Senior Software Engineer, Backend – Platform & API Development

Atrium Staffing LLC

New York (NY)

On-site

USD 190,000 - 210,000

Full time

3 days ago

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Benefits offered by this job

Equity

Career growth

Technical ownership

Collaborative environment

Cutting-edge tech

Job summary

Atrium Staffing LLC is seeking a Senior Software Engineer, Backend – Platform & API Development to design, develop, and scale our core platform and external API infrastructure from end to end. This hands-on role requires ownership of backend architecture and the ability to deliver reliable, scalable solutions in a fast-growing environment.

Responsibilities include building external APIs, integrating with third-party services, and driving transactional workflows for bookings, payments, and

Qualifications

6+ years of professional software engineering experience, primarily backend or platform development.
Experience independently designing, developing, and deploying complex backend systems.
Strong experience building external-facing APIs and integrating with third-party services.
Experience with transactional systems involving bookings, payments, inventory, or orders.
Strong understanding of relational databases, data modeling, and backend architecture.
Solid CS fundamentals and problem-solving abilities.
Experience in established engineering organizations with standards and best practices.
Ability to own technical projects and make architectural decisions.
Strong communication and collaboration skills.
Willingness to remain hands-on with software development.
Ability to work onsite in New York City four days per week.

Responsibilities

Design, develop, and maintain scalable backend systems for the platform and API.
Build and maintain external-facing APIs and third-party integrations.
Develop reliable transactional workflows involving bookings, payments, inventory, and reservations.
Own backend architecture, API design, and technical implementation decisions.
Design relational database models with high consistency and scalability.
Collaborate with senior engineers on foundational architecture and long-term strategy.
Develop reusable patterns to support future platform integrations.
Partner with product managers to translate requirements into technical solutions.
Write, test, deploy, and maintain high-quality production code.
Identify opportunities to improve performance, reliability, and efficiency.

Skills

Backend development

APIs

System design

Relational databases

Team collaboration

Problem solving

Hands-on coding

Technical ownership

Communication

Onsite work

Education

Bachelor's degree in CS/SE

Tools

Ruby on Rails

Node.js

PostgreSQL

AWS

Redis

Kafka

Datadog

OpenSearch

Job description

Client Overview:

Our client is a rapidly growing, profitable technology company operating a digital marketplace that connects consumers and businesses through innovative technology solutions. The organization is continuing to expand its platform, product offerings, and engineering team to support increasing demand and is seeking a Senior Software Engineer, Backend – Platform & API Development.

With a strong focus on technical excellence, collaboration, and innovation, the company offers engineers the opportunity to take ownership of meaningful projects, contribute to architectural decisions, and build scalable systems that support long-term growth.

Salary/Hourly Rate:

$190k - $210k

Position Overview:

A Senior Software Engineer, Backend – Platform & API Development will help to design, develop, and scale its core platform and external API infrastructure.

This individual will play a critical role in building reliable backend systems, developing third-party integrations, and supporting complex transactional workflows involving bookings, payments, inventory, and reservations.

The ideal candidate has strong computer science fundamentals, experience developing scalable production systems, and the ability to independently own technical projects from initial design through deployment.

This is a hands-on individual contributor opportunity offering significant technical ownership, collaboration with experienced engineering leadership, and potential advancement into a Staff Engineer position.

Responsibilities of the Senior Software Engineer, Backend – Platform & API Development:

Design, develop, and maintain scalable backend systems supporting a high-growth digital platform.
Build and maintain external-facing APIs and integrations with third-party platforms.
Develop reliable transactional workflows involving reservations, bookings, inventory, and payments.
Take ownership of backend architecture, API design, and technical implementation decisions.
Design relational database models with an emphasis on consistency, scalability, and data integrity.
Collaborate with senior engineers on foundational architecture and long-term technical strategy.
Develop reusable engineering patterns to support future platform integrations.
Partner with product managers and cross-functional stakeholders to translate business requirements into technical solutions.
Write, test, deploy, and maintain high-quality production code.
Identify opportunities to improve system performance, reliability, and engineering efficiency.

Required Experience/Skills for the Senior Software Engineer, Backend – Platform & API Development:

6+ years of professional software engineering experience, primarily focused on backend or platform development.
Proven experience independently designing, developing, and deploying complex backend systems.
Strong experience building external-facing APIs and integrating with third-party services.
Experience developing transactional systems involving payments, orders, bookings, reservations, inventory, or similar workflows.
Strong understanding of relational databases, data modeling, data consistency, and backend architecture.
Solid computer science fundamentals and strong technical problem-solving abilities.
Experience working within an established engineering organization with strong technical standards and best practices.
Demonstrated ability to take ownership of technical projects and make sound architectural decisions.
Strong communication and collaboration skills.
Ability to quickly learn new technologies and adapt to evolving technical requirements.
Interest in remaining hands-on with software development.
Ability to work onsite in New York City four days per week.

Preferred Experience/Skills for the Senior Software Engineer, Backend – Platform & API Development:

Experience with Ruby on Rails, Node.js, PostgreSQL, and AWS.
Familiarity with Redis, Kafka, Datadog, or OpenSearch.
Experience developing high-volume transactional platforms, marketplaces, payment systems, or booking applications.
Experience building scalable API infrastructure and complex third-party integrations.
Background at a well-established technology company or high-performing product engineering organization.
Experience working in a rapidly growing startup environment.
Familiarity with AI-assisted development tools, including LLM coding agents.
Experience owning technical initiatives from initial architecture through production deployment.

Education Requirements:

Bachelor's degree in Computer Science, Software Engineering, or a related technical field preferred. Equivalent professional experience and demonstrated technical expertise will also be considered.

Benefits: