Backend Engineer

PT Leap Digital Indonesia; Jakarta Pusat; On-site; IDR 420,000,000 - 640,000,000; Full time

Job summary

PT Leap Digital Indonesia is seeking an experienced Backend Engineer to design and maintain scalable backend services for an omnichannel clienteling platform. You will build microservices with Java and Spring Boot, implement messaging with Kafka, and optimize data models in PostgreSQL and MongoDB.

You will enable real-time features with WebSockets, ensure security with RBAC/ABAC and OAuth2/JWT, integrate with external platforms, and participate in code reviews, CI/CD, and production support

Qualifications

• Minimum 4 years of backend development experience, including production experience with Java and Spring Boot.
• Strong proficiency in Java 21 and Spring Boot 4.
• Strong knowledge of PostgreSQL, including schema design, query optimization, indexing, and connection pooling.
• Production experience with Redis and Kafka.
• Experience with WebSockets or other long-lived connection systems at scale.
• Strong understanding of concurrency, idempotency, distributed locking, and consistency trade-offs in microservices.
• Experience with Spring Security, OAuth2 / JWT, and implementing RBAC or ABAC.
• Experience with Docker, Kubernetes or ECS, CI/CD pipelines, and AWS or GCP.
• Experience writing unit and integration tests using JUnit and Testcontainers.
• Ability to troubleshoot production issues, including memory leaks, slow queries, thread contention, and slow downstream dependencies.
• Familiarity with Git workflows, including branching, pull request reviews, and conflict resolution.

Responsibilities

• Develop and maintain backend services using Java and Spring Boot for conversation management, message routing, campaigns, and sales attribution.
• Design and optimize data models across PostgreSQL and MongoDB.
• Build event-driven architectures using Kafka, including message ordering, retries, and error handling.
• Develop and maintain integrations with the W Business Platform, including message handling, webhooks, templates, and delivery status tracking.
• Implement phone number normalization and matching to link incoming WhatsApp messages with customer records.
• Integrate chatbot, VoIP, and Microsoft Graph services, including bot-to-human handoff workflows.
• Implement real-time messaging using WebSockets and ensure horizontal scalability across multiple instances.
• Optimize backend services to support thousands of concurrent users while meeting performance and availability targets.
• Implement access control mechanisms using RBAC or ABAC, alongside customer data masking.
• Ensure secure handling of personal data in accordance with Indonesia's Personal Data Protection Law (UU No 27/2022), including audit logging.
• Estimate tasks, manage development priorities, and deliver work according to agreed timelines.
• Implement observability through logging, metrics, and distributed tracing.
• Troubleshoot production issues, participate in code reviews, and collaborate with frontend, BA, QA, and vendor teams.

Skills

Ownership

Troubleshooting

Communication

Problem-solving

Education

Bachelor's degree in Computer Science, Information Technology, or related field

Tools

Java

Spring Boot

PostgreSQL

MongoDB

Kafka

WebSockets

RBAC/ABAC

Spring Security

OAuth2/JWT

Docker

Kubernetes

CI/CD

AWS

GCP

JUnit/Testcontainers

Git workflows

Redis

Job description

We are seeking an experienced Backend Engineer to develop and maintain scalable backend services for an omnichannel clienteling platform. The role will involve building microservices, integrating messaging systems and third-party platforms, and ensuring system performance, reliability, and security.

Responsibilities

Develop and maintain backend services using Java and Spring Boot for conversation management, message routing, campaigns, and sales attribution.

Design and optimize data models across PostgreSQL and MongoDB.

Build event-driven architectures using Kafka, including message ordering, retries, and error handling.

2. Integration & Messaging

Develop and maintain integrations with the W Business Platform, including message handling, webhooks, templates, and delivery status tracking.

Implement phone number normalization and matching to link incoming WhatsApp messages with customer records.

Integrate chatbot, VoIP, and Microsoft Graph services, including bot-to-human handoff workflows.

3. Scalability & Performance

Implement real-time messaging using WebSockets and ensure horizontal scalability across multiple instances.

Optimize backend services to support thousands of concurrent users while meeting performance and availability targets.

4. Security & Data Protection

Implement access control mechanisms using RBAC or ABAC, alongside customer data masking.

Ensure secure handling of personal data in accordance with Indonesia's Personal Data Protection Law (UU No 27/2022), including audit logging.

5. Delivery & Production Support

Estimate tasks, manage development priorities, and deliver work according to agreed timelines.

Implement observability through logging, metrics, and distributed tracing.

Troubleshoot production issues, participate in code reviews, and collaborate with frontend, Business Analyst (BA), QA, and vendor teams.

Qualifications

Must-Have Requirements

Minimum 4 years of backend development experience, including production experience with Java and Spring Boot.

Strong proficiency in Java 21 and Spring Boot 4.

Strong knowledge of PostgreSQL, including schema design, query optimization, indexing, and connection pooling.

Production experience with Redis and Kafka.

Experience with WebSockets or other long-lived connection systems at scale.

Strong understanding of concurrency, idempotency, distributed locking, and consistency trade-offs in microservices.

Experience with Spring Security, OAuth2 / JWT, and implementing RBAC or ABAC.

Experience with Docker, Kubernetes or ECS, CI/CD pipelines, and AWS or GCP.

Experience writing unit and integration tests using JUnit and Testcontainers.

Ability to troubleshoot production issues, including memory leaks, slow queries, thread contention, and slow downstream dependencies.

Familiarity with Git workflows, including branching, pull request reviews, and conflict resolution.

Bachelor's degree in Computer Science, Information Technology, or a related field.

Preferred Qualifications

Production experience with the WhatsApp Business Platform, including Cloud API or a Business Solution Provider (BSP) such as Twilio, Infobip, Qiscus, or Mekari Qontak.

Experience with contact center, customer service, helpdesk, ticketing, or live chat platforms, particularly message routing, queue management, and SLA tracking.

Experience using MongoDB for high-volume message storage.

Familiarity with SIP / WebRTC signaling or VoIP integrations.

Experience integrating chatbot or conversational AI platforms, including human-handoff workflows.

Key Attributes

Strong ownership and accountability in delivering backend solutions.

Excellent problem-solving and troubleshooting skills.

Strong attention to detail and commitment to code quality.

Clear communication skills for asynchronous collaboration with distributed teams and external vendors.

Ability to work collaboratively with cross-functional teams to deliver reliable, scalable solutions.