Back End Developer

StarZen; Gurugram District; On-site; INR 1,400,000 - 2,500,000; Full time

Job summary

StarZen is seeking a Backend Developer to design, build, and maintain scalable server-side systems powering its digital products. You will work primarily with Python and FastAPI, while understanding .NET/ASP.NET Core to support existing applications and services.

You will design secure APIs, integrate multiple payment gateways, and develop robust database solutions, ensuring performance, reliability, and scalability across the platform.

Qualifications

• 5+ years of backend development experience.
• Proven experience with Python and FastAPI.
• Strong RESTful API development experience.
• Good knowledge of ASP.NET Core / .NET Core, C#, Web API, and Entity Framework.

Responsibilities

• Design, develop, and maintain scalable backend services and applications using Python and FastAPI.
• Build and maintain RESTful APIs for internal and external applications.
• Work with .NET / ASP.NET Core applications to understand, troubleshoot, and implement changes.
• Develop database-driven services and business logic with appropriate technologies.

Skills

Python

FastAPI

RESTful APIs

SQL

NoSQL

Pandas

NumPy

Payment gateways

Git

Docker

CI/CD

Azure

AWS

GCP

Entity Framework

Microservices

Security

Tools

SQL databases

NoSQL databases

PostgreSQL

MongoDB

Redis

DynamoDB

Docker

CI/CD

Azure

AWS

GCP

Entity Framework

Job description

The Backend Developer is responsible for designing, building, and maintaining scalable, secure, and high-performance server-side systems that power the organization's digital products. The role focuses on developing reliable backend services, APIs, business logic, database solutions, payment integrations, and third-party integrations across the platform.

The Backend Developer will primarily work with Python and FastAPI, while also having sufficient knowledge of .NET / ASP.NET Core to understand, manage, troubleshoot, and make required changes to existing .NET-based applications and services.

The role ensures that backend services are robust, well-architected, secure, maintainable, and capable of supporting business growth and increasing transaction volumes.

Accountability & Responsibilities of Role:-

1. Service Development & Ownership:-

• Design, develop, and maintain scalable backend services and applications using Python and FastAPI.
• Build and maintain RESTful APIs and backend services for internal and external applications.
• Work with existing .NET / ASP.NET Core applications and have sufficient knowledge to understand, manage, troubleshoot, and implement required changes.
• Develop database-driven services and business logic using appropriate backend technologies.
• Design scalable, secure, and maintainable server-side solutions aligned with business requirements.
• Design and optimize database schemas, queries, indexes, and stored procedures.
• Take ownership of backend services from development and testing through deployment, monitoring, and maintenance.

2. Database & Data Processing:-

• Work extensively with SQL databases such as SQL Server, PostgreSQL, MySQL, or similar technologies.
• Work with NoSQL databases such as MongoDB, Redis, DynamoDB, or similar technologies.
• Develop and optimize complex SQL queries and database operations.
• Handle database performance optimization, indexing, transactions, and data integrity.
• Use Pandas and NumPy for data processing, transformation, manipulation, and automation-related tasks.
• Design efficient data models based on application and business requirements.

3. API, Payment & Third-Party Integration:-

• Design and develop secure and reliable RESTful APIs.
• Integrate and maintain multiple payment gateways and payment-related services.
• Handle complete payment workflows including payment initiation, verification, transaction status, callbacks/webhooks, refunds, failed transactions, reconciliation, and idempotency.
• Integrate third-party APIs and external services with appropriate error handling and security practices.
• Ensure proper authentication, authorization, validation, and API security.
• Troubleshoot and resolve API, payment, and third-party integration issues.

4. Code Quality, Security & Collaboration:-

• Write clean, reusable, well-documented, and testable code following established coding standards.
• Follow OOP, SOLID principles, design patterns, and clean architecture wherever applicable.
• Participate in code reviews, sprint planning, technical design discussions, and architecture discussions.
• Collaborate with Frontend, QA, DevOps, Product, and other engineering teams.
• Maintain clear technical documentation for backend services, APIs, integrations, and databases.
• Follow security best practices for APIs, databases, authentication, authorization, and sensitive transaction data.

5. Performance, Reliability & Production Support:-

• Ensure backend applications and services meet required standards for performance, scalability, security, and reliability.
• Troubleshoot, debug, and resolve production issues across application, API, database, payment, and integration layers.
• Identify and resolve performance bottlenecks and recurring production issues.
• Contribute to root-cause analysis and incident resolution.
• Support application monitoring, logging, error handling, and production maintenance.
• Identify technical debt and recommend improvements to improve system stability and maintainability.
• Use Python for scripting, automation, data processing, and integration-related tasks where required.
• Exposure to AI/ML concepts, tools, or APIs is a plus.
• Stay updated with relevant developments in Python, FastAPI, .NET, databases, and backend technologies.
• Recommend and adopt tools, libraries, and architectural improvements that improve development efficiency, system reliability, and scalability.
• Contribute to shared libraries, coding standards, reusable components, and internal technical documentation.

Position Requirements:-

• 5+ years of professional experience in backend development.
• Strong hands-on experience with Python and FastAPI.
• Strong experience in RESTful API development and backend services.
• Good working knowledge of ASP.NET Core / .NET Core, C#, Web API, and Entity Framework, with the ability to understand, manage, troubleshoot, and make required changes in existing .NET-based applications and services.
• Strong understanding of Object-Oriented Programming, SOLID principles, design patterns, and clean architecture.
• Hands-on experience with SQL databases such as SQL Server, PostgreSQL, MySQL, or similar.
• Hands-on experience with NoSQL databases such as MongoDB, Redis, DynamoDB, or similar.
• Strong knowledge of SQL queries, database design, indexing, transactions, stored procedures, and query optimization.
• Hands-on experience with Pandas and NumPy for data processing and manipulation.
• Proven experience integrating and working with multiple payment gateways and payment APIs.
• Experience with payment workflows, webhooks, callbacks, refunds, transaction verification, reconciliation, and failure handling.
• Experience integrating third-party APIs and external services.
• Strong understanding of API security, authentication, authorization, JWT/OAuth, and input validation.
• Experience with Git/version control.
• Knowledge of Docker, CI/CD, and cloud platforms such as Azure, AWS, or GCP is preferred.
• Exposure to microservices, caching, message queues, background jobs, or asynchronous processing is a plus.
• Exposure to AI/ML tools, APIs, or concepts is a strong plus.
• Strong backend development and problem-solving skills.
• Ability to build and maintain scalable, secure, and reliable backend systems.
• Strong expertise in Python and FastAPI with practical production experience.
• Ability to work effectively with SQL and NoSQL databases.
• Practical experience with multiple payment gateway integrations and payment workflows.
• Ability to understand and manage existing .NET / ASP.NET Core-based systems.
• Strong debugging and troubleshooting capabilities across application, API, database, and integration layers.
• Ability to identify performance bottlenecks and improve application reliability and response times.
• Strong understanding of clean, maintainable, and testable code.
• Effective collaboration with Frontend, QA, DevOps, and Product teams.
• Ability to take ownership of backend services from development through deployment and production support.