Senior Backend Engineer/Head of Backend Development (Python / AWS)

Fintech | NYC (Remote) | No C2C | Full-time role

Compensation: £100,000–£160,000 (negotiable for star talent upon tech test)

We are working with a well-funded fintech platform transforming how complex financial data flows across global markets. This is an early engineering hire with direct report line to the CTO in London, providing the opportunity to shape the architecture and set engineering standards from the start.

The Impact

● Build mission-critical infrastructure that enables global investment banks to transition from manual legacy processes to a high-throughput, automated data ecosystem.

● Power revenue transformation by turning internal back-office valuation data into institutional-grade distribution products.

● Shape the architecture, cloud strategy, and engineering culture of a venture-backed fintech at an early stage.

The Role

This is a senior backend role focused on designing and scaling the core engine that powers ingestion, validation, and distribution workflows. The environment demands production-grade reliability, security, and performance aligned to the expectations of tier-one financial institutions.

You will primarily work in Python and AWS, building robust APIs and scalable data pipelines. This is not simply CRUD API development; it involves architecting high-trust systems with strong multi-tenant boundaries, regional data controls, and secure cloud infrastructure.

The process includes an intensive technical assessment, reflecting the complexity and rigor of the platform.

What You’ll Do

● Architect and implement production-grade REST APIs using Python (FastAPI) to manage complex financial data submissions.

● Design secure ingestion pipelines for large-scale datasets (CSV/Parquet), leveraging S3, presigned URLs, automated webhooks, and high-performance data libraries such as Polars or Pandas.

● Develop sophisticated backend logic for consensus workflows, regional data isolation (LDN/NY/HK), and strict multi-tenant security boundaries.

● Build and optimize cloud-native infrastructure across AWS services including ECS/Fargate, RDS/PostgreSQL, Lambda, CloudFront, IAM, and KMS-managed encryption.

● Establish engineering excellence through clean architecture, unit testing, CI/CD standards, observability practices, and performance monitoring.

● Participate in architecture discussions and contribute directly to the technical roadmap as a foundational engineering voice.

What They’re Looking For

Must-Haves

● Significant production experience building and maintaining complex backend systems in Python.

● Strong working knowledge of AWS and deploying cloud-native applications.

● Experience with containerization (Docker) and modern deployment workflows.

● Systems-level thinking with an emphasis on clean abstractions, testing, and architectural trade-offs.

● Ownership mindset with comfort operating in ambiguity and taking features from concept through to production.

Nice-to-Haves

● Experience with FastAPI, Pydantic, or SQLAlchemy.

● Infrastructure as Code exposure (Terraform preferred).

● Experience working with data-heavy workflows, market data, or formats such as Parquet.

● Background in fintech or regulated environments with awareness of SOC2, encryption standards, and secure data handling.

This team will prioritise candidates who demonstrate stable tenure and consistent impact in previous roles. They are building for the long term and value engineers who commit, own, and scale with the business.

If you’re a senior backend engineer who wants architectural influence, real ownership, and the opportunity to build secure financial infrastructure from the ground up, this is a rare early-stage opportunity with meaningful technical depth.