Junior Software Engineer

4 days ago

New York NY, New York County, NY; New York State, United States Kastel Group Full-time

Junior Software Engineer – Backend / Platform Systems

Location: New York, NY (Manhattan – Union Square)

Work Arrangement: Full-Time | Onsite 5 Days/Week

Salary: $125,000–$175,000 Base

Experience: 0–2 Years

Industry: Fintech | AI | Trading Technology | Marketplace

About the Opportunity

We are recruiting for a rapidly growing, highly profitable technology company developing advanced real-time pricing and trading systems.

Operating with the speed and sophistication of a high-frequency trading firm, the company has developed a proprietary platform that continuously processes market data, calculates pricing, manages transactions, and automates trading decisions.

The business has experienced exceptional growth, scaling from $0 to $80 million in just six months while remaining entirely bootstrapped and self-funded.

This is an exciting opportunity for an early-career Software Engineer to join a small, highly technical team and work directly on mission-critical production systems.

You'll gain hands-on experience with backend development, data infrastructure, cloud technologies, and production machine learning systems while making an immediate impact on a rapidly scaling business.

Key Responsibilities

  • Maintain and enhance backend systems supporting real-time pricing, bidding, and transaction processing.
  • Develop and manage data integrations, pipelines, and mapping workflows across multiple data sources.
  • Build internal tools and automation solutions to improve platform performance and operational efficiency.
  • Troubleshoot production issues and implement reliable, scalable solutions.
  • Integrate existing machine learning models into production applications and workflows.
  • Contribute to backend APIs, data infrastructure, and platform enhancements.
  • Collaborate directly with senior engineers on technical challenges and system improvements.
  • Participate in two-week development sprints and contribute across multiple engineering functions.

Required Qualifications

  • 0–2 years of professional software engineering experience, preferably focused on backend or systems development. Strong internship experience will be considered.
  • Bachelor's degree in Computer Science or a related STEM discipline.
  • Hands-on experience with Python and backend software development.
  • Experience building or maintaining backend systems, data integrations, pipelines, APIs, or internal engineering tools.
  • Exposure to platform infrastructure, production systems, or operations automation.
  • Ability to integrate existing machine learning models into production systems.
  • Strong analytical, problem-solving, and debugging skills.
  • Comfortable working in a fast-paced environment with a small engineering team.
  • Must be available to work onsite in Manhattan five days per week.
  • Must be authorized to work in the United States without current or future visa sponsorship.

Preferred Qualifications

  • Familiarity with cloud platforms such as AWS or Google Cloud Platform (GCP).
  • Experience with data processing, ETL pipelines, or distributed systems.
  • Exposure to machine learning infrastructure, model deployment, or production ML workflows.
  • Experience developing automation tools or supporting production applications.
  • Interest in financial technology, real-time systems, or algorithmic trading.
  • Experience working at a leading technology company or fast-moving startup.

Technology Stack

Python | AWS | GCP | Machine Learning | Data Pipelines | Data Infrastructure | Backend Systems | AI Development Tools

Why Join?

  • Competitive Compensation: $125,000–$175,000 base salary.
  • Exceptional Growth: Join a profitable, bootstrapped technology company experiencing extraordinary growth.
  • High-Impact Engineering: Work on financially critical, real-time systems used in live production.
  • Small Team, Significant Ownership: Collaborate closely with experienced engineers and contribute directly to core platform functionality.
  • Modern Technology: Gain practical experien