Principal Software Engineer - Java

About NonStop io Technologies

NonStop io Technologies is a value-driven company with a strong focus on process-oriented software engineering. We specialize in Product Development and have a decade's worth of experience in building web and mobile applications across various domains. NonStop io Technologies follows core principles that guide its operations and believes in staying invested in a product's vision for the long term. We are a small but proud group of individuals who believe in the 'givers gain' philosophy and strive to provide value in order to seek value. We are committed to and specialize in building cutting-edge technology products and serving as trusted technology partners for startups and enterprises. We pride ourselves on fostering innovation, learning, and community engagement. Join us to work on impactful projects in a collaborative and vibrant environment.

Brief Description:

We're seeking an AI/ML Engineer to join our team. As AI/ML Engineer, you will be responsible for designing, developing, and implementing artificial intelligence (AI) and machine learning (ML) solutions to solve real-world business problems. You will work closely with engineering teams, including software engineers, domain experts, and product managers, to deploy and integrate Applied AI/ML solutions into the products that are being built at NonStop io. Your role will involve researching cutting-edge algorithms and data processing techniques, and implementing scalable solutions to drive innovation and improve the overall user experience.

Responsibilities

● Applied AI/ML engineering; Building engineering solutions on top of the AI/ML tooling available in the industry today. Eg: Engineering APIs around OpenAI

● AI/ML Model Development: Design, develop, and implement machine learning models and algorithms that address specific business challenges, such as natural language processing, computer vision, recommendation systems, anomaly detection, etc.

● Data Preprocessing and Feature Engineering: Cleanse, preprocess, and transform raw data into suitable formats for training and testing AI/ML models. Perform feature engineering to extract relevant features from the data

● Model Training and Evaluation: Train and validate AI/ML models using diverse datasets to achieve optimal performance. Employ appropriate evaluation metrics to assess model accuracy, precision, recall, and other relevant metrics

● Data Visualization: Create clear and insightful data visualizations to aid in understanding data patterns, model behaviour, and performance metrics

● Deployment and Integration: Collaborate with software engineers and DevOps teams to deploy AI/ML models into production environments and integrate them into various applications and systems

● Data Security and Privacy: Ensure compliance with data privacy regulations and implement security measures to protect sensitive information used in AI/ML processes

● Continuous Learning: Stay updated with the latest advancements in AI/ML research, tools, and technologies, and apply them to improve existing models and develop novel solutions

● Documentation: Maintain detailed documentation of the AI/ML development process, including code, models, algorithms, and methodologies for easy understanding and future reference.

Qualifications & Skills

● Bachelor's, Master's, or PhD in Computer Science, Data Science, Machine Learning, or a related field. Advanced degrees or certifications in AI/ML are a plus

● Proven experience as an AI/ML Engineer, Data Scientist, or related role, ideally with a strong portfolio of AI/ML projects

● Proficiency in programming languages commonly used for AI/ML. Preferably Python

● Familiarity with popular AI/ML libraries and frameworks, such as TensorFlow, PyTorch, scikit-learn, etc.

● Familiarity with popular AI/ML Models such as GPT3, GPT4, Llama2, BERT etc.

● Strong understanding of machine learning algorithms, statistics, and data structures

● Experience with data preprocessing, data wrangling, and feature engineering

● Knowledge of deep learning architectures, neural networks, and transfer learning

● Familiarity with cloud platforms and services (e.g., AWS, Azure, Google Cloud) for scalable AI/ML deployment

● Solid understanding of software engineering principles and best practices for writing maintainable and scalable code

● Excellent analytical and problem-solving skills, with the ability to think critically and propose innovative solutions

● Effective communication skills to collaborate with cross-functional teams and present complex technical concepts to non-technical stakeholders

Role

We are looking for a Full Stack Engineer who can own the entire technical stack, design systems that scale, and ship products fast. You will work across frontend, backend, and AI systems, making key architectural decisions while building a product used by real users.

This role offers high ownership, where engineers move ideas to production quickly and take responsibility for both technical decisions and product impact.

What would you do?

• Build and own the end-to-end platform using React, Node.js microservices, Python AI agents, and AWS.
• Design and implement scalable system architecture, including caching, databases, and state management between AI and UI.
• Develop AI-powered backend services and orchestrate LLM workflows using modern frameworks.
• Build highly interactive front-end experiences using modern React and real-time communication tools.
• Define and maintain engineering best practices, including CI/CD pipelines, monorepo structures, and development workflows.
• Collaborate closely with users and product teams to identify problems and ship impactful solutions.
• Continuously simplify systems by removing unnecessary complexity and keeping architecture clean.

Who should apply?

• Engineers with 4+ years of experience building and shipping production-grade products.
• Strong understanding of system design, architecture, and scalable backend systems.
• Hands-on experience with Python (FastAPI, async systems) and LLM-based applications.
• Proficiency in JavaScript / TypeScript with Node.js and modern backend frameworks.
• Experience building modern frontend applications using React (React 18+).
• Familiarity with databases such as Redis, PostgreSQL, or MongoDB, and designing scalable APIs.
• Engineers comfortable working in fast-paced environments with high ownership and minimal process overhead.

Technical Skills

• Backend: Node.js, Express, Python, FastAPI
• Frontend: React (React 18+), interactive UI development
• AI/LLM Systems: LLM orchestration, multi-model integrations
• Databases: Redis, PostgreSQL, MongoDB
• Infrastructure: AWS, CI/CD pipelines, microservices architecture
• Real-time Systems: Socket.IO, Server-Sent Events (SSE)

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.

Job Description

      The ideal candidate will possess expertise in Core Java (at least Java 8), Spring framework, JDBC, threading, database management, and cloud platforms such as Azure and GCP. The candidate should also have strong debugging skills, the ability to understand multi-service flow, experience with large data processing, and excellent problem-solving abilities.

JD:

1. Develop, and maintain Java applications using Core Java, Spring framework, JDBC, and threading concepts.
2. Strong understanding of the Spring framework and its various modules.
3. Experience with JDBC for database connectivity and manipulation
4. Utilize database management systems to store and retrieve data efficiently.
5. Proficiency in Core Java8 and thorough understanding of threading concepts and concurrent programming.
6. Experience in in working with relational and nosql databases.
7. Basic understanding of cloud platforms such as Azure and GCP and gain experience on DevOps practices is added advantage.
8. Knowledge of containerization technologies (e.g., Docker, Kubernetes)
9. Perform debugging and troubleshooting of applications using log analysis techniques.
10. Understand multi-service flow and integration between components.
11. Handle large-scale data processing tasks efficiently and effectively.
12. Hands on experience using Spark is an added advantage.
13. Good problem-solving and analytical abilities.
14. Collaborate with cross-functional teams to identify and solve complex technical problems.
15. Knowledge of Agile methodologies such as Scrum or Kanban
16. Stay updated with the latest technologies and industry trends to improve development processes continuously and methodologies.

• Implement best practices for the engineering team across code hygiene, overall architecture design, testing, and deployment activities
• Drive technical decisions for building data pipelines, data lakes, and analyst access.
• Act as a leader within the engineering team, providing support and mentorship for teammates across functions
• Bachelor’s Degree in Computer Science or equivalent job experience
• Experienced developer in large data environments
• Experience using Git productively in a team environment
• Experience with Docker
• Experience with Amazon Web Services
• Ability to sit with business or technical SMEs to listen, learn and propose technical solutions to business problems

·       Experience using and adapting to new technologies

·       Take and understand business requirements and goals

·       Work collaboratively with project managers and stakeholders to make sure that all aspects of the project are delivered as planned

·       Strong SQL skills with MySQL or PostgreSQL

• Experience with non-relational databases and their role in web architectures desired

 Knowledge and Experience:

• Good experience with Elixir and functional programming a plus

• Several years of python experience
• Excellent analytical and problem-solving skills
• Excellent organizational skills

Proven verbal and written cross-department and customer communication skills

• 3+ years of SDE work experience from Product based companies
• Experience in Java, Spring Boot, MySQL, Kafka, Hbase, AWS
  • Experience in Multi threading, distributed systems, Best practices of coding, scaling