Full Stack Sofware Engineer

Simplex; Austin (TX); On-site; USD 220,000 - 280,000; Full time

Benefits offered by this job

Equity

Medical and dental benefits

401(k)

Weekly catered lunch

Job summary

Simplex is seeking a Full Stack Software Engineer in NYC to own features from conception to production. You will build intuitive experiences backed by robust APIs, data models, and infrastructure, collaborating with product partners, customers, and engineers.

The role emphasizes end-to-end ownership across customer-facing products and shared engineering foundations, with a core stack including TypeScript, React, Next.js, tRPC, Prisma, and PostgreSQL.

Qualifications

• Track record of owning substantial full-stack applications in production.
• Strong frontend fundamentals and modern state management.
• Strong backend and relational database skills, especially PostgreSQL.
• Practical understanding of distributed systems concepts such as concurrency, idempotency, retries, and partial failures.
• Experience troubleshooting production systems and improving reliability through observability.
• Product judgment and the ability to turn an ambiguous customer need into a focused, usable solution.
• The ability to independently move an open-ended project forward while communicating clearly with teammates.

Responsibilities

• Build and deliver full-stack features spanning React interfaces, backend services, APIs, and relational data models.
• Own projects through discovery, technical design, implementation, testing, release, and ongoing improvement.
• Improve checkout and payment reliability, accounting for concurrent activity, interrupted connections, retries, and transaction recovery.
• Develop reusable components, internal tools, and workflows that help other engineers build more effectively.
• Monitor and improve the systems you deliver, investigating performance issues across the browser, application, and database.
• Use logs, metrics, and tracing to diagnose production incidents and address their underlying causes.
• Incorporate AI coding tools into development while reviewing generated code and validating correctness.
• Contribute to architecture discussions, code reviews, and mentoring.

Skills

Frontend expertise

Backend development

Distributed systems

Observability

Product ownership

Communication

Tools

React

TypeScript

Next.js

tRPC

Prisma

PostgreSQL

AWS Aurora/RDS

Datadog

OpenTelemetry

Job description

This role is in-office M-F in the Flatiron District, NYC, NY.

Our client is a technology company building software that helps independent retailers manage and grow their businesses. Its platform connects essential retail operations, including checkout, payments, inventory, online sales, and back-office workflows, with AI-powered capabilities.

The engineering team works together in person in New York City, releases improvements frequently, and partners directly with business owners to understand how the product performs in day-to-day operations.

About the Role

Our client is seeking a Full Stack Software Engineer who combines strong technical fundamentals with thoughtful product judgment. You’ll own features from initial problem definition through production, building intuitive user experiences backed by reliable APIs, data models, and infrastructure.

This role offers substantial ownership across customer-facing products and shared engineering foundations. You’ll collaborate with product partners, customers, and fellow engineers to identify problems, evaluate tradeoffs, and deliver practical solutions.

The core technology stack includes TypeScript, React, Next.js, tRPC, Prisma, and PostgreSQL.

What You’ll Do

• Build and deliver full-stack features spanning React interfaces, backend services, APIs, and relational data models.

• Own projects through discovery, technical design, implementation, testing, release, and ongoing improvement.

• Improve checkout and payment reliability, accounting for concurrent activity, interrupted connections, retries, and transaction recovery.

• Develop reusable components, internal tools, and workflows that help other engineers build more effectively.

• Monitor and improve the systems you deliver, investigating performance issues across the browser, application, and database.

• Use logs, metrics, and tracing to diagnose production incidents and address their underlying causes.

• Incorporate AI coding tools into development while reviewing generated code and validating correctness.

• Contribute to architecture discussions, code reviews, and mentoring.

What You Bring

• A track record of owning substantial full-stack applications in production, with clear examples of your technical decisions and impact on users.

• Strong programming fundamentals and modern frontend expertise, including state management, accessibility, interaction design, and performance.

• Strong backend and relational database skills, particularly with PostgreSQL, including schema design, transactions, indexing, and query optimization.

• Practical understanding of distributed systems concepts such as concurrency, idempotency, retries, and partial failures.

• Experience troubleshooting production systems and improving reliability through effective observability.

• Product judgment and the ability to turn an ambiguous customer need into a focused, usable solution.

• The ability to independently move an open-ended project forward while communicating clearly with teammates.

Nice to Have

• Experience with payments, retail technology, point-of-sale systems, or software supporting multi-location businesses.

• Familiarity with card terminals, payment authorization and capture, or systems designed to remain resilient during connectivity issues.

• Experience with the core stack or infrastructure tools such as AWS Aurora/RDS, ElastiCache, Datadog, and OpenTelemetry.

• Experience creating shared architecture, development tools, or engineering practices adopted across teams.

• Experience building LLM-powered features or improving engineering workflows with AI coding tools.

Candidates do not need experience with every technology listed. Demonstrated engineering judgment, product ownership, and the ability to learn quickly are valued.

Compensation and Benefits

• Base salary of $220,000-$280,000, depending on experience, skills, and scope of responsibility.

• Meaningful equity.

• Fully company-covered medical and dental benefits.

• 401(k).

• Weekly catered lunch and dinner available each evening for employees who would like to eat with the team.

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