Senior Java Engineer

United States Digital Space LLC; Singapore; On-site; SGD 90,000 - 150,000; Full time

Job summary

United States Digital Space LLC in Singapore is seeking a strong Mid or Senior Java Engineer to shape and scale the backend of KaiKai Lock Screen and CMS, serving millions of users daily.

You will design, develop, and maintain backend services, build scalable data processing, contribute to architecture, ensure code quality, and collaborate with Product, Content, and Data teams to deliver impactful features.

Qualifications

• Proven experience in Java backend development.
• Skilled at building scalable, high-performance backend systems.
• Familiar with event-driven architectures using Kafka.
• Strong knowledge of relational databases and SQL.
• Ability to own projects and drive solutions.
• Excellent communication in Polish and English.

Responsibilities

• Design, develop, and maintain backend services for KaiKai Lock Screen and CMS.
• Build scalable systems for large-scale data processing and real-time content delivery.
• Contribute to architecture and system design improvements.
• Maintain high code quality through testing, code reviews, and engineering best practices.
• Work with distributed and event-driven systems to build scalable backend solutions.
• Improve system performance, reliability, and efficiency for a high-traffic product.
• Support integrations with external services and third-party systems.
• Collaborate closely with Product, Content, and Data teams to deliver meaningful features.
• Share knowledge and contribute to continuous team improvement.

Skills

Java backend

Scalable systems

Kafka event-driven

SQL databases

Ownership

Polish & English

High-traffic experience

Tools

Kafka

Job description

Job Overview

We’re looking for a strong Mid OR Senior Java Engineer to shape and scale the backend of our core product, KaiKai Lock Screen, used by millions of users every day.

We’re looking for someone who:

• Dreams Big: ambitious, passionate, and out to achieve massive goals
• Customer‑centric: we care about our customers and strive to provide them with the best solutions
• Celebrates both Success & Failure: rejoicing the wins but also reflecting, learning & improving proactively when there are defeats
• Honesty and Integrity: we appreciate respectful feedback
• Problem Solver: you’re a fixer and not a complainer
• Actionable: work and make smart decisions fast with conviction

What you’ll do:

• Design, develop, and maintain backend services for KaiKai Lock Screen and CMS
• Build scalable systems for large‑scale data processing and real‑time content delivery
• Contribute to architecture and system design improvements
• Maintain high code quality through testing, code reviews, and engineering best practices
• Work with distributed and event‑driven systems to build scalable backend solutions
• Improve system performance, reliability, and efficiency for a high‑traffic product
• Support integrations with external services and third‑party systems
• Collaborate closely with Product, Content, and Data teams to deliver meaningful features
• Share knowledge and contribute to continuous team improvement

What you’ll need:

• Strong experience in Java backend development
• Experience building scalable and high‑performance backend systems
• Familiarity with event‑driven systems (Kafka) and modern architectures
• Knowledge of relational databases and SQL
• Ability to take ownership and drive solutions
• Good communication within the team (Polish and English required)
• Experience with high‑traffic systems is a plus

What you’ll enjoy:

You’ll work with a seasoned leadership team, backed with expertise across strategic domains, within a culture that values learning, impact, and cross‑functional collaboration.