Principal Back-End Engineer

Toptal

Senior Back-End Engineer at Toptal building an AI-powered career services platform. Collaborating on Rails API, event-driven systems, and third-party integrations.

Posted 4/28/2026full-timeRemote • 🇨🇦 CanadaLeadWebsite

Tech Stack

Tools & technologies

CloudPostgresRedisRubyRuby on Rails

About the role

Key responsibilities & impact

Build, maintain, and own Rails API capabilities across multiple business domain packs.
Design and implement background job workflows with Sidekiq for async and parallel processing.
Integrate and optimize LLM-based features for resume analysis, writing, and generation.
Build and maintain event-driven systems using pub/sub patterns for cross-domain communication.
Design PostgreSQL schemas and data models with strong attention to data integrity.
Integrate third-party services, including payment processors, email providers, and cloud services.
Maintain and evolve a modular monolith architecture with explicit package and domain boundaries.
Collaborate closely with front-end and infrastructure teams on API contracts, deployment workflows, and production reliability.
Use AI development tools daily to increase delivery speed, improve code quality, and explore implementation options.

Requirements

What you’ll need

Senior or Principal-level back-end engineering experience, with a strong delivery track record.
8+ years of professional Ruby on Rails development.
Strong PostgreSQL skills, including schema design, migrations, relational modeling, and query optimization.
Experience with async/background processing systems such as Sidekiq or equivalent.
Redis proficiency, especially caching and session management.
Strong REST API design and implementation experience at production scale.
Experience integrating external APIs such as payment processors, email providers, cloud storage, or support platforms.
Comfortable working in modular monoliths or similarly structured codebases with clear domain boundaries.
Ability to reason about scalability, performance, observability, and data integrity.
Strong technical ownership, including architectural judgment and accountability for implementation decisions.
Fast, independent, methodical working style with strong written and verbal English communication.
Daily use of AI development tools to accelerate development and improve engineering quality.

Benefits

Comp & perks

Competitive salary
Flexible working arrangements

ATS Keywords

✓ Tailor your resume

Applicant Tracking System Keywords

Tip: use these terms in your resume and cover letter to boost ATS matches.

Hard Skills & Tools

Ruby on RailsPostgreSQLSidekiqRedisREST APIasync processingbackground job workflowsdata integrityschema designquery optimization

Soft Skills

technical ownershiparchitectural judgmentaccountabilityindependent workingmethodical workingwritten communicationverbal communication