Senior Software Engineer I

Thought Machine's mission is bold – to properly and permanently rid the world's banks of legacy technology. To achieve this, we have developed the foundations of modern banking through core and payments technology which run natively in the cloud. What we are attempting is hard and means we need great people working together to build great technology. We have grown rapidly in the past few years – growing our team to more than 550 individuals across offices in London, New York, Singapore, Sydney and our newly established Engineering Hub in Lisbon. We have raised more than £500m in funding and our investors include Molten Ventures, Eurazeo, Intesa Sanpaolo, Temasek, Nyca Partners, JPMorgan Chase Strategic Investments, Standard Chartered Ventures, and more. We have created a culture that enables our team to produce the best work in the industry while ensuring we have fun along the way. We're regularly cited as having a fantastic workplace culture and have been recognised by Sifted magazine as having one of the highest Glassdoor ratings for a UK fintech company and the industry's most generous employee share package. Named one of the world's most innovative fintechs by Global Finance Magazine, we were also recognised by the Financial Times as one of Europe's fastest-growing companies for two consecutive years—and a UK Best Employer for 2026. As a Senior Software Engineer I at Thought Machine, you will own and deliver highly complex, end-to-end engineering work items. You will look beyond immediate coding tasks to consider long-term system architecture, product strategy, and client outcomes. In this role, you will act as a technical anchor for your team, solving ambiguous problems, guiding less experienced engineers, and actively shaping our technical and product roadmaps. This is a role for an engineer who values clean, maintainable systems, embraces an egoless approach to collaboration, and is driven to deliver robust solutions to production. What You’ll Do Technical Leadership Design & Build: Design and build highly reliable, secure, and scalable software solutions for complex problems. Architecture & Standards: Contribute to team guidelines ensuring our services meet top-tier security, performance, cost, and reliability standards. Code Quality & Peer Review: Set a high bar for code quality by providing constructive, detailed feedback on design documents and pull requests. Operational Excellence: Investigate issues across multiple services in production, drive learning from operational incidents, and feed improvements back into our prioritisation process. Hiring: Actively participate in our growth by leading technical interviews. Product & Delivery End-to-End Ownership: Own work items from initial concept to production, creating structured delivery plans, managing dependencies along the way and owning delivery of these work items. Product Vision: Partner with Product Managers to prioritize features, translate client requirements into technical specifications, and ensure solutions align with our overarching product vision. Incident Management: Confidently own the resolution of incidents, coordinating mitigation, fixes, and post-mortem artifacts. Collaboration & Mentorship Team Growth: Mentor and support less experienced engineers, helping them level up technically and adapt to Thought Machine’s engineering philosophy. Stakeholder Management: Translate highly technical problems and architectural decisions into clear concepts for non-technical stakeholders. What We’re Looking For Technical Expertise: Strong proficiency in modern backend languages (ideally Go or Python) and experience building distributed, cloud-native systems (Kubernetes, AWS/GCP, gRPC, PostgreSQL). Problem Solving: A proven track record of breaking down ambiguous, and complex problems into clear, deliverable milestones. Production Operations: Experience supporting high-throughput systems in production environments and diagnosing complex issues across distributed systems. Egoless Collaboration: A highly collaborative, feedback-receptive mindset focused on finding the best outcomes for our clients and business rather than defending personal preferences. Communication: Excellent written and verbal communication skills, with the ability to build consensus and document technical designs clearly. Benefits Highly competitive salary Pension plan (match up to 5%) Life insurance - three times annual salary Competitive maternity (six months fully paid) and paternity leave (four weeks fully paid) Shared parental leave (matched to our maternity leave for the same point in time) 25 days holiday and bank holidays Flexible working hours Cycle-to-work scheme Electric car scheme Season ticket loan Access to outstanding learning materials and courses Sports and hobby clubs, subsidised by Thought Machine All the latest tech you need Start the day properly with fresh fruit and cereals Huge range of healthy (and not-so-healthy) snacks, smoothies and drinks A talented and experienced team as your colleagues An environment where we encourage learning and progress Two charity days a year Weekly food pop-up We actively hire candidates who demonstrate technical excellence in their field and welcome people of all ages and backgrounds, providing everyone with equal access to professional development. You are encouraged to apply even if your experience doesn't accurately match the job description. We also encourage applications from those with different abilities, including candidates with ADHD, autism, dyslexia or dyspraxia. We actively hire candidates who demonstrate technical excellence in their field and welcome people of all ages and backgrounds, providing everyone with equal access to professional development. You are encouraged to apply even if your experience doesn't accurately match the job description. We also encourage applications from those with different abilities, including candidates with ADHD, autism, dyslexia or dyspraxia.