Hybrid FIX Onboarding & Client Services Specialist

Academic Key; Greater London; Hybrid; GBP 65,000 - 95,000; Full time

Job summary

Reactive Markets in London is seeking a motivated Onboarding and Client Services professional to join our hybrid London team. This role focuses on FIX onboarding, integrations, and client service delivery across FX, equities and digital assets, utilizing AI-enabled tooling to streamline processes.

The successful candidate will coordinate onboarding from requirements through production go-live, work with engineering on new FIX workflows, and provide frontline technical support across EMEA.

Qualifications

• 2-5 years of experience in a client onboarding, integration, or technical support role within financial technology, trading, or brokerage.
• Good working knowledge of the FIX protocol — message structures, session management, and common trading workflows.
• Genuine comfort troubleshooting FIX connectivity, analysing logs, and resolving integration issues.
• Familiarity with FX and Equities trading environments, order lifecycle management, and market data connectivity.
• A genuinely proactive, tech-first mindset — AI and automation tooling to improve processes.
• Excellent communication and organisational skills, with the ability to manage multiple onboarding/client projects in parallel.
• Nice-to-have: Experience with OMS/EMS platforms, liquidity aggregators, or trading system integrations.
• Exposure to other API protocols (REST, WebSocket) and scripting (Python).

Responsibilities

• Lead and manage FIX client onboarding projects — from initial requirements gathering through certification and production go-live.
• Configure, test, and validate FIX sessions, including order routing, execution reporting, and market data flows.
• Coordinate conformance testing and certification with clients to ensure compliance with platform standards.
• Document onboarding procedures, client configurations, and integration best practices.
• Leverage internal AI and automation tools to streamline client onboarding and troubleshooting.
• Collaborate with engineering and product teams to support new FIX workflows, APIs, and client integration initiatives.
• Serve as frontline technical support for clients in EMEA across FX and equities business lines.
• Build and maintain strong client relationships with timely and professional communication.
• Provide ongoing technical and operational support for production trading environments.
• Manage client inquiries, troubleshoot workflow or configuration issues, and coordinate resolutions across internal teams.
• Partner with account management, sales and product teams to ensure positive client experience and successful delivery of platform enhancements.

Skills

FIX protocol

Troubleshooting FIX

Python scripting

REST/WebSocket API

FX/Equities trading

Client onboarding

Communication

Tools

OMS/EMS platforms

Job description

Reactive Markets in London is seeking a motivated Onboarding and Client Services professional to join our hybrid London team. This role focuses on FIX onboarding, integrations, and client service delivery across FX, equities and digital assets, utilizing AI-enabled tooling to streamline processes.

The successful candidate will coordinate onboarding from requirements through production go-live, work with engineering on new FIX workflows, and provide frontline technical support across EMEA.