Senior Software Engineer (NX + NestJS)

Senior Software Engineer (NX + NestJS)-C2C/FTE- Downtown Toronto, Canada(Hybrid)
Full-time or Contract


Job Description:

Role Summary

A senior engineer to help deliver the AVA Modernization program, moving a legacy platform to a cloud-native architecture using NX monorepo, NestJS services, event-driven integration, and MongoDB/Snowflake data patterns. This is a hands-on role with architecture influence across BFF, microservices, ingestors, and workers.

Key Responsibilities

Build and scale services within a single NX monorepo using shared libraries and dependency-aware CI/CD.
Develop and evolve a NestJS BFF Gateway for multiple frontends, including JWT validation and OBO token exchange with Azure Entra ID.
Implement internal NestJS microservices with clear domain ownership and independent deployment.
Build ingestion services that consume external events, transform payloads, persist operational data, and publish internal domain events.
Develop async workers that process internal events for side effects (notifications, indexing, jobs) without tight service coupling.
Contribute to data-layer design:
MongoDB for operational/current-state reads
Snowflake for analytical/reporting workloads
Create and maintain shared libs/ contracts (DTOs, event payloads, auth utilities, API clients, validation rules).
Ensure strong testing, observability, performance, and production reliability standards.


Required Qualifications



5-10 years of backend engineering experience.
Strong hands-on expertise with NestJS (modules, DI, guards, interceptors, pipes, validation, Swagger/OpenAPI).
Practical experience with NX monorepos (shared libs, dependency graph, affected builds/tests).
Advanced TypeScript/Node.js skills and API/event contract design.
Experience with event-driven systems (Kafka or equivalent), including retries, idempotency, and schema/version evolution.
Experience building BFF/API orchestration layers across multiple upstream services.
Solid MongoDB experience for low-latency operational workloads.
Strong communication and collaboration skills in cross-functional delivery teams.


Preferred Qualifications



Ability to navigate and analyze C# and/or Java codebases at a working level — a significant portion of source-of-truth analysis will involve reading and interpreting existing legacy code in these languages to understand current business logic and inform how it should be reshaped to fit the new architecture.
Experience with Azure Entra ID and OAuth/OBO flows.
Exposure to GraphQL supergraph integrations from BFF layers.
Snowflake or similar analytical platform experience.
Experience migrating legacy services to containerized/cloud-native architectures.
Kubernetes/OpenShift delivery exposure.