Lead Back-End Developer - Java

Segmentify; Greater London; On-site; GBP 90,000 - 120,000; Full time

Job summary

Segmentify, a data-driven e-commerce personalization platform, seeks a lead back-end developer to own the backend stack. You will craft RESTful services, design data APIs, and scale microservices to process billions of events daily with near real-time performance.

Collaboration with product and data science teams is essential to translate business needs into robust software. The role requires deep Java expertise (Spring, REST), experience with distributed systems and NoSQL/databases, and a focus

Qualifications

• BSc or MSc 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 preferred)
• Strong experience with In Memory Database and Caches (Ignite and Redis preferred)
• Scalable and distributed web app experience (Reactive programming and Spring Reactor preferred)
• Experience with microservice architectures
• Experience with CI/CD pipelines
• NoSQL experience (MongoDB and/or Cassandra preferred)
• Hands-on with event-driven architectures and frameworks (Flink, Kafka Streams, Esper)
• Knowledge of design patterns in OO
• Experience with multi-region cloud deployments is a plus
• Familiarity with recommendation algorithms, ranking, personalization, or ML integration

Responsibilities

• Develop RESTful services to handle high-volume online retail traffic with microservices architecture
• Turn user stories into functional web applications using Java and Spring Boot
• Design and implement data APIs and services for other apps to consume
• Implement Big Data solutions processing billions of events per day with near real-time SLAs
• Collaborate with product and data science teams to align solutions with business goals
• Deliver modular, testable, and scalable backend services across the lifecycle

Skills

Java

Spring Boot

REST APIs

Microservices

Distributed systems

SQL/PostgreSQL

NoSQL MongoDB/Cassandra

Kafka/Streams

Elasticsearch/OpenSearch

Observability

Education

Bachelor's or Master's in CS/Engineering

Tools

Redis

Ignite

Git

CI/CD

AWS/GCP

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