Core Engineer - DeFi

🔒 Confidential Employer
Posted 23 April 2026
LOCATION
London
TYPE
Full-time
LEVEL
Mid-Senior level
CATEGORY
Technology
This employer holds a UK Home Office sponsor license — sponsorship for this specific role is at the employer’s discretion

SKILLS

DeFi Integrations Go C++ API design Postgres Typescript

FULL DESCRIPTION

[Employer hidden — view at passion-project.co.uk] is seeking a Core Engineer to join their team in London. The role involves building a back-office system for digital assets, integrating with DeFi protocols, and automating reconciliation processes. The ideal candidate will have experience with crypto asset classes, DeFi protocols, and strong technical skills in Go, C++, or similar languages.

Mission

Be a key player in the newly formed Core Engineering team at [Employer hidden] to build a world class back office system which will serve as the backbone for [Employer hidden]'s systems. Work alongside a seasoned team with deep product, buy‑side, and sell‑side experience in both Crypto and TradFi.

Tasks

  • DeFi Integrations - Collect all necessary on-chain data and integrate with decentralized protocols to power an accurate, real-time back office system. You will be responsible for ensuring management has a comprehensive, up-to-date view of all on-chain assets. This includes owning the full process from requirements analysis, task specification, implementation, to post-production support.
  • Core Booking / Aggregation - Implement and enhance features in the core booking and aggregation engine (Realised / Unrealised P&L, Balances etc) ensuring performance, reliability and correctness.
  • Reconciliation - Automate reconciliation of all trading and treasury activity across the firm implementing data feeds from internal systems, banking, exchanges and custodians.
  • Reporting - Work closely with the Finance and other internal users to gather and refine requirements, plan milestones, demo progress, and coordinate cutovers from manual / legacy workflows.
  • Data products and APIs - Expose well-versioned APIs and event streams for downstream consumers; maintain backward compatibility and schema evolution.

Ways of working

  • Follow established architecture and coding standards; participate in RFCs/design reviews and propose incremental improvements within existing patterns.
  • Write clean, well-documented code and meaningful tests.
  • Contribute to PR reviews; maintain up-to-date technical docs and diagrams.
  • Own components end-to-end from spec to production support.

Requirements****Must Haves - Experience

  • Lifecycle knowledge of crypto asset classes{{{{:}}}} spot, perpetuals, futures, and options (including DeFi implementations).
  • Hands-on integration with Defi protocols (DEX/AMM, lending, derivatives) such as Uniswap v3, Curve, Aave.
  • Proven track record delivering scalable, reliable systems in production.
  • Comfortable partnering with internal stakeholders across Trading, Ops, Compliance, and Engineering.

Must Haves - Technical

  • Strong OO background in one or more, Go, C++, C#, Java or Rust.
  • Experience with Typescript and Python.
  • API design (versioning, backwards compatibility, observability)
  • Postgres schema design and query optimization.
  • Experience with message queue / pub-sub systems.
  • Familiarity with cloud environments (GCP, AWS, Azure), modern CI/CD and containerization.

Nice-to-Haves - Experience

  • Built or maintained position-keeping / accounting systems (PnL, accounting methods, pricing, greeks).
  • Centralized reference data platforms (assets, networks, instruments), consistent symbology and instrument economics.
  • Trading, risk, or back-office systems, ideally in regulated environments.

Benefits

  • International environment (English is the main language)
  • Pension
  • 100% health coverage
  • Team events and offsites
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