Backend Engineer – Node.js / PostgreSQL / AWS

Mappa; United States; Remote; USD 120,000 - 180,000; Full time

Job summary

Mappa, a US-based health-tech startup, is seeking a senior backend engineer to own and evolve our Node.js APIs and PostgreSQL data layer. You’ll start by collaborating with a senior backend engineer, then take ownership of backend deliverables, ensuring reliability and scalability across AWS deployments.

You’ll work with web and mobile engineers, optimize performance by removing N+1 queries, build partner integrations, maintain OpenAPI docs, and help shape the backend roadmap.

Qualifications

• 5+ years of backend experience with production Node.js APIs (Hapi/Express).
• Strong SQL and PostgreSQL skills including indexing and migrations.
• Hands-on AWS experience with deployments, CI/CD and containers.
• Proven ability to debug and maintain production systems you didn’t write.
• Experience building integrations with third-party APIs.

Responsibilities

• Maintain and improve the Node.js Hapi API and PostgreSQL database.
• Investigate production issues end to end: reproduce, trace logs and ship fixes.
• Build and support partner integrations such as wearable data ingestion and webhooks.
• Improve backend performance by removing slow endpoints and N+1 queries.
• Maintain AWS deployments, security basics, and monitoring across services.
• Keep API documentation and shared Postman collections up to date.

Skills

Backend development

Node.js

Express.js

PostgreSQL

AWS

Job description

About the company

We are innovators in fitness and health tech, leveraging cutting-edge computer vision to redefine movement assessment. Our dynamic team thrives in a collaborative environment, fostering growth and creativity while revolutionizing how bodies in motion are understood.

About the company

A US-based health-tech startup building movement-health assessments powered by computer vision. Its product is used through a React web dashboard and native iOS and Android apps. You'll join a small, senior, fully remote product team that works closely together.

The role

You'll start by working alongside a senior backend engineer, ramping up on the existing codebase through hands-on knowledge transfer. As you get up to speed, you'll gradually take ownership of the backend and become the de facto backend lead.

The system isn't overly complex. What matters here is solid engineering judgment, ownership, and working hand-in-hand with the web and mobile engineers. Your focus will be keeping the platform reliable and well maintained, and expanding it through new projects with the company's partners.

What you'll do

Maintain and improve the Node.js (Hapi) API and the PostgreSQL database, with growing ownership over time.

Investigate production issues end-to-end: reproduce the problem, trace it through logs and queries, ship the fix, and explain clearly what happened.

Expand the platform through partner projects and integrations, such as wearable data ingestion, subscription webhooks, deep-link tracking and SSO between apps.

Improve performance by removing N+1 queries and slow endpoints, and contribute to decisions on how the backend should evolve.

Maintain AWS deployments (ECS/Fargate, Lambda, API Gateway, RDS), security basics (IAM, secrets management) and monitoring (CloudWatch, Grafana).

Keep API documentation (OpenAPI/Swagger) and shared API collections (Postman or similar) up to date.

Work daily with the web and mobile engineers in Slack and GitHub, and explain technical trade-offs in plain English.

Must-haves

5+ years of backend experience, including production Node.js APIs (Hapi or Express).

Strong SQL and PostgreSQL skills: query plans, indexing, migrations.

Hands-on production experience with AWS, including deployments, CI/CD and containers.

Proven experience debugging and maintaining production systems in codebases you didn't write.

Experience building integrations with third-party APIs (webhooks, data ingestion, authentication).

Excellent spoken and written English. You can hold technical discussions with US teammates fluently and with ease.

Ownership mindset and readiness to grow into the backend lead role in a small team.

Full-time availability with substantial overlap with US business hours.

Nice to haves

Knex.js, Serverless Framework, Terraform, GitHub Actions.

Subscription billing integrations (e.g., RevenueCat, Stripe).

Health or wearable data integrations.

Event-driven patterns (SNS/SQS).

TypeScript.

Hiring process

Initial conversation with the hiring manager → technical interview with the engineering team → offer.

What we need you to tackle

We're looking for a senior backend engineer with 5+ years of experience shipping production Node.js APIs, strong PostgreSQL and SQL skills, and real-world AWS experience with deployments, CI/CD, and containers. You should be comfortable debugging systems you didn't build, integrating with third-party services, and making pragmatic engineering decisions in a small team. Clear communication, strong ownership, and the ability to collaborate closely with web and mobile engineers are essential, along with the judgment to grow into a backend lead role over time.

Non-negotiable hard skills

• Backend Development
• Express JS
• Node.js
• PostgreSQL
• AWS

Your day-to-day

• Maintain and improve the Node.js Hapi API and PostgreSQL database.
• Investigate production issues end to end, from reproduction through logs and queries to the final fix.
• Build and support partner integrations such as wearable data ingestion, subscription webhooks, deep-link tracking, and SSO between apps.
• Improve backend performance by identifying slow endpoints and removing N+1 queries.
• Maintain AWS deployments, security basics, and monitoring across ECS/Fargate, Lambda, API Gateway, and RDS.
• Keep API documentation and shared Postman collections accurate and up to date.

Nice to haves

• Identify and fix slow endpoints and N+1 patterns; apply caching, batching, and profiling to reduce tail latencies and costs.
• Instrument services with metrics, logs, and dashboards (CloudWatch, Grafana) and set actionable alerts to catch regressions early.
• Apply least-privilege IAM, secure secrets management, and safe API practices to protect data and integrations in a health-tech context.