Contract Java Developer Banking Jobs in Ontario (NOW HIRING)

Role Summary We're seeking a seasoned Senior Java Developer with 5+ years of experience to lead end-to-end technical design and delivery of missioncritical systems. You will own architecture decisions, drive engineering excellence, mentor senior engineers, and partner with product, security, and platform teams to build scalable, reliable, and secure distributed systems. Key Responsibilities: Architecture & Design Define and evolve system architecture for cloud-native, microservices/event-driven platforms (scalability, resilience, security, cost).

Create high-level and low-level designs, integration patterns, API contracts, and reference implementations. Lead design reviews; ensure alignment with domain-driven design (DDD), 12factor principles, and organization standards. Engineering Leadership Lead squads through full SDLC-from discovery and PoCs to production and SRE handoff.

Establish coding standards, code review practices, and secure-by-default patterns. Mentor and coach senior engineers; support career growth and succession of technical leaders. Hands-on Development Build core services using Java (17+), Spring Boot, REST/GraphQL, and message/event streaming.

Optimize for performance, concurrency, observability, and operational excellence (SLOs, error budgets). Drive quality with unit/integration/contract testing, test data strategy, and automated quality gates. Cloud & Platform Design for AWS/Azure/GCP, container orchestration (Kubernetes), service mesh, and CI/CD.

Implement infrastructure-as-code (IaC) patterns and secrets management. Partner with SRE/Platform teams on monitoring, alerting, logging, tracing, and cost governance. Data & Integration Architect integrations across SQL/NoSQL, caching (Redis), and event streams (Kafka/Pulsar).

Define data contracts, schema evolution strategies, and idempotent/eventual consistency patterns. Security & Compliance Embed AppSec best practices, OWASP controls, secure API/auth (OAuth2/OIDC), and zero trust patterns. Ensure compliance with regulatory and audit requirements where applicable.

Stakeholder Partnership Translate business needs into technical roadmaps and architecture runway. Communicate trade-offs and decisions to both technical and non-technical audiences. GenAI : Knowledge of MCP, A2A, Agentic Architecture Required Qualifications: 5+ years of progressive experience building enterprise systems, with 7+ years in Java and Spring at scale.

Proven delivery of cloud-native, microservices, and event-driven architectures. Strong expertise in: Java 11/17+, Spring Boot, Spring Cloud REST/GraphQL APIs, gRPC (nice-to-have) Kafka (or Pulsar), Kubernetes, Docker RDBMS (PostgreSQL/MySQL/Oracle) and NoSQL (MongoDB/Cassandra/DynamoDB) Caching (Redis), CI/CD (GitHub Actions/Azure DevOps/Jenkins), IaC (Terraform/ARM) Observability (OpenTelemetry, Prometheus/Grafana, ELK), feature flags/progressive delivery Solid grasp of concurrency, performance tuning, resiliency patterns (circuit breakers, retries, bulkheads), and fault-tolerance. Demonstrated leadership of architectural forums, design reviews, and mentorship.

Strong communication and stakeholder management skills. Nice-to-Have: Domain knowledge: Payments, banking, capital markets, insurance, e-commerce, supply chain, or telecom. Security: Threat modeling, shift-left security, SAST/DAST, secrets rotation, mTLS.

Data: CDC (Debezium), schema registry, exactly-once semantics, streaming ETL. Platform: Service mesh (Istio/Linkerd), API gateways (Kong/Apigee), Serverless (Lambda/Functions). Modern patterns: CQRS, event sourcing, Saga orchestration, hexagonal architecture.

Education: Bachelor's degree/University degree or equivalent experience This job description provides a high-level review of the types of work performed. Other job-related duties may be assigned as required. ------------------------------------------------------ Job Family Group: Technology ------------------------------------------------------ Job Family: Applications Development ------------------------------------------------------ Time Type: Full time ------------------------------------------------------ Primary Location Full Time Salary Range: $94,300.00 - $141,500.00 ------------------------------------------------------ Most Relevant Skills Please see the requirements listed above

------------------------------------------------------ Other Relevant Skills For complementary skills, please see above and/or contact the recruiter. ------------------------------------------------------ Automated Processing and AI We use automated processing, including artificial intelligence, for our legitimate business interests (or our reasonable and appropriate business purposes) to identify and align the candidate's skills and abilities with a specific job opening. Additionally, if you so choose, or consent, we can match your skills and abilities to other suitable roles at Citi.

Importantly, all our hiring processes and decisions, including determining your suitability for a role, are conducted, checked, and decided by individuals. Our automated processing and AI do not involve relying on automatic or autonomous decision-making. Please refer to any Jurisdictional Considerations, with specific provisions for your country (where relevant) for further details.

------------------------------------------------------ This job opening is for an existing job vacancy. ------------------------------------------------------ Citi is an equal opportunity employer, and qualified candidates will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law. If you are a person with a disability and need a reasonable accommodation to use our search tools and/or apply for a career opportunity review Accessibility at Citi.

View Citi's EEO Policy Statement and the Know Your Rights poster.