Junior Software Engineer

Kastel Group; New York (NY); On-site; USD 125,000 - 175,000; Full time

Benefits offered by this job

401(k) matching

Healthcare contribution

Job summary

First Roles is seeking a Junior Software Engineer – Backend / Platform Systems in New York, NY. You will join a small, technically skilled team building real‑time pricing and trading platforms, with hands‑on backend, data infrastructure, and ML model integration responsibilities.

You will contribute to production systems, data pipelines, and tool development while learning cloud technologies in a fast‑growing fintech environment. Onsite five days per week in Manhattan.

Qualifications

• 0–2 years of professional software engineering experience, preferably focused on backend or systems development.
• 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.

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.

Skills

Python

Backend development

Data pipelines

Production systems

Education

Bachelor's degree in Computer Science

Tools

AWS

GCP

Job description

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 experience with machine learning integrations, AI‑assisted development tools, and cloud infrastructure.
• Career Development: Build valuable experience across backend engineering, data systems, automation, and production infrastructure.
• Benefits: 401(k) matching and a $600 monthly healthcare contribution.

Who Will Succeed in This Role?

We're looking for a curious, resourceful, and technically strong early‑career engineer who enjoys solving practical engineering problems.

The ideal candidate is equally comfortable developing new functionality, debugging existing systems, improving data workflows, and maintaining reliable production infrastructure.

This opportunity is particularly well suited to someone who wants broad engineering exposure, significant responsibility, and the chance to work on sophisticated systems early in their career.

If you're a Python‑focused backend engineer looking to accelerate your career with a high‑growth technology company, we'd love to hear from you.

No recruiters or third parties please.