Customer Onboarding; FIX Specialist

Customer Onboarding (FIX) Change Consultant 6-Month Contract | Up to £500/day | Inside IR35 Hybrid London (2–3 days per week) Overview

Our client, a leading electronic trading business is delivering a number of complex change programmes impacting customer connectivity, onboarding and infrastructure. These initiatives involve transitioning institutional connectivity from legacy to new within a live, regulated trading ecosystem.

This role sits within the Customer Onboarding (FIX), supporting a highly experienced and knowledgeable team that is managing an increased workload as a result of the change programme of work. Additional delivery capacity is required to ensure customer migrations and onboarding activity continue to be executed in a controlled and structured manner.

This is a hands‑on, delivery‑focused position supporting structured customer migrations, certification activity and onboarding change, ensuring controlled transitions with minimal disruption.

The role combines technical FIX knowledge with strong stakeholder management, structured problem‑solving and significant documentation ownership.

• Lead Customer Onboarding (FIX) session setup for migrating and new connections
• Manage end‑to‑end connectivity testing, certification and validation
• Execute structured migration and onboarding workpacks
• Coordinate controlled customer cutovers and transition planning
• Identify and resolve onboarding or connectivity issues proactively
• Draft, update and maintain onboarding documentation, process guides and operating procedures
• Enhance migration templates and strengthen repeatable onboarding standards
• Manage multiple concurrent onboarding initiatives
• Engage and align stakeholders across US, EU and APAC time zones
• Provide structured updates into programme governance forums

• Strong understanding of FIX Protocol (sessions, connectivity, message structures)
• Experience delivering Customer Onboarding (FIX) or connectivity change within trading environments
• Exposure to infrastructure or data centre migration programmes
• Excellent stakeholder management skills across both technical and commercial audiences
• Demonstrable problem‑solving ability within live, time‑sensitive environments
• Strong documentation and process‑writing capability
• The ability to work independently in a hands‑on, delivery‑focused role
• Comfort operating within regulated trading environments