Senior Software Engineer

nue.io•Toronto, ON

About The Position

We are seeking a highly motivated and experienced Senior Software Engineer to join our fast-growing team. You will design and build large-scale, multi-tenant SaaS systems that power Nue's core revenue workflows. You'll work across a powerful stack — Java/Spring Boot, Node.js/React, modern databases (SQL & NoSQL), event streaming platforms, and cloud infrastructure (AWS, Snowflake) — solving complex challenges in scalability, automation, and financial workflows.

Requirements

Bachelor's degree in Computer Science, Software Engineering, or a related field (or equivalent practical experience).
5+ years of professional software development experience, designing and building large-scale, distributed backend systems.
5+ years of experience with Java (or JVM languages) and building microservices on frameworks such as Spring Boot.
Deep understanding of relational databases (e.g., PostgreSQL, MySQL) including schema design, indexing, and performance optimization.
Experience with multi-tenant and/or sharded database architectures and strategies for scale and isolation.
Hands-on experience with event-driven architectures and streaming or messaging platforms (e.g., Kafka, Kinesis, RabbitMQ, Pub/Sub).
Solid understanding of data consistency models, idempotency, exactly-once / at-least-once processing, and eventual consistency patterns.
Experience with at least one major cloud provider (AWS, GCP, or Azure) and building cloud-native services (containers, serverless, managed data services).
Strong SQL skills and familiarity with database performance profiling and tuning.
Experience with concurrent programming and thread safety in production applications.
Experience with observability (metrics, logs, traces) and diagnosing performance and reliability issues in production.
Test-driven mindset, with hands-on experience writing and maintaining automated unit, integration, and end-to-end tests; familiarity with test automation frameworks such as Playwright or similar tools.
Strong portfolio or examples of past projects and code.
Strong communication and collaboration skills, with the ability to explain complex systems to both technical and non-technical stakeholders.
Enthusiasm for working in a fast-paced, startup-like environment and taking end-to-end ownership of critical systems.

Nice To Haves

Experience with finance, billing, subscriptions, payments, or revenue-lifecycle systems in a SaaS or financial-services context.
Experience with Snowflake or other modern data warehouses for reporting, analytics, and reconciliation use cases.
Familiarity with NoSQL or time-series databases and when to apply them alongside relational systems.
Experience with enterprise-scale systems and high-volume transactional workloads.
Understanding of compliance, security, and auditability concerns in financial systems (e.g., PCI considerations, data retention, audit trails).
Experience integrating with Salesforce or other CRM/ERP platforms.
Demonstrated ability to effectively use AI-assisted development tools (e.g., Claude Code, Codex, or similar) to accelerate development, improve code quality, debug complex issues, and explore system designs.
Strong attention to detail, ownership mindset, and comfort operating in ambiguous, evolving product domains.

Responsibilities

Design, architect, and implement large-scale, multi-tenant SaaS applications with a shared-nothing architecture based on the Spring Boot framework, leveraging microservices (API gateway, service registry, service monitoring), and event-driven patterns.
Own end-to-end feature delivery: scoping, design, implementation, testing, rollout, and operations.
Define and evolve domain models and data schemas to ensure accuracy, auditability, and long-term maintainability.
Build and maintain high-throughput, low-latency services that process large volumes of events with strong consistency and reliability guarantees.
Design and implement event-driven workflows using message queues and streaming platforms (e.g., Kafka, Kinesis, RabbitMQ, SNS/SQS, Webhooks).
Drive technical excellence and best engineering practices — design reviews, RFCs, continuous integration, code reviews, observability, CI/CD.
Provide architecture and technical guidance, and mentor other engineers in distributed systems design, database modeling, and scalability patterns.
Establish and maintain SLIs/SLOs (latency, throughput, accuracy, availability) for production services and continuously improve them.
Collaborate closely with Product and cross-functional teams to translate business requirements into robust, fault-tolerant system designs.
Deliver high-quality design and code using modern tools and agile methodologies including TDD, CI, refactoring, and code reviews.
Stay current with relevant technologies (event streaming, data infrastructure, security, AI-assisted development) and apply them pragmatically to Nue's SaaS platform.