16 results for Senior Software Engineerdeveloper jobs
Senior Full Stack Developer
- Mississauga, ON
- onsite
- Permanent
-
100000 - 115000 CAD / Yearly
- <p>We are seeking a talented <strong>Senior Full Stack Developer</strong> to join our client's team in Mississauga, Ontario.</p><p><br></p><p>The successful candidate will work closely with the business to identify and define the best solutions to address challenges faced by both our customers and internal operations. The Senior Developer will translate functional and non‑functional requirements into clear designs and implementation strategies, ensuring the effective delivery of business applications. They will be responsible for the quality of all deliverables, ensuring that solutions are reliable, fit for purpose, and built to be supportable and maintainable over the long term.</p><p><br></p><p><strong>Technical Skills</strong></p><ul><li><strong>Programming:</strong> J2EE, JPA, Java Web Services (RESTful), Spring Framework, Angular, Maven</li><li><strong>Tools:</strong> Jira, Confluence, GitHub</li><li><strong>Databases:</strong> Relational database systems (ideally Oracle), PL/SQL, SQL Query development</li><li><strong>Operating Systems:</strong> Linux, HP‑UX or other UNIX variants, Windows</li><li><strong>Architecture:</strong> Experience in multi‑platform distributed environments, web‑based architectures, and microservices</li><li><strong>Design:</strong> Familiarity with standard design patterns and UML</li><li><strong>DevOps:</strong> Experience with CI/CD automation processes</li></ul>
- 2026-04-09T00:00:00Z
Software Developer
- Burnaby, BC
- onsite
- Temporary
-
0 - 0 CAD / Yearly
- <p>Our client is seeking a <strong>Software & Data Developer</strong> to help design, build, and maintain applications and data solutions that support business operations and reporting. This role blends <strong>software development and data engineering</strong>, working across systems and data platforms to enable reliable insights and scalable technology solutions.</p><p><br></p><p>This position will collaborate closely with internal IT teams and business stakeholders to develop applications, manage integrations, and ensure data is accessible, accurate, and usable across the organization.</p><p><br></p><p><strong>Responsibilities</strong></p><ul><li>Design, develop, and maintain internal applications and system integrations</li><li>Build and manage <strong>data pipelines and ETL processes</strong> across multiple data sources</li><li>Write and optimize <strong>SQL queries</strong> to support data analysis and reporting</li><li>Troubleshoot application and data issues to maintain system reliability and performance</li><li>Work with stakeholders to translate business requirements into technical solutions</li><li>Develop documentation including system diagrams, technical specifications, and test plans</li><li>Support integrations with enterprise platforms such as <strong>ERP and CRM systems</strong></li></ul><p><br></p><p><br></p>
- 2026-05-01T00:00:00Z
Senior Application Security Engineer (Offensive Security)
- Toronto, ON
- onsite
- Permanent
-
120000 - 140000 CAD / Yearly
- <p>This is a hybrid opportunity (2–3 days per week onsite) based in Downtown Toronto.</p><p>Are you ready to help shape and grow an innovative Offensive Security team?</p><p><br></p><p>We are seeking an experienced cybersecurity professional who specializes in offensive security, application testing, and threat management within modern technology stacks—including low code/no code platforms and AI/ML pipelines.</p><p>In this strategic role, you will lead efforts to identify vulnerabilities, simulate adversarial threats, and enhance the organization's security posture across its cloud, application, and AI/ML environments. Candidates with proven success building offensive security teams, driving penetration testing and incident response programs, and securing AI/ML workflows are encouraged to apply.</p><p><br></p><p><strong>Key Responsibilities:</strong></p><ul><li>Lead and execute penetration tests on low code/no code platforms, uncovering misconfigurations and privilege escalation issues.</li><li>Conduct targeted assessments of AI/ML pipelines, models, and data flows to identify security gaps.</li><li>Evaluate CI/CD integrations and MLOps environments with a focus on risk mitigation.</li><li>Analyze web and mobile applications for vulnerabilities, including insecure APIs and injection threats.</li><li>Perform threat modeling and code analysis to support vulnerability remediation.</li><li>Monitor and respond to security incidents using SIEM technologies such as Splunk and Azure Sentinel.</li><li>Develop use cases that anticipate emerging threats, especially those related to AI/ML attack vectors.</li><li>Utilize industry-standard tools—Burp Suite, OWASP ZAP, Checkmarx, Veracode, Snyk—for comprehensive vulnerability assessments.</li><li>Conduct offensive API testing and simulate real-world adversarial scenarios.</li></ul>
- 2026-04-07T00:00:00Z
.NET Software Developer
- Vancouver, BC
- onsite
- Permanent
-
100000 - 120000 CAD / Yearly
- <p>This is an opportunity to join the core product development team with a well-established software company. This company operates successfully across the US and Canada, and they are adding team members to their Vancouver operations. </p><p><br></p><p>In this role, you’ll be working with several other software developers to develop features for the platform. You’ll be working primarily with .NET and C# as the main technologies. In addition, you’ll be working with several other tools related to CI/CD and observability. This company really values data in their design and decision making process.</p><p><br></p><p>This job is suitable if you are an experienced software developer with five or more years of recent, hands-on work experience as a hands-on software developer, with a previous for .NET and C#. </p><p><br></p><p>This company operates in a hybrid work environment, and you’ll split your time between your home office, and your office in downtown Vancouver. </p><p><br></p><p>This is a full-time position, and includes a competitive base salary, paid vacation and extended health and dental benefits.</p><p><br></p><p><strong>How to Apply</strong></p><p><br></p><p>A bit about myself - my name is Nathan Wawruck, and I am a recruitment consultant based in Vancouver, BC. I have over a decade of matching software and IT professionals to job opportunities, and I am always looking to connect with like-minded people in the Vancouver area.</p><p><br></p><p>If you're interested in pursuing this role, please apply to this posting online, and contact me for an initial discussion. This is a chance for us to discuss specifics, such as the company name, the key hiring managers, and the more in-depth job requirements. This is also a great opportunity to talk about your overall career goals and preferences. We can even discuss other potential roles which may fit what you're looking for. Please find me on LinkedIn by searching my name: Nathan Wawruck</p>
- 2026-04-30T00:00:00Z
.NET Software Developer
- Vancouver, BC
- onsite
- Permanent
-
80000 - 90000 CAD / Yearly
- <p>Are you a software developer who likes working on a wide variety of projects for different customers? Would you also like to have the stability of a full-time position with a well-established, boutique software solutions consulting company? Well this role offers both variety and stability, and a chance to work with some of the latest and greatest .NET and Azure services.</p><p><br></p><p>In this .NET Software Developer role, you will work on various software development projects for a spectrum of client companies mostly based in the Vancouver area. This job is well-suited if you are an experienced software engineer who is comfortable working on end-to-end software development projects, including requirements analysis, design, coding and testing. This is an environment where you can really 'own' your projects. </p><p><br></p><p>You will be working primarily with C#, .NET and MS Azure services in this position.</p><p><br></p><p>This is a full-time position that includes a competitive base salary, extended health and dental benefits, and paid vacation. </p><p><br></p><p>This leadership team at this company are experienced and supportive software professionals, and this means you will have lots of learning opportunities from the leaders and other developers in the office. The learning will also come from the fact that you’ll work on a wide variety of projects for different customers during the year. Overall, it is a great chance for you to experience being a software consultant, with the backing and security of a full-time job.</p><p><br></p><p><strong>How to Apply</strong></p><p><br></p><p>A bit about myself - my name is Nathan Wawruck, and I am a recruitment consultant based in Vancouver, BC. I have over a decade of matching software and IT professionals to job opportunities. Whenever possible I prefer to meet face-to-face (well, virtually for now), and I am always looking to connect with like-minded tech enthusiasts in the Vancouver area</p><p><br></p><p>If you're interested in pursuing this role, the first step is to apply online. If your qualifications are a match, we can arrange time to discuss specifics, such as the company name, the key hiring managers, and the more in-depth job requirements. This is also a great opportunity to talk about your overall career goals and preferences. We can even discuss other potential roles which may fit what you're looking for. Please find me on LinkedIn by searching my name: Nathan Wawruck</p>
- 2026-04-30T00:00:00Z
Software Development Project Manager
- Vancouver, BC
- onsite
- Permanent
-
100000 - 120000 CAD / Yearly
- <p>We are seeking a Software Development Project Manager to join our clients Technology team in Vancouver. This company operates successfully across the North America and Europe, and they are looking to add a technically strong Project Manager to lead and oversee multiple concurrent software development projects.</p><p> </p><p>In this role, you’ll be working closely with a cross‑functional software development team to deliver high‑quality software products and solutions. You’ll coordinate work across developers and product stakeholders, clearly translating requirements, validating completed features, and keeping delivery on track. The role requires close collaboration with technical teams, comfort working across time zones when needed, and a solid understanding of modern software development practices.</p><p> </p><p>This job is suitable if you have experience managing multiple software development projects, a strong record of delivering to scope and timelines, and hands on exposure to Agile delivery, stakeholder communication, and modern cloud based development environments.</p><p> </p><p>This company operates in a hybrid work environment, and you’ll split your time between your home office, and your office in downtown Vancouver. </p><p> </p><p>This is a full-time position, and includes a competitive base salary, paid vacation and extended health and dental benefits.</p><p> </p><p><strong>How to Apply</strong></p><p> </p><p>A bit about myself - my name is Nathan Wawruck, and I am a recruitment consultant based in Vancouver, BC. I have over a decade of matching software and IT professionals to job opportunities, and I am always looking to connect with like-minded people in the Vancouver area.</p><p> </p><p>If you're interested in pursuing this role, please apply to this posting online, and contact me for an initial discussion. This is a chance for us to discuss specifics, such as the company name, the key hiring managers, and the more in-depth job requirements. This is also a great opportunity to talk about your overall career goals and preferences. We can even discuss other potential roles which may fit what you're looking for. Please find me on LinkedIn by searching my name: Nathan Wawruck</p>
- 2026-04-28T00:00:00Z
Web Developer
- North York, ON
- onsite
- Temporary
-
28.5 - 33 CAD / Hourly
- We are looking for a Web Developer to lead the planning, design, and development of a modern web presence for an organization based in Toronto, Ontario. This Long-term Contract opportunity is suited to a detail-oriented individual who can combine strategic website planning with hands-on technical delivery, from user experience improvements to custom WordPress development. The successful candidate will help create an accessible, secure, and scalable platform that supports public engagement and member services while meeting bilingual and long-term maintenance needs.<br><br>Responsibilities:<br>• Evaluate the current Drupal website, gather input from key stakeholders, and translate business needs into a practical web strategy.<br>• Recommend an improved bilingual platform approach, including site structure, navigation flow, and content organization that supports usability and growth.<br>• Prepare visual concepts and mock-ups, lead feedback sessions, and refine the user experience in alignment with organizational branding.<br>• Develop custom WordPress themes and plugins, using modern HTML, CSS, JavaScript, and related front-end practices to improve accessibility and engagement.<br>• Configure and connect third-party tools, APIs, and membership-related functionality to support events, resources, and restricted-access content.<br>• Design and maintain secure, efficient data structures and support both client-side and back-end integrations required for website functionality.<br>• Enhance website performance through optimization for speed, scalability, security, privacy, and accessibility compliance with WCAG 2.1 AA standards.<br>• Lead the migration of content and data from Drupal to WordPress while preserving metadata, page hierarchy, and secure member access, followed by detailed quality assurance testing.<br>• Deliver staff training, written documentation, and practical guidance on content updates, maintenance tasks, account administration, and management of event and resource pages.<br>• Collaborate with cross-functional teams to provide project timelines, status updates, issue tracking, and post-launch support recommendations.
- 2026-04-23T00:00:00Z
Web Developer
- Calgary, AB
- remote
- Temporary
-
47.5 - 55 CAD / Hourly
- <p>Our client is seeking a skilled Full Stack Developer to support the development of modern, API-driven applications on a remote 12-month contract. This role will focus primarily on backend development using Node.js and GraphQL, with some collaboration on front-end components.</p><p><br></p><p>The ideal candidate is highly self-sufficient, comfortable working autonomously, and able to deliver high-quality solutions with minimal oversight.</p><p><br></p><p><strong>Key Responsibilities</strong></p><ul><li>Design, develop, and maintain backend services using <strong>Node.js</strong></li><li>Build and optimize <strong>GraphQL APIs</strong>, ensuring efficient data delivery and structure</li><li>Collaborate with front-end developers to support seamless integration and user experience</li><li>Contribute to front-end development where required, particularly in customer-facing applications</li><li>Ensure code quality, scalability, and performance across applications</li><li>Partner with technical leadership on solution design and implementation</li></ul><p><br></p>
- 2026-04-22T00:00:00Z
Senior Database Administrator
- Mississauga, ON
- onsite
- Permanent
-
95000 - 115000 CAD / Yearly
- <p>We are looking for an experienced Senior Database Administrator to support an organization in Mississauga, Ontario. This position is suited to a senior technical specialist who can strengthen database reliability, guide architectural decisions, and improve performance across enterprise environments. The role works closely with delivery teams and business partners to ensure database solutions are scalable, secure, and aligned with operational priorities.</p><p><br></p><p>Responsibilities:</p><p>• Establish and oversee database performance and capacity strategies, including standards that support long-term stability and growth.</p><p>• Partner with project managers, developers, and business analysts to deliver database components for concurrent business and technology initiatives.</p><p>• Investigate and resolve production database issues, including performance concerns linked to application code and data processing.</p><p>• Create detailed testing approaches and maintain reusable scripts to validate database changes before release.</p><p>• Review requested changes, assess downstream impact, and provide informed estimates for effort, timelines, and implementation considerations.</p><p>• Develop and maintain automation and support scripts using Perl, shell scripting, and PL/SQL for monitoring, maintenance, and operational support.</p><p>• Design and implement database architecture across development, test, and production environments to ensure consistency and resiliency.</p><p>• Participate in an after-hours support rotation to address urgent database incidents and maintain service continuity.</p>
- 2026-04-29T00:00:00Z
AI Staff Software Engineer
- Toronto, ON
- onsite
- Permanent
-
120000 - 140000 CAD / Yearly
- <p>We are looking for an experienced <strong>AI Staff Software Engineer t</strong>o join our team in Toronto, Ontario. In this role, you will lead the development and deployment of advanced AI systems, ensuring their integration across multiple platforms and teams. The ideal candidate will have deep expertise in AI technologies, strong problem-solving skills, and an ability to drive technical innovation in ambiguous environments.</p><p><br></p><p><strong>Responsibilities</strong>:</p><p>• Design and implement cutting-edge AI systems with a focus on agentic AI technologies and workflows.</p><p>• Develop robust backend systems, APIs, and data pipelines to support scalable AI solutions.</p><p>• Collaborate with multidisciplinary teams to align technical strategies and ensure seamless integration across products.</p><p>• Lead the development of AI models and infrastructure, including planning, memory, tool usage, and evaluation.</p><p>• Optimize cloud infrastructure to enhance system reliability and performance.</p><p>• Translate complex problems into actionable solutions, delivering autonomous systems that meet business objectives.</p><p>• Mentor and guide engineering teams through advanced AI workflows and development processes.</p><p>• Drive technical innovation while ensuring the stability and scalability of deployed systems.</p><p>• Implement and manage workflow engines, asynchronous processing, queues, and streaming systems.</p><p>• Influence technical direction and foster collaboration across teams without formal authority.</p>
- 2026-04-09T00:00:00Z
Senior Data Integration Specialist
- Calgary, AB
- onsite
- Permanent
-
130000 - 135000 CAD / Yearly
- <p><strong>THE ROLE:</strong> </p><p>We’re seeking a Senior Data Integration Specialist to bring deep expertise in data pipelines, integration workflows, and client-facing technical support. In this role, you’ll strengthen data delivery processes, support client onboarding, and collaborate across teams to enhance how data products are built, delivered, and consumed. This position combines advanced technical skills with strong communication and problem-solving abilities.</p><p><em>Key Responsibilities</em></p><ul><li>Work with data across Oracle, Postgres, Snowflake, Elasticsearch, and Azure SQL</li><li>Refine and maintain internal data pipelines and ETL/ELT processes</li><li>Prepare and structure data for analytics tools (e.g., Power BI) and internal applications</li><li>Document integration workflows, mappings, and pipeline designs for reuse and knowledge sharing</li><li>Act as a technical resource to client-facing teams and provide guidance during data integrations</li><li>Support clients as they transition from legacy delivery methods to modern Postgres-based solutions</li><li>Help clients understand underlying data structures and apply them effectively</li><li>Share insights with product and data teams to influence future offerings</li><li>Mentor junior staff and contribute to cross-team collaboration on innovative data solutions</li></ul><p><strong>WHY THIS ROLE?</strong></p><p>This position offers the opportunity to work with cutting‑edge data platforms, partner directly with clients, and influence the direction of innovative data products. You’ll join a team that values collaboration, technical curiosity, and continuous improvement. The role provides competitive compensation, full benefits, and opportunities for long‑term professional growth within a forward‑thinking data organization. Are you passionate about data and love solving complex integration challenges? Then we encourage you to apply now!</p>
- 2026-04-20T00:00:00Z
Software Developer - MAUI and BLAZOR
- Vancouver, BC
- remote
- Permanent
-
90000 - 120000 CAD / Yearly
- <p>Have you been looking for an opportunity to join an experienced team of software developers, and work on a software-as-a-service product? This is a chance to apply your software development skills and work in a well-established Vancouver-based company.</p><p><br></p><p>The focus of this role will be on using Microsoft’s BLAZOR and MAUI frameworks, to develop a full-suite of mobile and web applications, including desktop, iPhone, iPad, Android and responsive web. </p><p><br></p><p>So if you’re an experienced developer who has been looking for a chance to dive deeper in to MAUI and BLAZOR then please read on.</p><p><br></p><p>As part of the core product development team, you will be coding and implementing features in a mature, web-based software application. Your focus will be on developing various client-side versions of the software interface, using BLAZOR and MAUI.</p><p><br></p><p>This is a full-time position that includes a competitive base salary, extended health and dental benefits, and paid vacation. </p><p><br></p><p>One of the attractive parts of this job is the chance to learn from other experienced members of the team. This team works collaboratively to solve technical problems together. You will also see your efforts show up in the real-world product, since your code will have a direct impact on the shape of the product. </p><p><br></p><p><strong>HOW TO APPLY</strong></p><p><br></p><p>A bit about myself - my name is Nathan Wawruck, and I am a recruitment consultant based in Vancouver, BC. I have over a decade of matching software and IT professionals to job opportunities, and I am always looking to connect with like-minded tech enthusiasts in the Vancouver area</p><p><br></p><p>If you're interested in pursuing this role, please contact me for an initial discussion. This is a chance for us to discuss specifics, such as the company name, the key hiring managers, and the more in-depth job requirements. This is also a great opportunity to talk about your overall career goals and preferences. We can even discuss other potential roles which may fit what you're looking for. Please find me on LinkedIn by searching my name: Nathan Wawruck</p><p><br></p><p><strong>REQUIREMENTS</strong></p><p><br></p><p>Here are some of the items that you'll bring to the table for this role: </p><p><br></p><ul><li>You have five or more years of recent, hands-on coding experience with C# and .NET framework</li><li>You have recent hands-on experience with MAUI, with a focus on mobile (iOS and Android) and web application development</li><li>Knowledge of BLAZOR would be considered an asset</li></ul><p><br></p>
- 2026-05-01T00:00:00Z
D365 F&O Platform Engineer
- Toronto, ON
- onsite
- Permanent
-
110000 - 120000 CAD / Yearly
- <p><strong>This is a hybrid opportunity (2–3 days per week onsite) based in Downtown Toronto. Are you ready to help build an innovative, global ERP team? </strong></p><p><br></p><p>We are looking for an experienced D365 F&O Platform Engineer for our client in Toronto, Ontario. In this role, you will apply your expertise in Microsoft Dynamics 365 Finance & Operations to support, troubleshoot, and implement ERP systems. If you have a strong background in techno-functional solutions and a passion for optimizing business processes, this opportunity is perfect for you. </p><p> </p><p><strong>Responsibilities</strong>: </p><p>• Provide technical and functional support for Microsoft Dynamics 365 Finance & Operations, ensuring smooth system operations. </p><p>• Troubleshoot system issues and resolve technical challenges directly within the application. </p><p>• Assist end users by addressing their queries and providing solutions in a production environment. • Collaborate on the implementation and maintenance of system modules, workflows, and security roles. </p><p>• Utilize Lifecycle Services, Azure DevOps, and Power Platform tools to manage and improve ERP performance. </p><p>• Develop and maintain electronic reporting frameworks and data management strategies. </p><p>• Participate in the integration of Power Platform and Dataverse to enhance system functionality. </p><p>• Perform basic object-oriented programming tasks to support system customizations. </p><p>• Generate reports and dashboards using Power BI for data visualization and decision-making. </p><p>• Work with support tickets to ensure timely resolution and documentation of issues.</p><p><br></p><p><br></p>
- 2026-04-10T00:00:00Z
Bilingual Learning Developer
- Mississauga, ON
- remote
- Temporary
-
38 - 46 CAD / Hourly
- <p>We are seeking a <strong>Bilingual Learning Developer (French/English)</strong> to support the design and development of engaging learning experiences for our client. This short-term contract role is ideal for someone with a strong <strong>instructional design background</strong> who can translate learning objectives into effective digital learning solutions. The successful candidate will work closely with subject matter experts and stakeholders to create clear, engaging, and accessible learning materials in both <strong>English and French</strong>.</p><p><br></p><p>Contract: 3 months to start, opportunities to extend</p><p>Location: Remote, work in EST hours (Candidates must be local to the Greater Toronto Area or Montreal) </p><p><br></p><p><strong>Key Responsibilities</strong></p><ul><li>Design and develop learning solutions such as eLearning modules, job aids, facilitator guides, and microlearning resources.</li><li>Apply <strong>instructional design methodologies</strong> (e.g., ADDIE, adult learning principles) to create effective learning experiences.</li><li>Collaborate with subject matter experts to gather content and translate it into engaging learning materials.</li><li>Develop and adapt learning content in <strong>both English and French</strong>, ensuring linguistic accuracy and cultural appropriateness.</li><li>Review and update existing training materials to improve clarity, engagement, and effectiveness.</li><li>Ensure learning content meets accessibility and quality standards.</li></ul>
- 2026-04-23T00:00:00Z
Senior Fraud Analyst
- North York, ON
- onsite
- Permanent
-
90000 - 110000 CAD / Yearly
- <p>Our client is looking to hire a Senior Fraud Analyst in the Greater Toronto area. The roe will work closely with stakeholders to set up the appropriate framework to mitigate fraud, build out capabilities, tools, and methods for preventing fraud. </p><p><br></p><p>Responsibilities Include: </p><p><br></p><p>• The ideal candidate would partner with stakeholders across the organization to ensure a strong approach to fraud management. </p><p>• Analyze trends and discover patterns to identify potential fraud risks and make strong recommendations. </p><p>• Recommend and assist with implementation of improvements to boost fraud detection and prevention capabilities across the organization. </p><p>• Work closely with Operations, Credit, Risk to address fraud related issues and recommend improvements to existing controls and processes to mitigate risks. </p>
- 2026-04-04T00:00:00Z
Senior Financial Analyst
- Edmonton, AB
- onsite
- Temporary
-
0 - 0 CAD / Yearly
- <p><strong>THE ROLE:</strong> </p><p>Our Edmonton based client is looking for a Senior Financial Analyst with deep financial modeling expertise to rebuild existing models and design new ones that support decision‑making, forecasting, and business strategy. This role is ideal for someone who enjoys untangling legacy models, improving assumptions, and building scalable, reliable tools for leaders.</p><p><em>What You’ll Do:</em></p><ul><li>Rebuild and enhance existing financial models</li><li>Design new financial models aligned to evolving business needs</li><li>Validate assumptions, logic, and calculations to ensure accuracy and integrity</li><li>Partner with Finance and operational leaders to translate requirements into usable models</li><li>Create clear documentation and model structures for long‑term use</li><li>Provide insights and recommendations based on model outputs</li></ul><p><strong>ABOUT YOU:</strong></p><p>You are a detail‑oriented, analytical finance professional who enjoys solving complex problems and bringing clarity to messy or outdated models. You are comfortable working independently, partnering with non‑finance stakeholders, and clearly explaining financial outputs. Organized and adaptable, you thrive in dynamic environments where priorities evolve and strong communication is key.</p><p><br></p><p><strong>WHAT'S ON OFFER?</strong></p><p>A competitive wage is offered, aligned with experience and expertise. This contract role provides the opportunity to make a meaningful impact by improving the quality and usability of financial models that directly support leadership decisions. It’s an excellent fit for a senior‑level analyst who enjoys hands‑on, analytical work and high‑value problem solving. Don't miss out on this chance to be a driving force behind financial excellence. Submit your details online today!</p>
- 2026-04-30T00:00:00Z