Senior Software Engineer II

Extend; New York (NY); On-site; USD 171,000 - 198,000; Full time

Benefits offered by this job

Medical and dental benefits

Competitive salary

Flexible paid time off

Stock options

401(k) with Financial Guidance

Job summary

Extend is looking for a Senior Software Engineer II to join the Fulfillments team in New York. This role offers the chance to create software that enhances the post-purchase experience for major merchants.

The ideal candidate should have over 8 years of full-stack experience, expertise in TypeScript, Node.js, and React, and a strong understanding of AWS infrastructure and AI features.

Extend provides a competitive salary, medical benefits, flexible PTO, and stock options in a fast-growing startup.

Qualifications

• 8+ years of full-stack experience.
• Proven track record building distributed systems on AWS with serverless experience.
• Experience shipping AI/LLM features to production.
• Understanding of API design, versioning, and idempotency.

Responsibilities

• Tackle ambiguous, cross-system problems in fulfillment.
• Own large features end to end, from design to deployment.
• Deliver scalable, event-driven, AI-native applications.
• Collaborate with platform teams to improve system architecture.

Skills

Full-stack development

AWS

API design

TypeScript

Node.js

React

AI/LLM features

Data modeling

Strong communication skills

Mentoring

Job description

About Extend:

Extend is revolutionizing the post-purchase experience for retailers and their customers by providing merchants with AI-driven solutions that enhance customer satisfaction and drive revenue growth. Our comprehensive platform offers automated customer service handling, seamless returns/exchange management, end-to-end automated fulfillment, and product protection and shipping protection alongside Extend's best-in-class fraud detection. By integrating leading-edge technology with exceptional customer service, Extend empowers businesses to build trust and loyalty among consumers while reducing costs and increasing profits.

Today, Extend works with more than 1,000 leading merchant partners across industries, including fashion/apparel, cosmetics, furniture, jewelry, consumer electronics, auto parts, sports and fitness, and much more. Extend is backed by some of the most prominent technology investors in the industry, and our headquarters is in downtown San Francisco.

About The Role:

We are looking for an exceptional Senior Software Engineer II to join the Extend Fulfillments team, a core pillar driving our company's growth and customer satisfaction. This role offers a unique opportunity to build impactful software used by some of the largest ECommerce and Brick and Mortar merchants in the industry, and directly influencing how our merchants make their customers whole.

You’ll partner closely with cross-functional teams in product, design, operations, delivery and the broader engineering organization - contributing significantly to a culture of innovation, continuous improvement, and excellence.

What You'll Do:

• Tackle ambiguous, cross-system problems spanning all aspects of fulfillment and servicing — refunds, replacements, reverse logistics, and more
• Own large features end to end, from design through deployment, release, and monitoring
• Deliver scalable, event-driven, AI-native applications that elevate the customer experience
• Collaborate with platform teams to enhance overall system architecture
• Own the design, implementation, quality and safety of AI/agentic features in production systems
• Mentor other engineers across levels through code review, pairing, design collaboration and coaching
• Drive adoption of tooling and practices, including AI developer tooling, and codify the habits that make them effective
• Advocate for the proactive investments — refactors, observability, upgrades, technology adoption - that enable continuous improvement
• Communicate fluently across product, design, solutions, and ops to align outcomes with business goals

What We're Looking For:

• 8+ years of full-stack experience
• Proven track record building distributed, highly available systems on AWS, with hands-on serverless experience
• Demonstrated experience shipping AI/LLM features to production
• Strong instincts for API design, versioning, idempotency, and backwards compatibility — especially where events drive money movement or fulfillment
• A track record of owning large, ambiguous, cross-system initiatives end to end
• Proven ability to influence beyond your team — aligning groups, distilling complex ideas for leadership, and pushing back with data
• A pattern of mentoring across levels and driving team-wide improvements that outlast any single project
• Strong data modeling and context engineering skills that ensure application quality and sound agentic decisioning
• Fluency with advanced AI developer tooling, a track record of using it to ship more, and a habit of bringing teammates along
• Exceptional communication across product, business stakeholders, designers, support, and engineers
• Expert in TypeScript, Node.js, and React

Estimated Pay Range: $171,000 - $198,000 per year salaried*

* The target base salary range for this position is listed above. Individual salaries are determined based on a number of factors including, but not limited to, job-related knowledge, skills and experience.

Life at Extend:

• Working with a great team from diverse backgrounds in a collaborative and supportive environment.
• Competitive salary based on experience, with full medical and dental & vision benefits.
• Stock in an early-stage startup growing quickly.
• Generous, flexible paid time off policy.
• 401(k) with Financial Guidance from Morgan Stanley.

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