Blockchain Payments Engineer

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, FedNow, 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, TrueLayer), processing (Stripe, Adyen), and on-chain compliance (Chainalysis, TRM).

Real-Time Risk & Compliance

• Build and scale a real-time risk engine targeting latencies of $\le 300$ms, 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 OpenTelemetry 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 TypeScript/Node/Python.
• Database Mastery: Expert-level knowledge of Postgres (transactions, indexing, locking), with familiarity in Redis and event/OLAP stores (Kafka/Redpanda, ClickHouse).
• 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 for regulatory/tax reporting.
• Crypto Delivery: Solana RPCs, USDC flows, wallet operations, and Chainalysis/TRM integrations.
• Infra: Experience with AWS, Terraform, Docker/Kubernetes, and OpenTelemetry/Prometheus/Grafana.

• High-Impact Ownership: Every team member is empowered to make significant architectural and business decisions.
• Talent Density: Work alongside an elite group of engineers and builders in a high-performance environment.
• Cutting-Edge Tech: Direct exposure to a modern stack including Rust, Go, Kafka, and AWS (EKS, RDS, KMS).
• Speed & Autonomy: An environment that values shipping and iteration over bureaucracy and perfectionism.
• Competitive Package: A high-tier compensation structure including Base Salary plus Equity/Tokens.

Due to the high volume of applications we anticipate, we regret that we are unable to provide individual feedback to all candidates. If you do not hear back from us within 4 weeks of your application, please assume that you have not been successful on this occasion. We genuinely appreciate your interest and wish you the best in your job search.

Commitment to Equality and Accessibility:

At MLabs, we are committed to offer equal opportunities to all candidates. We ensure no discrimination, accessible job adverts, and providing information in accessible formats. Our goal is to foster a diverse, inclusive workplace with equal opportunities for all. If you need any reasonable adjustments during any part of the hiring process or you would like to see the job-advert in an accessible format please let us know at the earliest opportunity by emailing [email protected].

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