Senior Full Stack Developer – Java, Spring Boot & Angular

About Us California Software Company Limited (Calsoft) is a publicly listed technology company building AI-powered enterprise SaaS products for businesses. Our flagship products include Flowzo CRM, CallSync, WhatsApp CRM, and Reach (Sales Sequencing Platform). We are looking for a passionate and hands-on Technical Lead / Senior Full Stack Developer to design, develop, and enhance scalable enterprise applications using modern Java technologies.

Key Responsibilities

• Design, develop, and maintain enterprise applications using Java and Spring Boot.
• Build scalable REST APIs and microservices.
• Develop modern, responsive user interfaces using Angular.
• Implement Redis caching to improve application performance.
• Build Kafka-based event-driven and asynchronous processing systems.
• Integrate third-party services such as WhatsApp Business API, telephony platforms, payment gateways, email, SMS, OAuth, and other enterprise APIs.
• Optimize application performance, scalability, and security.
• Design efficient database structures and optimize SQL queries.
• Participate in architecture discussions and technical decision-making.
• Conduct code reviews and mentor junior developers.
• Collaborate with Product, QA, DevOps, and UI/UX teams to deliver high-quality software.
• Troubleshoot production issues and provide long-term technical solutions.

Required Technical Skills Backend Java 8/17/21 Spring Boot Spring MVC Spring Security Spring Data JPA Hibernate REST APIs Microservices

Frontend Angular (latest versions preferred) TypeScript HTML5 CSS3 JavaScript

Database PostgreSQL / MariaDB / MySQL SQL Query Optimization

Messaging & Caching Kafka Redis

DevOps & Tools Git Maven / Gradle Docker Linux CI/CD Pipelines

Preferred Skills Experience with one or more of the following: WhatsApp Business API SIP / Asterisk / FreeSWITCH WebRTC Call Recording Click-to-Call Voice APIs AI integrations (OpenAI, Claude, Gemini, etc.) Docker & Kubernetes Elasticsearch/OpenSearch RabbitMQ

Desired Candidate Profile We are looking for someone who:

• Has 5–9 years of hands-on experience in Java and Spring Boot development.
• Has strong experience with Angular development.
• Has built scalable enterprise or SaaS applications.
• Has experience integrating multiple third-party APIs.
• Demonstrates strong analytical and critical-thinking skills.
• Can independently design and implement technical solutions.
• Has experience mentoring developers and performing code reviews.
• Is comfortable working in a fast-paced product development environment.
• Has experience handling production issues and performance optimization.

Preferred Industry Experience Candidates from product-based companies working in CRM, SaaS, Telephony, CPaaS, Contact Center, FinTech, HealthTech, Logistics, or Enterprise Software will be preferred.

Why Join Us? Work on cutting-edge CRM, telephony, and AI-powered enterprise products. Exposure to modern technologies such as Java, Spring Boot, Angular, Redis, Kafka, and AI integrations. Opportunity to contribute to architecture and product innovation. Collaborative engineering culture with continuous learning and career growth.