chat in line with SLAs for institutional and retail clients.
• Support and onboard new institutional and retail clients through implementation, configuration, testing and go-live.
• Act as technical first responder, triaging issues across network, OS and application layers, prioritising and escalating by severity.
• Analyse logs, FIX messages and other primary sources to identify root causes of trading and quoting issues.
• Configure client setups, including liquidity provider details, order routing, trading platform connectivity and prime broker give-up arrangements.
• Manage upgrades and migrations of the platform and related software, performing full system check-outs on completion.
• Tailor communication and documentation to the client’s technical level, from experienced institutions to retail users.
• Build subject matter expertise and act as the team’s go-to person.

Skills

Client support

Onboarding experience

FIX protocol

Networking basics

SQL databases

Windows proficiency

Strong communication

Multi-client handling

Job description

My client is a leading financial technology provider supplying trading and liquidity infrastructure to a broad client base, from large institutions to retail-focused brokers and their end clients. They are hiring an Application Support Engineer to join their customer-facing support and onboarding team.

You will be the first point of contact for clients on operational and technical issues, and will play a hands‑on role in onboarding new clients, from initial setup through to go‑live and ongoing support. You will adapt your approach to each client type: in-depth technical engagement with institutional desks, and clear, accessible guidance for retail-facing clients. It suits someone who enjoys problem-solving in a fast-moving trading environment and wants to build deep expertise in digital assets.

Key responsibilities

• Deliver customer support in line with agreed SLAs via email, phone and live chat, across both institutional and retail client segments
• Support and onboard new institutional and retail clients, guiding them through implementation, configuration, testing and go‑live
• Act as technical first responder, triaging issues across network, OS and application layers, and prioritising and escalating by severity
• Analyse logs, FIX messages and other primary sources to identify the root cause of trading and quoting issues
• Work with clients to configure their setup, including liquidity provider details, order routing, trading platform connectivity and prime broker give‑up arrangements
• Manage upgrades and migrations of the platform and related software, carrying out full system check‑outs on completion
• Tailor communication and documentation to the client’s technical level, from experienced institutional connectivity teams to retail-focused users
• Build subject matter expertise and act as the team’s go‑to person

Skills and experience

• 2-5 years’ experience supporting clients in financial services
• Experience supporting or onboarding clients, ideally across both institutional and retail segments
• Working understanding of the FIX protocol
• Basic knowledge of TCP/IP and networking
• Basic SQL (PostgreSQL, MySQL)
• Power‑user level proficiency with Microsoft Windows
• Excellent verbal and written communication, with strong attention to detail
• Able to manage several client conversations at once and make sound decisions under pressure

Personal attributes

• Confident adjusting tone and technical depth to suit very different audiences
• Keen to learn new tools and skills
• Resilient, and enthusiastic about taking on tough challenges

Why this role?

• Hands‑on exposure to institutional trading infrastructure
• A varied client base, giving you experience across both institutional and retail markets
• Ownership of the client journey from onboarding through to live support, with clear routes to specialise
• Office Lunches provided

Application Support & Client Onboarding Engineer: Trading Technology London, United Kingdom