Mississauga, On Senior java developer (contract) Jobs – 69 Openings This Week

Lead Java Platform Engineer (Payments Processing) - Senior Vice President
Citi —Mississauga, ON
- $145,100–$217,700 a year
- Full-time
- Oracle
- DevOps
- Java
1d
Senior Java Developer (onsite - Cambridge, ON)
VectorVue —Toronto, ON
- $100,000–$150,000 a year
- Full-time
- Java
- Databases
- SQL
Quick apply
20h
Senior Golang & Java Developer
GFT Technologies SE —Toronto, ON
- $75–$95 an hour
- Part-time
- Azure
- Java
- SQL
Senior Full Stack Developer
Aarorn Technologies Inc. —Toronto, ON
- $45–$47 an hour
- Azure
- DevOps
- Java
Quick apply
19h
Senior IT Recruitment Consultant - VMS
Robertson & Company —Toronto, ON
- $65,000–$75,000 a year
- Full-time
- Hybrid work
- Java
- SQL
- Accounting
- Dental care
- Vision care
Quick apply
15h
Senior Data Analytics Engineer
BMO Financial Group —Toronto, ON
- $67,200–$124,200 a year
- Full-time
- Java
- SQL
- AWS
- Tuition reimbursement
- Life insurance
RQ10028 - Sr. Software Developer - Front End
Source Code —Toronto, ON
- Full-time
- Azure
- Oracle
- Java
Quick apply
RQ09842 - Sr. Software Developer
Source Code —Toronto, ON
- Full-time
- Azure
- Oracle
- DevOps
Quick apply
RQ10070 - 3 x Sr. Software Developer - Full Stack
Source Code —Toronto, ON
- Full-time
- Azure
- Oracle
- DevOps
Quick apply
RQ10248 - Sr. Software Developer
Source Code —Toronto, ON
- Full-time
- Oracle
- Java
- SQL
Quick apply
RQ10808 - 3 x Sr. Software Developer
Source Code —Toronto, ON
- Full-time
- Oracle
- Java
- Databases
Quick apply
RQ09943 - Sr. Software Developer - Full Stack
Source Code —Toronto, ON
- Full-time
- Azure
- Oracle
- DevOps
Quick apply
RQ10542 - Sr. Software Developer
Source Code —Toronto, ON
- Full-time
- Azure
- Oracle
- Java
Quick apply
RQ09380 - Sr. Software Developer - Full Stack
Source Code —Toronto, ON
- Full-time
- Hybrid work
- Azure
- Oracle
- DevOps
Quick apply
RQ09528/ RQ09623 - Sr. Software Developer - Full Stack
Source Code —Toronto, ON
- Full-time
- Oracle
- DevOps
- Java
Quick apply
RQ09848 - Sr. Siebel Developer - CRM
Source Code —Toronto, ON
- Full-time
- Oracle
- Java
- JavaScript
Quick apply
RQ11125 - Sr. DevOPS/Cloud Engineer
Source Code —Toronto, ON
- $72.30–$108.48 an hour
- Full-time
- Azure
- Oracle
- DevOps
Quick apply
RQ10903 - Sr. Software Developer
Source Code —Toronto, ON
- Azure
- Oracle
- Java
Quick apply
RQ09714 - Sr. Software Developer - Full Stack
Source Code —Toronto, ON
- Full-time
- Hybrid work
- Azure
- Java
- APIs
Quick apply
RQ09885 - Sr. Software Developer - API
Source Code —Toronto, ON
- Weekends as needed
- Azure
- Oracle
- Java
Quick apply

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Lead Java Platform Engineer (Payments Processing) - Senior Vice President

Citi -
Mississauga, ON

Apply Now

Job details

Full-time
$145,100–$217,700 a year
1 day ago

Qualifications

Spring Boot
CI/CD
SAFe
Oracle
Gradle
Law
React
Kubernetes
DevOps
System architecture
Disaster recovery
Microsoft SQL Server
NoSQL
MongoDB
.NET
Java
Master's degree
Databases
Microservices
SQL
AWS
C++
Docker
Bachelor's
REST
COBOL
GitHub
APIs
Agile
Kafka
Maven
AI
Jenkins
Communication skills
High availability
Spring MVC

Full job description

About the Role

We are seeking an experienced, hands-on Senior Java Developer to contribute to the development of our engineering frameworks, with a strong focus on microservice architecture. This senior engineering leadership role merges hands-on technical contribution with organizational accountability. The ideal candidate will remain deeply involved in the code and architecture while simultaneously owning the platform strategy, defining engineering standards, and guiding a scrum team in developing core functionalities within the payments lifecycle.

Key Responsibilities

1. Hands-On Technical Contribution & System Design

Actively code in Java, developing reusable frameworks while performing system design, architecture reviews, and code reviews for the core cheque payment platform.
Contribute to the design of distributed, fault-tolerant, real-time systems for high-volume, low-latency transaction processing.
Write, review, and refactor production-grade code in Java setting a high technical standard for the team.
Independently design event-driven, microservices-based architectures utilizing REST APIs, Java and React.
Apply hands-on experience with Kafka, including message schema design, topic partitioning, consumer group strategies, and fault-tolerant processing.
Design and govern data architecture across Oracle (SQL) and MongoDB (NoSQL), covering schema design, indexing strategies, query optimization, and data consistency patterns.
Champion continuous development, feature flags, and progressive delivery, contributing to the design and optimization of CI/CD pipelines.
Produce and review Architecture Decision Records (ADRs) and technical design documents for key platform components.

2. Engineering Excellence & Quality

Maintain and enforce engineering standards within the scrum team, including Test-Driven Development (TDD), reusable framework development, CI/CD, secure coding, and observability.
Conduct code reviews for critical platform components, providing detailed technical feedback to enhance team quality and capacity, ensuring the development of scalable and reusable services.
Drive the adoption of AI-powered quality practices, including leveraging tools like GitHub Copilot for coding, utilizing LLMs (Gemini experience preferred) to improve payment processing quality, and implementing automated test script generation and vulnerability remediation.
Lead performance engineering initiatives, including profiling JVM-based applications Java identifying performance hotspots, and optimizing critical settlement processing paths.
Own the security and compliance posture of the cheque payment platform by participating in threat modeling, vulnerability assessments, and secure design reviews.
Ensure all engineering delivery aligns with Citi Engineering Excellence Standards, including CI/CD, DevOps, cloud-native practices, and modern ways of working.

3. Platform Strategy & Domain Ownership

Define and own the engineering roadmap for modernizing the cheque payment platform, migrating global components from monolithic mainframe and legacy applications to a reusable microservices architecture.
Develop strong domain knowledge in the payment lifecycle, settlement, and cheque image processing to inform sound engineering decisions.
Own the platform's SLA commitments, driving architectural decisions to meet availability, throughput, and latency targets.
Develop cross-platform integration by governing API contracts, data flows, and system dependencies across the Payments, Settlements, DDA, and Data Lake ecosystems.
Drive capacity planning and investment prioritization, making informed decisions on platform scaling, technology refresh, and resource allocation.
Partner with Operations, Risk, Compliance, and Business teams to ensure the platform meets all regulatory requirements and business needs.

4. Leadership & Stakeholder Engagement

Act as the primary engineering point of contact for the core Cheque Processing pillar, engaging with senior business, technology, and operations stakeholders.
Clearly communicate platform health, delivery progress, engineering strategy, and risks to senior leadership.
Partner with Product, Operations, Risk, Finance, and Compliance teams to align engineering priorities with business and regulatory needs.
Demonstrate the ability to pivot direction to meet timelines and delivery commitments with tactical solutions, while maintaining a clear vision for strategic platform development.

Required Skills and Qualifications

1. Core Programming & System Architecture

Java: 10+ years of Extensive hands-on experience in high-throughput, production-grade Java engineering, including JVM performance tuning.
API Development: Hands-on experience building RESTful APIs with frameworks such as Spring MVC or Spring Boot.
Microservices Architecture: Proven experience designing microservices ecosystems, including service decomposition, API design, inter-service communication, and cloud engineering.
Event-Driven & Messaging Systems: Deep, hands-on expertise in Kafka, including topic design, partitioning, consumer groups, exactly-once semantics, and high-throughput stream processing.
High-Performance Computing: Hands-on experience with profiling and optimization, including JVM tuning, garbage collection (GC) optimization, thread management, and memory profiling.
High Availability & Fault Tolerance: Practical experience designing resilience patterns such as circuit breakers, bulkheads, failover, and disaster recovery.
Databases: Hands-on expertise in Oracle (SQL) and Microsoft SQL for schema design, query optimization, and indexing, as well as MongoDB (NoSQL) for document modeling, aggregation pipelines, sharding, and replica sets.

2. Cloud & DevOps

Cloud-Native Engineering: Hands-on experience with OpenShift/AWS, Kubernetes, and Docker for container orchestration, autoscaling, and cloud-native deployment.
CI/CD & DevOps: Experience designing and owning CI/CD pipelines aligned with enterprise-level Engineering Excellence Standards. Experience with tools like Jenkins and Gradle/Maven.
Observability: Hands-on experience with distributed tracing, intelligent alerting, and AI-driven observability using tools like Grafana.
Secure Engineering: Practical experience with threat modeling, vulnerability assessments, and secure design reviews.
Agile at Scale: Experience with Agile/SAFe delivery at the program level, including PI planning, cross-team dependency management, and delivery governance.

Good-to-Have Skills

ML Integration: Hands-on experience with real-time ML model serving, including feature stores, online inference, and model monitoring.
AI Frameworks: Familiarity with Retrieval-Augmented Generation (RAG) patterns, vector databases (e.g., Pinecone, Weaviate), or agentic AI frameworks (e.g., LangChain, AutoGen).
Resilience Testing: Experience with chaos engineering and resilience testing, including fault injection and production readiness reviews.
Financial Systems: Knowledge of reconciliation and exception handling patterns in settlement workflows.
LLM Experience: Familiarity with prompt engineering and LLM fine-tuning in a regulated enterprise context.
Legacy Modernization: Experience with large-scale transformation projects, including migrating mainframe components (COBOL, Assembler) and legacy systems (C++, .NET) to a microservices architecture.
Strategy: Experience with technology investment governance and engineering budget management.

What We Are Looking For

A hands-on leader who actively contributes to code, frameworks, reviews, and technical problem-solving.
A strategic thinker who is equally comfortable at the code/architecture level and the platform strategy/stakeholder management level.
A pragmatic innovator who identifies practical, high-value opportunities to apply AI/ML without losing focus on engineering fundamentals.
An accountable owner with a strong sense of ownership for platform quality, reliability, and delivery.
A mentor committed to developing engineers and managers, building technical capability and leadership depth across the team.
An effective communicator able to translate technical complexity into clear, concise updates for business and senior leadership.

Why Join Us

Lead engineering for a central global payment platform while remaining deeply technical.
Drive AI and engineering transformation on a high-visibility modernization initiative with significant business impact.
Work at the intersection of high-throughput financial systems and modern AI capabilities.
Build and mentor a strong engineering team with access to state-of-the-art tools, platforms, and talent.
Be part of an engineering culture that values technical depth at every level of seniority.

Education:

Bachelor’s degree/University degree or equivalent experience
Master’s degree preferred

Job Family Group:

Technology

Job Family:

Applications Development

Time Type:

Full time

Primary Location Full Time Salary Range:

$145,100.00 - $217,700.00

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.

Apply Now

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About the Role

Key Responsibilities

1. Hands-On Technical Contribution & System Design

Actively code in Java, developing reusable frameworks while performing system design, architecture reviews, and code reviews for the core cheque payment platform.

Contribute to the design of distributed, fault-tolerant, real-time systems for high-volume, low-latency transaction processing.

Write, review, and refactor production-grade code in Java setting a high technical standard for the team.

Independently design event-driven, microservices-based architectures utilizing REST APIs, Java and React.

Apply hands-on experience with Kafka, including message schema design, topic partitioning, consumer group strategies, and fault-tolerant processing.

Design and govern data architecture across Oracle (SQL) and MongoDB (NoSQL), covering schema design, indexing strategies, query optimization, and data consistency patterns.

Champion continuous development, feature flags, and progressive delivery, contributing to the design and optimization of CI/CD pipelines.

Produce and review Architecture Decision Records (ADRs) and technical design documents for key platform components.

2. Engineering Excellence & Quality

Maintain and enforce engineering standards within the scrum team, including Test-Driven Development (TDD), reusable framework development, CI/CD, secure coding, and observability.

Conduct code reviews for critical platform components, providing detailed technical feedback to enhance team quality and capacity, ensuring the development of scalable and reusable services.

Drive the adoption of AI-powered quality practices, including leveraging tools like GitHub Copilot for coding, utilizing LLMs (Gemini experience preferred) to improve payment processing quality, and implementing automated test script generation and vulnerability remediation.

Lead performance engineering initiatives, including profiling JVM-based applications Java identifying performance hotspots, and optimizing critical settlement processing paths.

Own the security and compliance posture of the cheque payment platform by participating in threat modeling, vulnerability assessments, and secure design reviews.

Ensure all engineering delivery aligns with Citi Engineering Excellence Standards, including CI/CD, DevOps, cloud-native practices, and modern ways of working.

3. Platform Strategy & Domain Ownership

Define and own the engineering roadmap for modernizing the cheque payment platform, migrating global components from monolithic mainframe and legacy applications to a reusable microservices architecture.

Develop strong domain knowledge in the payment lifecycle, settlement, and cheque image processing to inform sound engineering decisions.

Own the platform's SLA commitments, driving architectural decisions to meet availability, throughput, and latency targets.

Develop cross-platform integration by governing API contracts, data flows, and system dependencies across the Payments, Settlements, DDA, and Data Lake ecosystems.

Drive capacity planning and investment prioritization, making informed decisions on platform scaling, technology refresh, and resource allocation.

Partner with Operations, Risk, Compliance, and Business teams to ensure the platform meets all regulatory requirements and business needs.

4. Leadership & Stakeholder Engagement

Act as the primary engineering point of contact for the core Cheque Processing pillar, engaging with senior business, technology, and operations stakeholders.

Clearly communicate platform health, delivery progress, engineering strategy, and risks to senior leadership.

Partner with Product, Operations, Risk, Finance, and Compliance teams to align engineering priorities with business and regulatory needs.

Demonstrate the ability to pivot direction to meet timelines and delivery commitments with tactical solutions, while maintaining a clear vision for strategic platform development.

Required Skills and Qualifications

1. Core Programming & System Architecture

Java: 10+ years of Extensive hands-on experience in high-throughput, production-grade Java engineering, including JVM performance tuning.

API Development: Hands-on experience building RESTful APIs with frameworks such as Spring MVC or Spring Boot.

Microservices Architecture: Proven experience designing microservices ecosystems, including service decomposition, API design, inter-service communication, and cloud engineering.

Event-Driven & Messaging Systems: Deep, hands-on expertise in Kafka, including topic design, partitioning, consumer groups, exactly-once semantics, and high-throughput stream processing.

High-Performance Computing: Hands-on experience with profiling and optimization, including JVM tuning, garbage collection (GC) optimization, thread management, and memory profiling.

High Availability & Fault Tolerance: Practical experience designing resilience patterns such as circuit breakers, bulkheads, failover, and disaster recovery.

Databases: Hands-on expertise in Oracle (SQL) and Microsoft SQL for schema design, query optimization, and indexing, as well as MongoDB (NoSQL) for document modeling, aggregation pipelines, sharding, and replica sets.

2. Cloud & DevOps

Cloud-Native Engineering: Hands-on experience with OpenShift/AWS, Kubernetes, and Docker for container orchestration, autoscaling, and cloud-native deployment.

CI/CD & DevOps: Experience designing and owning CI/CD pipelines aligned with enterprise-level Engineering Excellence Standards. Experience with tools like Jenkins and Gradle/Maven.

Observability: Hands-on experience with distributed tracing, intelligent alerting, and AI-driven observability using tools like Grafana.

Secure Engineering: Practical experience with threat modeling, vulnerability assessments, and secure design reviews.

Agile at Scale: Experience with Agile/SAFe delivery at the program level, including PI planning, cross-team dependency management, and delivery governance.

Good-to-Have Skills

ML Integration: Hands-on experience with real-time ML model serving, including feature stores, online inference, and model monitoring.

AI Frameworks: Familiarity with Retrieval-Augmented Generation (RAG) patterns, vector databases (e.g., Pinecone, Weaviate), or agentic AI frameworks (e.g., LangChain, AutoGen).

Resilience Testing: Experience with chaos engineering and resilience testing, including fault injection and production readiness reviews.

Financial Systems: Knowledge of reconciliation and exception handling patterns in settlement workflows.

LLM Experience: Familiarity with prompt engineering and LLM fine-tuning in a regulated enterprise context.

Legacy Modernization: Experience with large-scale transformation projects, including migrating mainframe components (COBOL, Assembler) and legacy systems (C++, .NET) to a microservices architecture.

Strategy: Experience with technology investment governance and engineering budget management.

What We Are Looking For

A hands-on leader who actively contributes to code, frameworks, reviews, and technical problem-solving.

A strategic thinker who is equally comfortable at the code/architecture level and the platform strategy/stakeholder management level.

A pragmatic innovator who identifies practical, high-value opportunities to apply AI/ML without losing focus on engineering fundamentals.

An accountable owner with a strong sense of ownership for platform quality, reliability, and delivery.

A mentor committed to developing engineers and managers, building technical capability and leadership depth across the team.

An effective communicator able to translate technical complexity into clear, concise updates for business and senior leadership.

Why Join Us

Lead engineering for a central global payment platform while remaining deeply technical.

Drive AI and engineering transformation on a high-visibility modernization initiative with significant business impact.

Work at the intersection of high-throughput financial systems and modern AI capabilities.

Build and mentor a strong engineering team with access to state-of-the-art tools, platforms, and talent.

Be part of an engineering culture that values technical depth at every level of seniority.