Principal C# Developer .Net AWS - FinTech

Hidden Jobs; United States; Hybrid; USD 127,000 - 175,000; Full time

Benefits offered by this job

Pension 5% employer contribution

Holidays 25→27→30 days

Life assurance

Employee assistance program

Job summary

Hidden Jobs, a growing fintech, seeks a senior software engineer to drive backend systems on the .NET stack, with exposure to Python and cloud services. You will shape architecture, mentor peers, and collaborate with cross-functional teams in a two-week sprint cycle.

The role emphasizes AI-enabled capabilities from chatbots to developer tooling and reports to the CTO. The position involves designing scalable services, championing quality, and delivering on strategic priorities across the

Qualifications

• Production software engineer with solid backend experience.
• Strong C# and .NET knowledge; Python exposure beneficial.
• Experience with a major public cloud (AWS) and distributed systems.
• Strong CS fundamentals and design patterns.
• Interest in AI and developer tooling.

Responsibilities

• Design and build scalable, high-throughput backend services.
• Architect components on a Microsoft stack; services hosted on a leading public cloud.
• Collaborate with product, design, and other squads in Agile sprints.
• Champion code quality, delivery discipline, and timely releases.
• Identify and prototype AI use cases, chatbots, and developer tooling.
• Mentor peers and advise on technical direction.

Skills

C# backend

.NET stack

Python exposure

Cloud (AWS)

OO design

Tools

AWS

Job description

Role overview

A senior hands-on engineering position sits at the core of a growing financial technology organisation that is building highly performant, scalable services on a modern Microsoft technology stack. The role partners with cross-functional Agile squads working in two-week sprints and reports directly to the Chief Technology Officer, giving the hire significant architectural influence and visible impact. A major theme of the position is exploring and embedding artificial intelligence capabilities — from chatbots to developer-assist tooling — across the business.

Responsibilities

• Design and build scalable, high-throughput backend services applying SOLID principles and modern engineering best practice.
• Architect components across a Microsoft technology stack with services hosted on a leading public cloud platform.
• Collaborate closely with product, design, and other engineering squads inside an Agile delivery model running two-week sprints.
• Act as a champion of code quality, delivery discipline, and on-schedule release execution.
• Identify and prototype artificial intelligence use cases, including chatbots and tooling that assist developers.
• Mentor peers and partner with senior leadership on technical direction.

Requirements

• Substantial professional experience as a software engineer working on production systems.
• Strong C# backend skills on the .NET stack, with bonus exposure to Python.
• Practical knowledge of a major public cloud platform (AWS-class services) and building distributed, scalable systems.
• Solid grasp of computer science fundamentals, including object-oriented design, data structures, and design patterns.
• Demonstrated — or a clear active interest in — applied artificial intelligence and modern AI developer tooling.
• Strong analytical, problem-solving, planning, and stakeholder-communication skills.

Benefits and work setup

• Base salary up to roughly £120,000, with a bonus around 20%.
• Pension with a 5% employer contribution.
• 25 days of holiday, rising to 27 after two years and 30 thereafter.
• Life assurance covering four times base salary and an employee assistance programme.
• Hybrid arrangement based in London, with two days a week in modern offices and two days remote (Thursdays and Fridays).
• Structured training, supported learning, and clear career-development pathways.