At a Glance
- Tasks: Lead the architecture and delivery of innovative AI-driven payment systems.
- Company: Global payments tech company focused on empowering teams and solving real-world problems.
- Benefits: Competitive salary, remote work, and opportunities for professional growth.
- Other info: Join a culture that values autonomy, craft, and impactful outcomes.
- Why this job: Tackle exciting challenges at the intersection of AI and payments technology.
- Qualifications: 8-10 years in software engineering with expertise in TypeScript/Node.js or Python.
The predicted salary is between 80000 - 100000 £ per year.
At a Glance
- Role: Principal Engineer, AI Platform (MCP)
- Location: Remote
- Salary: Competitive
- Employment type: Permanent, full-time
- Stack: TypeScript / Node.js or Python, MCP SDKs, OAuth 2.0 / OIDC, Cloudflare Workers, Streamable HTTP
The Company
Our client is a global payments technology business building the next generation of capabilities for a merchant-first ecosystem. They operate at real scale, working with partners and merchants across multiple markets, and their engineering culture is built around small, empowered teams solving hard, real-world problems. The culture here is outcomes over outputs. Teams are trusted to work with autonomy, supported with the right tools, and given the space to think carefully and build well. If you are the kind of engineer who wants to master a domain rather than just ship tickets, this is the right environment.
The Role
This is one of the most technically interesting principal engineering roles we have brought to market this year. You will own the architecture and delivery of a suite of Model Context Protocol (MCP) servers that serve as the trusted, governed gateway between large language models and a production payment platform. As AI-driven interfaces become a primary way partners and internal teams interact with payment systems, these servers sit at the heart of that shift. You will define the transport and session model, implement OAuth-based authentication and authorisation, design the tooling and elicitation surfaces that agents depend on, and build the operational backbone that keeps everything safe and reliable at scale. This is a hands-on principal role. You will set technical direction, write production code, define patterns and libraries that other teams will build on, and raise the bar for engineering quality across a domain that is new, fast-moving, and security-sensitive.
What You'll Be Doing
- Own the architecture and delivery of MCP servers exposing platform data and capabilities to AI agents and developer tooling
- Design the transport and session model (Streamable HTTP), including stateful sessions for progress streaming, subscriptions, sampling, and user elicitation flows
- Implement robust authentication and authorisation using OAuth 2.0 / OIDC, JWT validation, and least-privilege per-request data scoping
- Design and operate the edge and gateway layer (Cloudflare Workers / Durable Objects) for token validation, JWKS caching, routing, and session state
- Define standards, patterns, and reusable libraries so other teams can build additional MCP servers quickly, consistently, and securely
- Embed security and compliance into every layer, treating these servers as a high-trust surface over sensitive payment data
- Drive observability, performance, and reliability: logging, tracing, rate limiting, timeouts, graceful degradation, and clean failure modes
- Build quality in across the software lifecycle using Behavioural Driven Development and CI/CD
- Mentor engineers, review designs and code, and evaluate emerging AI and agent technologies for applicability
- Translate partner, merchant, and internal developer needs into well-designed, high-quality solutions
What You'll Bring
Essential- 8 to 10 years of software engineering experience, with a track record of owning systems end to end
- Deep server-side development expertise in TypeScript / Node.js or Python, given the maturity of the official MCP SDKs
- Strong, hands-on familiarity with the Model Context Protocol: defining tools, resources, and prompts; designing well-typed input/output schemas; and writing tool descriptions that drive reliable model behaviour
- Solid understanding of LLM tool-use and agentic patterns, including how models select and invoke tools, manage context, and handle multi-step interactions
- Hands-on experience with OAuth 2.0 / OIDC, JWT validation, token scoping, and identity provider integration
- Experience deploying and operating services at the edge or in serverless environments (Cloudflare Workers / Durable Objects, AWS Lambda, Cloud Run, or comparable)
- Strong understanding of secure HTTP API design, including streaming and SSE, and stateful vs. stateless service design
- Security-first mindset, ideally with exposure to regulated or payments environments (PCI DSS awareness a strong plus)
- Awareness of the safety considerations specific to AI agent tooling: prompt injection, over-broad permissions, and safe handling of model-driven actions
- Solid grounding in database design, caching, message-oriented middleware, and systems integration
- Comfortable operating with a high degree of ambiguity, able to set direction, experiment, and backtrack when needed
- Direct experience building with agent frameworks or LLM application SDKs beyond MCP
- Background in payments or other regulated financial services environments
- BS or MS in Computer Science or a related field
Why Apply
- A genuinely novel technical problem at the intersection of payments infrastructure and AI agent systems
- Principal-level ownership with real architectural authority and scope to define how this domain is built
- A culture that values engineering craft, autonomous teams, and outcomes over process
- No needless bureaucracy: small teams, hard problems, space to do your best work
- Competitive compensation with the ability to grow with a business operating at serious scale
Interested? Apply directly or reach out to Ryan Quinn at Ocho for a confidential conversation.
Principal Engineer employer: Ocho Ocho
Our client is an exceptional employer, offering a dynamic remote work environment that fosters innovation and autonomy. With a strong emphasis on engineering excellence and a culture that prioritises outcomes over outputs, employees are empowered to tackle complex challenges while enjoying competitive compensation and ample opportunities for professional growth. This role not only allows you to influence the architecture of cutting-edge payment technologies but also positions you at the forefront of AI integration in financial services, making it a truly rewarding career choice.
StudySmarter Expert Advice🤫
We think this is how you could land Principal Engineer
✨Tip Number 1
Network like a pro! Reach out to folks in your industry on LinkedIn or at meetups. A personal connection can often get you a foot in the door faster than any application.
✨Tip Number 2
Show off your skills! Create a portfolio or GitHub repository showcasing your projects, especially those relevant to AI and payments tech. This gives potential employers a taste of what you can do.
✨Tip Number 3
Prepare for interviews by practising common technical questions and scenarios related to the role. We recommend doing mock interviews with friends or using online platforms to boost your confidence.
✨Tip Number 4
Don’t forget to apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, it shows you’re genuinely interested in joining our team.
We think you need these skills to ace Principal Engineer
Some tips for your application 🫡
Tailor Your Application:Make sure to customise your CV and cover letter for the Principal Engineer role. Highlight your experience with TypeScript, Node.js, or Python, and showcase any relevant projects that demonstrate your expertise in server-side development and AI technologies.
Showcase Your Problem-Solving Skills:We want to see how you tackle complex challenges! Include examples of how you've owned systems end-to-end and solved real-world problems, especially in payments technology or AI. This will help us understand your approach to engineering.
Be Clear and Concise:When writing your application, keep it straightforward. Use clear language and avoid jargon where possible. We appreciate a well-structured application that gets straight to the point while still showcasing your skills and experiences.
Apply Through Our Website:Don't forget to apply directly through our website! It’s the best way for us to receive your application and ensures you’re considered for this exciting opportunity. We can’t wait to hear from you!
How to prepare for a job interview at Ocho Ocho
✨Know Your Tech Stack Inside Out
Make sure you’re well-versed in TypeScript, Node.js, or Python, as these are crucial for the role. Brush up on your knowledge of OAuth 2.0 / OIDC and Cloudflare Workers, as you might be asked to discuss how you would implement these technologies in real-world scenarios.
✨Demonstrate Your Problem-Solving Skills
Prepare to showcase your ability to tackle complex engineering challenges. Think of examples from your past experience where you’ve designed systems or solved problems that align with the responsibilities of owning architecture and delivery of MCP servers.
✨Showcase Your Security Mindset
Given the security-sensitive nature of the role, be ready to discuss your approach to secure HTTP API design and how you’ve embedded security into your previous projects. Highlight any experience you have with PCI DSS or similar regulations.
✨Be Ready to Discuss AI and Agent Technologies
Since this role involves working with AI-driven interfaces, brush up on your understanding of LLM tool-use and agentic patterns. Be prepared to talk about how you would translate partner and merchant needs into high-quality solutions using these technologies.
