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# Back End Developer

- **Company:** Intro
- **Location:** Gusendos de los Oteros, Spain (Remote available)
- **Contract:** Permanent contract
- **Skills:** Java (Programming Language), PHP (Programming Language), Application Programming Interfaces (APIs), Artificial Intelligence, Cloud Computing, Code Review, Java Virtual Machine (JVM), Commercial Software, Software Architecture, Software Maintenance, Software Engineering, Backend, Kotlin, Api Design, Software Coding
- **Published:** September 9, 2026
- **Apply:** https://www.buscojobs.com.es/back-end-developer-en-gusendos-de-los-oteros-ID-369250144

## About the Role

At least
5 years of commercial software engineering experience
, with a strong focus on backend development.
Strong commercial experience with
Kotlin and/or Java
.
If you're primarily a Java engineer, you should be
open to working with and developing in Kotlin
.
Previous experience within financial services, ideally FinTech, lending, banking, payments or another regulated financial environment.
Strong experience working with
cloud-based systems
.
Strong understanding of
APIs, services and backend architecture
.
Experience using or working with
AI tools within software engineering
.
Strong coding standards with a focus on building
clean, reliable and maintainable software
.
Comfortable working independently within a
remote product engineering team, Previous experience with
PHP
or a good understanding of the language.
Experience working on
legacy modernisation or technology transformation projects
.
Experience migrating or rebuilding systems from legacy technologies into
Java, Kotlin or modern JVM architectures
.
Experience within a
startup, scale-up or smaller product-led engineering environment

## Description

Senior Backend Engineer - Kotlin/Java | FinTech |Spain | Fully Remote via EORAre you a Backend Engineer looking to work on the modernisation of a growing FinTech platform?We're partnering with a growinglending FinTechbuilding customer-facing financial products at scale. As the platform continues to evolve, they're looking for aSenior Backend Engineerto join the team and help build the next generation of their backend services.Kotlinis becoming an increasingly important part of the engineering stack, but you don't need to already be a Kotlin expert. They're equally interested in strongJava engineerswho understand the JVM ecosystem and are keen to move into Kotlin.This is a hands-on product engineering role where you'll have the opportunity to build new services, contribute to technical decisions and help modernise an existing technology estate.Being a growing FinTech means engineers have genuine ownership. They're looking for someone who enjoys solving problems, working closely with Product and taking responsibility for what they build rather than simply picking up tickets.What you'll be doingDesigning and buildingscalable backend servicesacross a modern financial technology platform.Developing new services primarily usingKotlin.Working across acloud-based environmentand helping build reliable, maintainable systems.Designing and developingAPIs, services and backend architecture.Contributing to the ongoingmodernisation of the platform, including moving functionality from legacy technologies into modern JVM-based services.Working with existing services, including parts of the platform written inPHP.Taking ownership of your work from design through to delivery.Contributing totechnical decisions, code reviews and engineering best practices.Using and engaging withAI toolingas part of modern software engineering workflows.Working closely with Software Engineering, Product and other stakeholders in a small, cross-functional team.What we're looking forAt least5 years of commercial software engineering experience, with a strong focus on backend development.Strong commercial experience withKotlin and/or Java.If you're primarily a Java engineer, you should beopen to working with and developing in Kotlin.Previous experience within financial services, ideally FinTech, lending, banking, payments or another regulated financial environment.Strong experience working withcloud-based systems.Strong understanding ofAPIs, services and backend architecture.Experience using or working withAI tools within software engineering.Strong coding standards with a focus on buildingclean, reliable and maintainable software.Comfortable working independently within aremote product engineering team.Must bebased in Spain with the right to work in Spain.Nice to havePrevious experience withPHPor a good understanding of the language.Experience working onlegacy modernisation or technology transformation projects.Experience migrating or rebuilding systems from legacy technologies intoJava, Kotlin or modern JVM architectures.Experience within astartup, scale-up or smaller product-led engineering environment.Experience specifically withinlending or consumer finance.?Spain - Fully Remote?Full-time employment via Employer of Record (EOR)If you're a Backend Engineer with a strong Java/Kotlin background who wants to work on a modern FinTech platform, contribute to a wider modernisation journey and have genuine ownership over what you build, I'd be keen to speak.Feel free to apply or message me directly for a confidential conversation.


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