Senior Kotlin Engineer

Hackajob Ltd; Leeds; Hybrid; GBP 90,000 - 110,000; Full time

Benefits offered by this job

Equity

Hybrid working

Lunch program

Training budget

10% time for engineers

Health coverage

Retirement savings

Referral bonuses

Job summary

Hackajob Ltd in the United Kingdom (Leeds area) is seeking an experienced Kotlin engineer to design, build, and integrate APIs for our collections platform. You will create internal tools and collaborate closely with stakeholders across the business to deliver robust backend solutions.

You will work with modern architectures, write clean, tested code, and contribute to expanding new products and services in the US, all within a hybrid working model and a supportive engineering culture.

Qualifications

• Strong Kotlin experience and ability to write clean, testable code.
• Relational databases are a must; NoSQL is a plus.
• Ability to understand complex financial business domains.
• Experience with various software architectures and abstractions.
• Familiarity with the testing pyramid and automated tests across levels.
• Knowledge of Kanban as an agile workflow.

Responsibilities

• Build and integrate new APIs to support our collections function.
• Create new internal tools.
• Support expansion of new products and services in the US.
• Contribute to design discussions and architecture decisions.
• Deliver idiomatic Kotlin solutions to engineering challenges.
• Collaborate with stakeholders across the business.
• Help improve engineering capabilities as a team.
• Participate in interview stages and technical walkthroughs.

Skills

Kotlin experience

Clean code

Relational databases

Financial domain understanding

Software architectures

Abstraction & interpolation

Testing pyramid

Kanban

Tools

Docker

Kubernetes

GraphQL

JUnit

Gradle

RabbitMQ

React

React Native

Job description

Salary: £100,000 - 100,000 per year

Requirements:

• Strong commercial Kotlin experience
• Ability to write simple, clean code
• Experience and understanding of databases; relational databases are a must, and NoSQL would be an advantage
• Ability to quickly understand complex financial business domains
• Ability to understand different software architectures rapidly
• Understanding of abstraction and interpolation
• Ability to write comprehensive automated tests at all levels of the pyramid
• Understanding of the Kanban agile methodology is an advantage

Responsibilities:

• Build and integrate new APIs to support our collections function
• Create new internal tools
• Support our expansion of new products and supporting services in the US
• Contribute to collaborative design discussions and architecture decisions
• Deliver elegant, idiomatic Kotlin solutions to complex engineering challenges
• Work closely with stakeholders across the business
• Help improve our engineering capabilities as a team
• Participate in interview stages including coding exercise discussion, architecture/design exercises, and technical walkthroughs

Technologies:

• Support
• Kanban
• Kotlin
• NoSQL
• AI
• API
• AWS
• Backend
• Cloud
• DevOps
• Docker
• Frontend
• GitHub
• Gradle
• GraphQL
• JUnit
• Kubernetes
• Machine Learning
• RabbitMQ
• React
• React Native
• Redux
• SASS
• TypeScript

More:

We are Lendable, a fast-growing fintech company on a mission to build the worlds best technology to help people get credit and save money. We are one of the UKs newest unicorns, profitable since 2017, backed by top investors including Balderton Capital and Goldman Sachs, and loved by customers with a 4.9 Trustpilot rating across tens of thousands of reviews. Our engineering team is around 80 strong and has rebuilt major consumer finance products from scratch, and we are continuing to launch new products. We offer a collaborative, people-first environment with a broad remit, small teams, and a focus on ownership, learning, and pragmatic delivery. Benefits include best-in-class compensation with equity, hybrid working with home working on Mondays and Fridays, in-house chef-prepared lunches on in-office days, training budget, 10% time for engineers, active guilds, health coverage, retirement and savings support, employee referral bonuses, and office meals and snacks, with details varying by location and role.

last updated 40 week of 2026