Senior Software Engineer / Staff Engineer / Architect

Mission.dev; United Kingdom; Remote; GBP 121,590 - 151,988; Full time

Job summary

A leading digital financial solutions company seeks a Senior Software Engineer / Staff Engineer / Architect to develop its AI-driven banking platform. The role involves designing secure serverless backends and developing user-friendly interfaces with React Native. Candidates should have over 10 years of experience in software engineering, with a focus on fintech applications. This is a full-time remote position.

Qualifications

• 10+ years of software engineering experience.
• 5+ years in mobile-first or fintech applications.
• Proven experience in delivering secure financial software.

Responsibilities

• Develop mobile and web interfaces using React Native.
• Design scalable APIs and data pipelines on AWS.
• Provide technical guidance and mentorship to peers.

Skills

React Native + Expo

TypeScript development

Serverless architectures

AI-assisted development

Real-time networking technologies

Tools

AWS (Lambda, DynamoDB, Kinesis)

Sentry

Better Stack

Job description

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Base pay range

$160,000.00/yr - $200,000.00/yr

Agreement type: This is a full-time employment role, requiring 40 hours per week, directly hired by the client.

Location of the engineer: Remote 100%.

About the client

The client is a company developing the next generation of digital financial products. Their mission is to build scalable, secure, and highly customizable banking solutions that merge traditional fintech capabilities with cutting-edge AI innovations. Their multidisciplinary teams—spanning engineering, design, and machine intelligence—deliver platforms that make financial operations smarter, faster, and more transparent. They value craftsmanship, autonomy, and curiosity, qualities that enable them to move quickly while maintaining precision. With a global presence and a remote-first culture, the client brings together specialists from finance, blockchain, and artificial intelligence to push the boundaries of what’s possible in digital money and data systems.

About the role

We are looking for a senior Fullstack Software Engineer to help build the foundation of our AI-driven digital banking platform. This role combines deep technical ownership with product craftsmanship. You will design and implement features that connect modern frontend interfaces with secure, scalable serverless backends, enabling real-time, data-intelligent financial interactions. You’ll work across the full product stack, collaborating with design, data, and AI teams to deliver polished user experiences backed by robust cloud infrastructure. This is an opportunity to join a small, high-impact engineering team where your work directly shapes how people interact with intelligent financial tools.

What You’ll Do

• Develop and ship production-grade mobile and web interfaces using React Native with Expo, ensuring design precision and smooth performance.
• Take ownership of core fintech product modules such as digital wallets, payments, transaction ledgers, onboarding, and notification systems.
• Design and maintain scalable APIs and data pipelines within a serverless AWS environment (Lambda, API Gateway, DynamoDB, Kinesis, EventBridge).
• Integrate digital asset and stable-value payment flows while maintaining high standards for compliance and data protection.
• Build real-time, event-driven user experiences using WebSockets and server-streaming connections, including conversational and AI-assisted features.
• Enhance app performance and reliability using profiling and monitoring tools like Sentry and Better Stack, along with libraries such as Hermes, Reanimated, and FlashList.
• Partner with design teams to translate Figma prototypes and design tokens into consistent UI implementations.
• Apply AI-supported development workflows (e.g., using Cursor, Claude, or related assistants) to accelerate delivery and improve testing coverage.
• Contribute to team-wide standards for AI-assisted development, evaluating new tools that enhance velocity and quality.
• Provide technical guidance and mentorship to peers, promoting best practices for building secure, performant, AI-integrated fintech systems.

What You Bring

• 10+ years of professional software engineering experience, including 5+ years in mobile-first or fintech applications.
• Proven experience delivering complex, secure, and high-quality financial software in production environments.
• Deep expertise with React Native + Expo and modern TypeScript development across frontend and backend layers.
• Strong background in serverless architectures and AWS cloud services.
• Understanding of secure identity management (JWT, Cognito, or comparable systems) and financial-grade data security practices.
• Familiarity with stablecoin payment mechanisms, blockchain integrations, or payment APIs.
• Practical knowledge of real-time networking technologies (WebSockets, SSE).
• Experience using AI-enhanced IDEs or developer tools in daily workflows.
• A mindset geared toward innovation and experimentation, especially around how AI changes the software development process.

Preferred Experience

• Understanding of blockchain-based transactions or tokenized payments.
• Familiarity with design systems, performance optimization, and testing automation.
• Experience mentoring engineers or leading small, cross-functional development teams.

Senior Software Engineer / Staff Engineer / Architect - Summary