Staff Software Engineer: External API & Booking Platform

Harnham; New York (NY); Hybrid; USD 190,000 - 240,000; Full time

Job summary

Harnham, a leading data and analytics firm in New York City, is seeking a Senior Software Engineer to lead design and development of a mission-critical external API used by partners and AI-driven booking channels.

The role focuses on transactional systems, inventory management, external integrations, API architecture, reliability, and platform scalability, with a strong emphasis on production ownership and observability.

Qualifications

• 8+ years of software engineering experience building backend or distributed systems.
• Experience designing transactional systems, public APIs, integration platforms, or reservation/commerce platforms.
• Strong understanding of relational databases, concurrency, consistency models, asynchronous workflows, and distributed systems failures.
• Experience evolving production data models and operating high-availability systems at scale.
• Hands-on experience with modern backend technologies such as Ruby on Rails, Node.js, PostgreSQL, REST APIs, and cloud infrastructure. (language-agnostic)
• Strong focus on system reliability, testing, observability, monitoring, and production ownership.

Responsibilities

• Design, build, and launch a versioned external API supporting pricing, availability, reservations, modifications, and cancellations.
• Develop resilient booking workflows that handle retries, idempotency, reconciliation, timeouts, duplicate requests, and partial failures.
• Own and evolve core booking domain models including inventory, pricing, scheduling, holds, carts, and bookings.
• Design scalable integration patterns for third-party systems, booking partners, POS, and property-management platforms.
• Build extensible platform capabilities that support multiple product categories without requiring separate booking systems.
• Establish observability, monitoring, testing, alerting, and operational best practices for critical booking services.
• Collaborate with engineering, product, and business stakeholders to translate complex requirements into durable platform solutions.

Skills

Backend systems

API design

Distributed systems

High availability

Tools

Ruby on Rails

Node.js

PostgreSQL

REST APIs

Cloud infrastructure

Job description

Harnham, a leading data and analytics firm in New York City, is seeking a Senior Software Engineer to lead design and development of a mission-critical external API used by partners and AI-driven booking channels.

The role focuses on transactional systems, inventory management, external integrations, API architecture, reliability, and platform scalability, with a strong emphasis on production ownership and observability.