Staff Engineer - Fintech
You will own the agents, skills and standards that let a tribe of product builders move quickly on payments without the architecture fragmenting. Hotels take payments across regions and through providers that each behave differently, and Payment Interfaces exists to give customers one coherent payment experience on top of several PSPs. Embedded payments at this depth is rare among European SaaS companies, so the problems here are ones few engineers get to work on.
You will be a Staff Engineer in the Payment Interfaces team, part of the Fintech tribe. You will report to the Director of Product and Engineering, sit in the tribe’s leadership group, and work alongside product builders, other staff engineers and product managers. No one reports to you, so your influence comes from the architecture, tools and standards that other people choose to work in.
The team integrates several PSPs depending on region and conditions. When integrations drift apart, builders slow down and quality suffers. This role exists to keep them coherent by encoding what good looks like into tools and agents, so every builder meets the standard by default.
What you would do
Own the tribe’s engineering agents, skills and context, and encode architectural standards, review logic and quality gates into them so the standard is met by default.
Build an AI first responder for customer tickets about payment issues, with clear rules for when it answers and when it hands over to a person.
Stay hands-on for the hardest technical problems: migrations, system-wide refactors and long-lived architecture decisions across PSP integrations.
Keep Payment Interfaces integrations coherent as PSPs and regional requirements change, collaborating with builders who own their own work.
Coach builders and fix off-standard outcomes at the cause, so the lesson sticks.
AI Fluency Level 4: in this role, that means you build the AI systems the tribe works in, not only use them. You design the agents, skills and evaluations that builders rely on every day, make the engineering decisions about how they behave, and set the rules for when an AI answer can stand and when a person must step in.
For more information on AI fluency at Mews, please refer to “AI Fluency at Mews: A Comprehensive Guide for Candidates” on Confluence.
What you would bring
Hands-on experience integrating with payment service providers or payment processors.
Deep engineering craft and architectural judgment, including a sense of what is worth codifying and what is a one-off.
AI Fluency Level 4 or the equivalent hands-on experience: you have built agents, skills, evaluations or tooling that other engineers use, and you can explain where human oversight stays non-negotiable.
A systems mindset that turns hard-won knowledge into reusable architecture and tooling rather than documentation.
Comfort with influence as your main way of getting things done, working with builders, product managers, principals and senior leaders without anyone reporting to you.
Nice to have
Experience in hospitality, travel or another operationally complex B2B SaaS environment.
Experience publishing or speaking externally about your work.
A track record of coaching other engineers and multiplying their effectiveness.
Spain
€79.500—€98.200 EUR
Czechia
1 491 000 Kč—1 954 000 Kč CZK
UK
£81,000—£103,200 GBP
Netherlands
$86,500—$104,700 USD
Ireland
$91,000—$114,400 USD