Senior Backend Engineer - Node.js

Level: Senior Backend Engineer.

This role suits a professional with 5+ years of backend experience, strong Node.js and JavaScript expertise, and proficiency in frameworks, distributed systems, microservices, APIs, messaging and event streaming, NoSQL databases, caches, CI/CD, automated testing, debugging, and responsible AI-assisted development.

The candidate should be familiar with extending and maintaining existing services and modules, designing and integrating backend APIs, delivering complex features independently, resolving production issues, improving reliability and maintainability, and collaborating through code reviews in a remote team.

How would you design a scalable Node.js service for real-time translation requests?

I would separate request handling, stream processing, translation orchestration, and result delivery into independently scalable components. I would use asynchronous I/O, event-driven messaging, horizontal scaling, backpressure, timeouts, and clear observability to support low latency and reliable operation.

How do you manage asynchronous programming and error handling in Node.js?

I use promises and async/await with structured error handling, explicit timeouts, cancellation where appropriate, and centralized logging. I also ensure rejected promises are handled and distinguish between retryable, non-retryable, and user-facing errors.

How would you evolve an existing Node.js module without breaking its consumers?

I would first understand its public contract and usage patterns, then introduce backward-compatible changes with clear interfaces and regression tests. For breaking changes, I would use versioning, feature flags, migration paths, or an adapter layer.

How would you design an event-driven microservice workflow using a message broker?

I would define durable event contracts, idempotent consumers, correlation identifiers, retry policies, and dead-letter handling. The workflow should tolerate duplicate delivery, preserve required ordering, and expose metrics for lag, failures, and processing latency.

What strategies would you use to maintain consistency across distributed services?

I would avoid relying on distributed transactions when possible and use patterns such as transactional outbox, sagas, idempotency keys, and compensating actions. Data ownership and consistency expectations should be explicit for every service boundary.

How would you use a distributed cache in a Node.js backend?

I would cache data with carefully selected keys, TTLs, and invalidation rules while treating the cache as non-authoritative. I would also protect against cache stampedes, handle cache failures gracefully, and monitor hit rate, latency, and memory usage.

How would you choose and model data in a NoSQL database?

I would model around access patterns rather than normalization, selecting partition keys that distribute load evenly and support the required queries. I would account for item size, consistency requirements, indexes, pagination, retention, and schema evolution.

How would you test a Node.js service that integrates with messaging systems and external APIs?

I would use unit tests for business logic, integration tests with real or containerized dependencies, and contract tests for external interfaces. Tests should cover retries, duplicate messages, timeouts, partial failures, malformed data, and idempotent behavior.

How would you investigate a difficult production issue in a distributed backend?

I would correlate logs, metrics, traces, deployment changes, queue behavior, and dependency health using a request or correlation ID. I would first mitigate customer impact, then reproduce the issue, identify the root cause, add regression coverage, and document preventive improvements.

What would a reliable CI/CD pipeline for Node.js services include?

It should run formatting, linting, type or static checks where applicable, unit and integration tests, security scans, and build validation before deployment. Deployments should support reproducible artifacts, environment-specific configuration, health checks, gradual rollout, observability, and rollback.

Wordly is a fast-growing technology startup delivering real-time translation in 50+ languages to organizations worldwide. As a Senior Backend Engineer – Node.js, you’ll design and enhance backend services, APIs, integrations, and event-driven distributed systems while improving reliability, testing, and production performance. The stack includes Node.js, JavaScript, microservices, messaging and event streaming, NoSQL databases, distributed caches, CI/CD, and AI-assisted development tools, with Java/Kotlin experience a plus. This is a fully remote, full-time role open across the United States, Argentina, Brazil, and Canada; salary is not disclosed, making it an exciting opportunity to shape innovative global communication technology with a high-impact engineering team.