Senior Kotlin Engineer

Hackajob Ltd; City of Westminster; Hybrid; GBP 90,000 - 110,000; Full time

Benefits offered by this job

Equity

Hybrid work

Lunch program

Training budget

Engineer time (10%)

Health coverage

Retirement & savings

Job summary

Hackajob Ltd. is seeking a senior software engineer to deliver elegant Kotlin solutions and robust APIs in a fast-growing fintech environment. You will collaborate with stakeholders and contribute to architectural decisions while supporting new product initiatives across the US market.

The role emphasizes strong testing, clean code, and rapid learning of financial domains, with a hybrid setup and opportunities for ownership and growth.

Qualifications

• Strong commercial Kotlin experience.
• Ability to write simple, clean code.
• Experience with relational databases; NoSQL as plus.
• 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 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.

Skills

Kotlin experience

Clean code

Financial domain understanding

Software architectures

Abstraction & interpolation

Automated tests

Kanban knowledge

Tools

Kotlin

NoSQL

AI

API

AWS

Backend

Cloud

DevOps

Docker

Frontend

GitHub

Gradle

GraphQL

JUnit

Kubernetes

Machine Learning

RabbitMQ

React

React Native

Redux

SASS

TypeScript

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 36 week of 2026