Senior Backend Engineer

About Tembo At Tembo, we’re building the UK’s leading consumer mortgage platform, helping people buy their first home, remortgage, and move up the property ladder. Home ownership has become increasingly difficult for many people. Through innovative mortgage products, affordability schemes, and savings tools such as our Lifetime ISA and Cash ISA, Tembo helps families who might otherwise be locked out of home ownership. Our platform supports the entire journey, from mortgage discovery through to application submission, alongside savings products that help people build towards buying a home. We’re rated 4.8★ on Trustpilot, with thousands of customers whose lives have been changed by getting onto the property ladder. Our biggest challenge this year is scale. We aim to double the number of mortgage cases we submit without doubling the size of our operations team. Achieving that requires us to automate large parts of the mortgage journey through operational tooling, workflow automation, AI, and integrations with lenders and financial partners. The Role We’re looking for a Senior Backend Engineer to build and own systems that power Tembo’s mortgage and savings platform. This is a hands-on engineering role focused on designing, writing, shipping, and operating production software. You’ll work on complex financial workflows, operational tooling, and integrations with lenders and partners. You’ll work closely with engineering, product, and operations to understand problems, contribute to technical approaches, and turn them into reliable software. You’ll take ownership of the systems you build, from initial design through to production operation and ongoing improvement. We’re looking for someone who can work independently, make sound technical decisions, and collaborate well with others. You’ll contribute to architecture discussions and engineering quality through your own work, code reviews, and pairing. What Engineers at Tembo Build Examples of systems our engineers work on include: AI-assisted mortgage workflow automation that moves cases through lender processes with minimal manual interventionOperational tooling used by Tembo’s case management teamsIntegrations with lenders, credit agencies, and financial partnersSavings infrastructure powering products such as our Cash ISA and Lifetime ISAAutomation systems that remove operational bottlenecks throughout the mortgage journey These systems are central to enabling Tembo to scale while maintaining a high-quality customer experience. Examples of Problems We’re Working On Applying AI to automate parts of the mortgage workflowIncreasing mortgage case throughput through workflow automationBuilding internal tools for operations teams managing large numbers of casesBuilding reliable integrations with lenders and financial institutionsScaling Tembo’s mortgage platform as customer demand growsEnsuring correctness and auditability in savings products handling real customer fundsImproving observability and reliability across the platformEvolving existing systems while continuing to deliver product improvements What You’ll Do Design and build backend systems Design, implement, and ship services that power Tembo’s mortgage and savings platform. You’ll write production code throughout the week and take ownership of substantial features and systems. Own systems end-to-end Take responsibility for the systems you work on, including data modelling, implementation, deployment, monitoring, reliability, performance, and ongoing maintenance. Turn problems into deliverable work Work with engineering and product colleagues to turn customer and business problems into practical technical solutions. Break your work into deliverable pieces, provide pragmatic estimates, and surface uncertainty, risks, and dependencies early. Automate operational workflows Work closely with product and operations teams to understand manual processes and build systems that improve efficiency, accuracy, and customer outcomes. Improve the codebase Improve the structure and maintainability of the code you work on. Make pragmatic decisions about technical debt and choose approaches that balance simplicity, reliability, and delivery speed. Contribute to engineering quality Participate in architecture discussions, code reviews, and pairing. Share your knowledge and help improve our testing, documentation, observability, and approach to operating production systems. What Success Looks Like Within your first 6–12 months, you will likely have: Designed, built, and launched systems that increase mortgage case throughputDelivered automation that removes manual steps from the mortgage workflowBuilt operational tooling used daily by Tembo’s case management teamsTaken ownership of important parts of the mortgage or savings platformImproved the reliability, observability, and maintainability of the services you work onBuilt a strong understanding of the codebase and effective working relationships across engineering, product, and operationsDelivered substantial work while communicating progress, trade-offs, and risks clearly What We’re Looking For We’re looking for an experienced engineer who enjoys building systems, taking ownership, and solving problems with others. You likely have: 5+ years of experience building and operating production backend systemsExperience designing, delivering, and owning production systems end-to-endStrong experience with Ruby on Rails or a similar backend frameworkExperience working with transactional, financial, or operationally critical systemsStrong knowledge of data modelling and system designExperience operating services in production, including monitoring, debugging, performance, and reliabilityThe ability to turn ambiguous requirements into practical technical solutionsSound judgement about when to invest in architecture and when to choose a simpler approachThe communication skills to work effectively with engineering, product, and operations colleagues We’re particularly interested in engineers who have taken responsibility for how their systems work in production and the outcomes they deliver. Nice to have Experience with payments or financial infrastructureExperience building workflow automation systemsExperience applying AI to operational or customer-facing workflowsExperience building internal platforms or operational toolingExperience with ledger, reconciliation, or audit-sensitive systemsExperience working in a fast-growing startup or scale-up environment This Role Might Not Be the Right Fit If You’re looking to move away from writing production codeYour experience is primarily frontend or product-focused full-stack workMost of your backend work has involved straightforward CRUD applicationsYou prefer fully defined implementation tasks over helping determine the solutionYou haven’t yet had the opportunity to design, deliver, and operate systems end-to-end Our Tech Stack Our backend platform is primarily built with: Ruby on RailsPostgreSQLAWSOpenTelemetryOpenAPI We value strong engineering fundamentals, sound judgement, and system design ability more than experience with any specific technology. Why Join Tembo Your work at Tembo will directly affect how people get onto the property ladder. You’ll work closely with engineering, product, and operations on problems that are central to the company’s growth. You’ll have room to influence technical decisions, own meaningful systems, and see the impact of your work on customers and colleagues. This is an opportunity to stay deeply hands-on while building software that makes complex financial processes simpler and more reliable. Benefits Remote-first workingPrivate health insuranceEnhanced parental benefitsBirthday day offAnnual international team offsiteCompetitive salary and equity Our Values Find a way We innovate relentlessly to help customers get onto the property ladder. It’s all about the people Customers, colleagues, and partners are at the heart of everything we do. If you don’t like it, change it We move quickly, listen to feedback, and evolve constantly. Application As part of the application process, we’ll ask you to describe a system you have helped design, delivered, and owned in production. We’ll be particularly interested in your contribution, the decisions you made, the trade-offs you considered, how you worked with others, and what you learned from operating it in the real world.