Blockchain Engineer

Lead Blockchain Payments Engineer - Fiat Ramps & Financial Infrastructure

Location: London

On-site| Full-time

Compensation: Competitive

Our client is an elite team of builders operating at the intersection of fintech and high-scale crypto infrastructure. As a high-growth software organization, the company is responsible for developing the technology behind some of the largest crypto social networks and digital asset launchpads globally. The organization is defined by a philosophy of extreme talent density, rapid iteration, and technical ownership.

The Lead Blockchain Payments Engineer (Fiat Ramps) will serve as a core architect of the firm's financial infrastructure. This role is responsible for designing and scaling the services that power seamless fiat-to-crypto flows, real-time risk decisioning, and immutable financial records. Based in London
, this is a full-time,
in-person position for an engineer who thrives in high-throughput, low-latency environments and is passionate about building the future of global value transfer.

Key Responsibilities

Payment Orchestration & Integrations

• Own end-to-end orchestration for major bank rails (ACH, RTP, Fed Now, SEPA, Open Banking) and card networks (Apple Pay, Google Pay).
• Design and implement idempotent, fault-tolerant APIs and robust webhook processing systems.
• Manage third-party provider integrations for connectivity (Plaid, True Layer), processing (Stripe, Adyen), and on-chain compliance (Chainalysis, TRM).

Real-Time Risk & Compliance

• Build and scale a real-time risk engine targeting latencies of &le 300ms, incorporating ML scores, device signals, and blockchain analytics.
• Implement foundational KYC/AML primitives and Travel Rule data plumbing in collaboration with the Compliance team to ensure audit-ready journaling.

Financial Integrity & Reconciliation

• Architect a double-entry ledger and automated reconciliation jobs to synchronize processors, bank statements, and on-chain balances.
• Develop automated break detection and remediation workflows to maintain absolute financial integrity.

Blockchain & Wallet Operations

• Manage hot-wallet flows, transaction creation, and operational safeguards to ensure safe, rapid delivery of crypto assets (e.g., USDC, SOL).

Reliability & Instrumentation

• Establish high standards for reliability using circuit breakers, dead-letter queues, shadow traffic, and canary releases.
• Instrument all high-risk financial flows with comprehensive traces, metrics, and logs using Open Telemetry and Grafana.

Cross-Functional Collaboration

• Work closely with Product, Mobile, Compliance, Risk, and Finance teams to drive features from initial concept through production deployment and iteration.

• Fiat Onramp Expertise: Proven experience building fiat ramps end-to-end
  , including bank and card integrations.
• System Design & Scale: Deep experience designing and scaling high-throughput, low-latency distributed systems in payments, fintech, or risk platforms.
• Language Fluency: Fluent in one or more systems languages (Rust, Go), or strong systems chops in Type Script/Node/Python
  .
• Database Mastery: Expert-level knowledge of Postgres (transactions, indexing, locking), with familiarity in Redis and event/OLAP stores (Kafka/Redpanda, Click House).
• API & Webhook Craftsmanship: Mastery of gRPC/REST best practices (versioning, idempotency keys) and building rock-solid webhook consumers.
• Event-Driven Design: Experience designing systems with queues, outbox/inbox patterns, Sagas, and ensuring exactly-once-effective behavior for financial transactions.
• Security Mindset: Practical experience with key management (HSM/KMS), secrets hygiene, least privilege, and data auditability.
• Ownership & Ambiguity: Ownership-driven and comfortable operating in high-ambiguity environments—you move quickly, measure results, and iterate aggressively.

• Payments: ACH/NACHA returns, 3DS/SCA, AVS/CVV, BIN analysis, chargeback workflows, Apple/Google Pay.
• Compliance Plumbing: Experience with sanctions/PEP screening, Travel Rule networks (e.g., Notabene/TRISA), and SAR/STR workflow integration.
• Accounting: Experience with double-entry ledgers, reconciliation jobs, and data modeling…