Software Engineer - Full Stack

Mast is on a mission to make complex lending simple. The UK's specialist lending market is underserved by technology, with legacy systems that can't handle the nuance of complex income, niche products, or the broker workflows that specialist lenders rely on. We're building modern, cloud-native lending technology, purpose-built for specialist lenders, that helps them process more applications in less time, reach decisions faster, and deliver better experiences for brokers and borrowers. We're pioneering the use of AI in mortgage origination, building it into the platform from the ground up rather than bolting it onto legacy architecture.. We work with regulated lenders across the UK, have a 100% delivery track record, and are building a high-performance team where everyone has real ownership and direct impact. Responsibilities You'll work closely with team to support the engineering effort on the Mast mortgage origination platform. We're growing the team to be able to ship more features and onboard more clients. But we're still a small team, so everyone's expected to pitch in to all parts of the product and engineering lifecycle. We’re looking for someone who thrives under pressure, moves fast, and delivers with urgency. We rely heavily on Rails, Vue3 for more complex front-end pieces, Heroku for our infrastructure, and AWS. Our interview process is an initial phone screen, a take-home code task, and a half-day on-site (or remote) pairing session. We promise not to ask you any trick questions or make you code on a whiteboard! Work with the engineering team to ideate on and build the Mast platform Write thoughtful, high-quality code – using TDD where possible Proactively maintain and improve our codebase Support product improvement drives and independently identify potential product improvements Build the front-end of applications through appealing visual design Work on integrations with other potential partners and on APIs Troubleshoot, debug and upgrade software Learn and understand our infra stack - Heroku + AWS Build systems to automate as much of the developer experience as possible Requirements 6+ years experience in web application design and development Strong experience with Rails, which is at the core of our tech stack. Experience with JS front-end frameworks is a bonus, especially Vue3 Strong experience creating and deploying complex web applications that are scalable, manageable and performant Willingness to pair program regularly! When you join you'll get a Tuple account for seamless remote pairing Comfortable using AI tools as part of your development workflow Experience writing automated unit, integration and end-to-end tests in RSpec Working knowledge of Unix-like operating systems Ability to work independently in a team environment Self-directed with strong execution skills • Work digital-first in your daily life Desirable Experience of pairing, Agile, TDD Knowledge of banking/finance/fintech Previous startup/scale-up experience Cloud computing experience Infrastructure as code experience Experience with DevOps culture and teams owning their infrastructure Willingness to learn new technologies in a fast-paced startup environment. Excellent communication skills to work across teams. • A pragmatic mindset, focusing on solutions that drive efficiency. Salary Range £80,000 - £90,000 + Stock Options Please note that we are unable to sponsor visa applications at this time. Benefits Stock Option Plan 25 days holiday + bank holidays 4 - 10 weeks work from anywhere, based on tenure (for UK based roles) Vitality Health insurance Pension plan Equipment budget Learning & development budget Cycle to Work Scheme Monthly team socials + Quarterly Team Meet-ups @ HQ Digital-first, employee-first company with a flexible working culture + Central London HQ About Us Mast is a high-performance team of engineers and lending experts building the future of specialist lending technology. We value radical honesty, transparency, and speed. We hire exceptional people, expect a lot from each other, and offer real ownership, fast growth, and the chance to shape an industry. Mast. is an equal opportunity employer and we celebrate diversity and are committed to creating an inclusive environment for all employees.