Senior Software Engineer

Nue.io; Toronto; On-site; CAD 100,000 - 140,000; Full time

Job summary

Nue.io in Toronto, Ontario, is looking for a dedicated Senior Software Engineer to design and build scalable, multi-tenant SaaS systems. You’ll work with technologies such as Java, Spring Boot, and AWS to solve complex engineering challenges.

The ideal candidate will have experience in developing large-scale applications and a strong understanding of both relational and NoSQL databases. This role requires a proactive mindset and the ability to mentor junior engineers in a fast-paced environment.

Qualifications

• 5+ years of professional software development experience, designing and building large-scale, distributed backend systems.
• Deep understanding of relational databases including schema design, indexing, and performance optimization.
• Experience with event-driven architectures and streaming or messaging platforms.

Responsibilities

• Design, architect, and implement large-scale, multi-tenant SaaS applications.
• Own end-to-end feature delivery including scoping, design, implementation, testing, and operations.
• Collaborate closely with Product teams to translate business requirements into robust system designs.

Skills

Software development

Java/Spring Boot

Node.js/React

Distributed systems

SQL databases

Event-driven architectures

Cloud infrastructure

Agile methodologies

Education

Bachelor's degree in Computer Science or Software Engineering

Tools

AWS

Kafka

RabbitMQ

PostgreSQL

MySQL

Job description

What You'll Do

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.

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.

What You'll Bring

• 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.

Bonus Points (optional)

• 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.