Senior Software Engineer (Full-Stack, JavaScript)

Senior-level candidates with 10+ years of experience building production-grade full-stack applications and leading significant systems are best suited for this role.

They should be highly skilled in JavaScript or TypeScript, React/Next.js, Node.js, REST and GraphQL APIs, databases, system architecture, cloud platforms, CI/CD, and infrastructure tools such as Terraform, with strong English communication skills.

The ideal person should be familiar with designing scalable architectures, building end-to-end products, leading technical discovery, collaborating with product and design, conducting code and design reviews, documenting decisions, mentoring engineers, and driving delivery from concept to deployment.

How would you structure a scalable Next.js application that includes both server-rendered pages and interactive client-side features?

I would separate server and client components intentionally, keep data fetching close to the server where possible, and define clear domain boundaries. I would also establish conventions for routing, loading and error states, caching, authentication, and shared UI to keep the application maintainable as it grows.

How would you design a Node.js and TypeScript backend for a product with multiple domains and evolving requirements?

I would organize the backend around domain modules with explicit service, repository, and API layers. TypeScript types, validation schemas, dependency inversion, structured logging, and consistent error handling would help preserve boundaries and support future changes.

What factors would you consider when choosing between REST and GraphQL for an API?

REST is often preferable for simple resource-oriented APIs, HTTP caching, and clear operational semantics, while GraphQL is useful when clients need flexible, aggregated data with varying shapes. I would evaluate client needs, authorization complexity, caching, observability, versioning, and operational cost before choosing.

How would you design a PostgreSQL data model for a high-traffic application with complex relationships?

I would begin with the business entities and access patterns, then choose normalized schemas where consistency is important and controlled denormalization where read performance requires it. I would use appropriate indexes, constraints, transactions, query analysis, and migrations, while planning for connection pooling and growth.

How would you improve the performance of a slow Next.js application?

I would measure first using browser profiling, application metrics, and server traces. Typical improvements include reducing client JavaScript, using server components and streaming, optimizing images and caching, eliminating unnecessary renders, improving database queries, and moving expensive work to asynchronous processes.

How would you implement authentication and authorization across a Next.js frontend and Node.js API?

I would centralize identity verification at the API boundary, use secure, short-lived sessions or tokens, and enforce authorization based on roles or resource ownership on the server. Cookies should be secure and HttpOnly where appropriate, while validation, CSRF protection, rate limiting, and audit logging should be considered.

What would a reliable CI/CD pipeline for a TypeScript full-stack application include?

The pipeline should run formatting, linting, type checks, unit tests, integration tests, and security checks before building immutable artifacts. Deployments should use environment-specific configuration, infrastructure managed through Terraform or similar tooling, automated migrations, health checks, observability, and a safe rollback strategy.

How would you design a cloud architecture for a scalable application on AWS or another major cloud provider?

I would separate compute, storage, networking, and data services according to the application’s requirements, using managed services where they reduce operational burden. The design should include least-privilege IAM, private networking for sensitive resources, autoscaling, backups, monitoring, disaster recovery, and cost controls.

How would you approach integrating an AI-enabled feature into a production application?

I would define the user outcome and evaluation criteria first, then isolate the AI integration behind a typed service boundary. I would address prompt or model versioning, latency, cost, privacy, retries, rate limits, fallbacks, output validation, monitoring, and human review for high-impact workflows.

How do you lead technical discovery and communicate architecture decisions to both engineers and non-technical stakeholders?

I would clarify goals, constraints, risks, and success metrics before comparing viable options. I would document the chosen design with diagrams and decision records, explain trade-offs in business terms, and validate the approach through prototypes, reviews, and incremental delivery.

Able is an ambitious, AI-native technology company building thoughtful products for a diverse portfolio of businesses. As a Senior Full-Stack Software Engineer, you’ll design scalable applications, APIs, architectures, and data models while guiding technical direction and collaborating with product and design. The stack includes TypeScript, JavaScript, React, Next.js, Node.js, REST, GraphQL, PostgreSQL/MySQL/DynamoDB, cloud platforms, CI/CD, and Terraform. This is a 100% remote role within Latin America, with compensation paid in USD (salary not disclosed), generous PTO, wellness benefits, AI-focused learning, and the opportunity to solve meaningful challenges with an ambitious team.