Lead Back-End Developer - Java

Segmentify; Greater London; On-site; GBP 70,000 - 90,000; Full time

Job summary

A leading e-commerce personalization platform in the UK seeks a top-notch lead back-end developer. The role involves developing RESTful services and implementing Big Data solutions with strict SLAs. Candidates should have over 10 years of experience in Java development, be proficient with modern web technologies, and good at translating business requirements into technical solutions. This dynamic position requires collaboration with various teams to deliver high-performance applications for online retailers.

Qualifications

• 10+ years of Java Development experience.
• Ability to write SQL, preferably PostgreSQL.
• Experience with RDBMS and in-memory databases.

Responsibilities

• Develop RESTful services for high-volume online traffic.
• Implement Big Data solutions processing billions of events.
• Collaborate with product and data science teams.

Skills

Java Development

RESTful APIs

Spring

SQL

Microservice architectures

Event-driven architectures

Observability

Git

Education

BSc or MSc in Computer Science or related field

Tools

PostgreSQL

MongoDB

Cassandra

Redis

Apache Ignite

Kafka

Solr / Elasticsearch

Job description

London, United Kingdom | Posted on 17/09/2025

Segmentify is an e-commerce personalization platform helping online retailers to optimise their conversion rates by enabling them to deliver a unique shopping experience for each visitor. Segmentify tracks each individual visitor’s behaviour in real-time and offers smart product recommendations by utilising in-house developed AI technology.

We have a dynamic and passionate compact team dedicated to creating a SaaS solution to boost eCommerce revenue. We are selected as one of the 25 Machine Learning Startups to Watch by Forbes magazine. We are one of the fastest growing start-ups in AI based e-commerce solutions with multiple investment rounds and have offices in 5 countries.

Role:

We are looking for a top-notch lead back-end developer who is prominent with modern and distributed web technologies and Machine Learning algorithms. You will be responsible for developing RESTful services to handle high volume online retail traffic with microservices architecture. You should be keen with modern MVC frameworks such as Spring Boot and convert user stories into functional and rock solid web applications; and also design and implement data APIs and services needed for other applications to consume. You will also be responsible for implementing Big Data solutions that should process billions of user interaction events per day in near real-time with strict SLAs (99.9% availability, sub-200ms latency), and run analysis and segmentations on top of them.

We are not looking for just a Java and Sprint Boot developer, but a software engineer that can turn business requirements into technical solutions, and then working products by collaborating with technical architect. We are asking for the ability to challenge architectural decisions constructively, propose alternatives, and guide trade-off discussions. You should have experience in cross-functional collaboration with product and data science teams to align technical solutions with business goals.

You will collaborate with the product team to deliver the micro-services, modules and features throughout the development life cycle. You will be responsible for developing, testing, debugging, and troubleshooting clean, web standards compliant solutions written in Java.

Our Tech Stack includes Java, Spring Boot, Cassandra, MongoDB, Redis, Apache Ignite, Kafka, PostgreSQL, Nginx. (check details from Stack Share Profile )

Requirements

• BSc or MSc degree in Computer Science, Computer Engineering, Software Engineering or related disciplines from reputable universities
  
• 10+ years of Java Development experience (Spring and RESTful APIs)
  
• Proficient with RDBMS and ability to write SQL (PostgreSQL is preferred)
  
• Strong experience with In Memory Database and Caches (Apache Ignite and Redis are preferred)
  
• Scalable and distributed web application experience (Reactive programming and Spring Reactor experience is preferred)
  
• Experience in developing with microservice architectures
  
• Experience with Continuous Integration and Delivery pipelines
  
• NoSQL database experience (MongoDB and/or Cassandra is preferred)
  
• Hands-on experience with event-driven architectures and complex event processing frameworks (e.g. Flink, Kafka Streams, Esper) to derive insights from continuous event streams
• Good knowledge of design patterns and experience in implementing them in object-oriented fashion
  
• Experience designing fault-tolerant, multi-region deployments in cloud environments is a plus
  
• Familiarity with recommendation algorithms, ranking, personalization, or ML integration into production microservices
  
• Hands-on with Solr / Elasticsearch / OpenSearch for large-scale product search is a plus
  
• Strong knowledge and focus on observability (metrics, tracing, profiling) and reliability (SLAs, SLOs)
  
• Good verbal and written communication skills and ability to convert user stories into full functional interfaces and APIs
  
• Proficient in using Git version control and branching methodologies
  
• Proficient in English (TOEFL or IELTS certification is preferred)
  
• Ability to handle multiple tasks simultaneously and meet deadlines