Java Backend Developer

JOB DESCRIPTION

Experience: 5-8 years

Location: Mumbai

Wissen Technology is now hiring for a Java Developer - Bangalore with hands-on experience in Core Java, algorithms, data structures, multithreading and SQL. We are solving complex technical problems in the industry and need talented software engineers to join our mission and be a part of a global software development team. A brilliant opportunity to become a part of a highly motivated and expert team which has made a mark as a high-end technical consulting. 

Required Skills:

• Exp. - 5-8 years
• Experience in Core Java and Spring Boot.
• Extensive experience in developing enterprise-scale applications and systems. Should possess good architectural knowledge and be aware of enterprise application design patterns.
• Should have the ability to analyze, design, develop and test complex, low-latency client- facing applications.
• Good development experience with RDBMS.
• Good knowledge of multi-threading and high-performance server-side development.
• Basic working knowledge of Unix/Linux.
• Excellent problem solving and coding skills.
• Strong interpersonal, communication and analytical skills.
• Should have the ability to express their design ideas and thoughts.

Company Description

NonStop io Technologies, founded in August 2015, is a Bespoke Engineering Studio specializing in Product Development. With over 80 satisfied clients worldwide, we serve startups and enterprises across prominent technology hubs, including San Francisco, New York, Houston, Seattle, London, Pune, and Tokyo. Our experienced team brings over 10 years of expertise in building web and mobile products across multiple industries. Our work is grounded in empathy, creativity, collaboration, and clean code, striving to build products that matter and foster an environment of accountability and collaboration.

Responsibilities:

● Develop and Maintain: Write clean, efficient, and maintainable code for Java-based applications 

● Collaborate: Work with cross-functional teams to gather requirements and translate them into technical solutions 

● Code Reviews: Participate in code reviews to maintain high-quality standards 

● Troubleshooting: Debug and resolve application issues in a timely manner 

● Testing: Develop and execute unit and integration tests to ensure software reliability

● Optimize: Identify and address performance bottlenecks to enhance application performance 

Qualifications & Skills:

● Strong knowledge of Java, Spring Framework (Spring Boot, Spring MVC), and Hibernate/JPA 

● Familiarity with RESTful APIs and web services

● Familiarity with Mirth Connect for building, managing, and supporting integrations 

● Proficiency in working with relational databases like MySQL or PostgreSQL 

● Practical experience with AWS cloud services and building scalable, microservices-based architectures

● Experience with build tools like Maven or Gradle 

● Understanding of version control systems, especially Git 

● Strong understanding of object-oriented programming principles and design patterns 

● Familiarity with automated testing frameworks and methodologies 

● Excellent problem-solving skills and attention to detail 

● Strong communication skills and ability to work effectively in a collaborative team environment

● Ready to be a tech-agnostic engineer and comfortable to shift on any tech stack (Java, Node, Python etc)

● Comfortable working with AI (Claude code, Cursor etc)

Why Join Us? 

● Opportunity to work on cutting-edge technology products 

● A collaborative and learning-driven environment 

● Exposure to AI and software engineering innovations 

● Excellent work ethic and culture 

If you're passionate about technology and want to work on impactful projects, we'd love to hear from you

Review Criteria

• Strong Senior Backend Engineer profiles
• Must have 5+ years of hands-on Backend Engineering experience building scalable, production-grade systems
• Must have strong backend development experience using one or more frameworks (FastAPI / Django (Python), Spring (Java), Express (Node.js).
• Must have deep understanding of relevant libraries, tools, and best practices within the chosen backend framework
• Must have strong experience with databases, including SQL and NoSQL, along with efficient data modeling and performance optimization
• Must have experience designing, building, and maintaining APIs, services, and backend systems, including system design and clean code practices
• Experience with financial systems, billing platforms, or fintech applications is highly preferred (fintech background is a strong plus)
• (Company) – Must have worked in product companies / startups, preferably Series A to Series D
• (Education) – Candidates from top engineering institutes (IITs, BITS, or equivalent Tier-1 colleges) are preferred

Role & Responsibilities

As a Founding Engineer at company, you'll join our engineering team during an exciting growth phase, contributing to a platform that handles complex financial operations for B2B companies. You'll work on building scalable systems that automate billing, usage metering, revenue recognition, and financial reporting—directly impacting how businesses manage their revenue operations.

This role is perfect for someone who thrives in a dynamic startup environment where requirements evolve quickly and problems need creative solutions. You'll work on diverse technical challenges, from API development to external integrations, while collaborating with senior engineers, product managers, and customer success teams.

Key Responsibilities-

• Build core platform features: Develop robust APIs, services, and integrations that power company’s billing automation and revenue recognition capabilities
• Work across the full stack: Contribute to both backend services and frontend interfaces, ensuring seamless user experiences
• Implement critical integrations: Connect company with external systems including CRMs, data warehouses, ERPs, and payment processors
• Optimize for scale: Build systems that handle complex pricing models, high-volume usage data, and real-time financial calculations
• Drive quality and best practices: Write clean, maintainable code while participating in code reviews and architectural discussions
• Solve complex problems: Debug issues across the stack and work closely with teams to address evolving client needs

The Impact You'll Make-

• Power business growth: Your code will directly enable billing and revenue operations for fast-growing B2B companies, helping them scale without operational bottlenecks
• Build critical financial infrastructure: Contribute to systems handling millions in transactions while ensuring accurate, compliant revenue recognition
• Shape product direction: Join during our scaling phase where your contributions immediately impact product evolution and customer success
• Accelerate your expertise: Gain deep knowledge in financial systems, B2B SaaS operations, and enterprise software while working with industry veterans
• Drive the future of B2B commerce: Help create infrastructure powering next-generation pricing models from usage-based to value-based billing.

Company Name – Wissen Technology

Group of companies in India – Wissen Technology & Wissen Infotech

Work Location - Senior Backend Developer – Java (with Python Exposure)- Mumbai

Experience - 4 to 10 years

Kindly revert over mail if you are interested.

Java Developer – Job Description

We are seeking a Senior Backend Developer with strong expertise in Java (Spring Boot) and working knowledge of Python. In this role, Java will be your primary development language, with Python used for scripting, automation, or selected service modules. You’ll be part of a collaborative backend team building scalable and high-performance systems.

Key Responsibilities

• Design and develop robust backend services and APIs primarily using Java (Spring Boot)
• Contribute to Python-based components where needed for automation, scripting, or lightweight services
• Build, integrate, and optimize RESTful APIs and microservices
• Work with relational and NoSQL databases
• Write unit and integration tests (JUnit, PyTest)
• Collaborate closely with DevOps, QA, and product teams
• Participate in architecture reviews and design discussions
• Help maintain code quality, organization, and automation

Required Skills & Qualifications

• 4 to 10 years of hands-on Java development experience
• Strong experience with Spring Boot, JPA/Hibernate, and REST APIs
• At least 1–2 years of hands-on experience with Python (e.g., for scripting, automation, or small services)
• Familiarity with Python frameworks like Flask or FastAPI is a plus
• Experience with SQL/NoSQL databases (e.g., PostgreSQL, MongoDB)
• Good understanding of OOP, design patterns, and software engineering best practices
• Familiarity with Docker, Git, and CI/CD pipelines

• 2.5+ year of experience in Development in JAVA technology.
• Strong Java Basics
• SpringBoot or Spring MVC
• Hands on experience on Relationl Databases (SQL query or Hibernate) + Mongo (JSON parsing)
• Proficient in REST API development
• Messaging Queue (RabitMQ or Kafka)
• Microservices
• Any Caching Mechanism
• Good at problem solving

Good to Have Skills:

• 2+ years of experience in using Java/J2EE tech stacks
• Good understanding of data structures and algorithms.
• Excellent analytical and problem solving skills.
• Ability to work in a fast paced internet start-up environment.
• Experience in technical mentorship/coaching is highly desirable.
• Understanding of AI/ML algorithms is a plus.

Job Description

We are looking for Advance Java developers who want to help us design cutting edge scalable products to meet our rapidly growing business. We are building out a team and looking for multiple levels but you should have at least 4-6 years of programming experience.

Key Responsibilities

         Build high availability and extreme reliable high volume transactional systems.

         Deliver reliable solutions that handle massive data and high traffic.

         Complete ownership of problem-free execution of owned modules and solutions.

         Focus on code optimization, code quality, maintainability etc.

         Team Handling.

Skills required

         MS or BS/B.Tech / MCA in computer science.

         Hands-on experience in Core J2EE or Core Java (collection, multithreading).

         Proficiency in Struts 2.0 & Springs, Hibernate, JDBC, JSP, Servlets , JMS / Radius, Redis , Microservices , 

         Strong working knowledge of Databases – MySQL, OS - Linux.

         Experience and knowledge of open source tools & frameworks, broader cutting edge          technologies around server side development.

         Excellent data structure & algorithm and problem solving skills.

         Customer-focused, react well to changes, work with teams and able to multi-task.

         Must be a proven performer and team player that enjoy challenging assignments in a high-energy, fast growing and start-up workplace.

         Must be a self-starter who can work well with minimal guidance and in fluid environment.

Note: Must have worked on Payment Gateway Development.

Must be willing to work in a startup fast paced environment.

Joining : Immediate

• Understand the fundamentals of Software Engineering, such as Data Structures, Algorithms, Design Patterns
• Ability to write Java applications using Spring, Springboot or any other microservices frameworks
• Experience in the development of REST applications, in Java or Kotlin
• Capable of writing effective APIs
• Solid knowledge of JVM fundamentals such as classloading, memory management, garbage collection
• Demonstrated experience in platform API design and development
• Knowledge on microservice and event-driven architecture
• Experience in working with version control frameworks such as Git (preferable), SVN
•      Experience with NoSQL databases (MongoDB or Cassandra) & Relational Databases
• Solid understanding of TDD & Agile principles such as CI / CD, with a proven track record of implementing solutions centred around those concepts
• Excellent communication, collaboration, reporting, analytical and problem solving skills