Senior GIS Developer

Our Client is seeking an experienced Senior Front-End Software Developer with strong expertise in GIS web mapping applications, ESRI technologies, and JavaScript/TypeScript development. The successful candidate will design, develop, customize, and deploy interactive web mapping solutions using VertiGIS, Geocortex, and ArcGIS technologies. The ideal candidate will have hands-on experience customizing GIS viewers, integrating mapping services, developing responsive user interfaces, and delivering accessible applications in complex enterprise environments. Key Responsibilities Design, develop, customize, and maintain interactive GIS web mapping applications. Build and extend mapping functionality using JavaScript, TypeScript, React, HTML, and CSS. Customize GIS viewers using VertiGIS Studio Web SDK, Geocortex Viewer for HTML5 SDK, and ArcGIS Maps SDK for JavaScript. Develop and deploy customized GIS viewers, mapping tools, and workflows based on business requirements. Configure and integrate ESRI Experience Builder, Web AppBuilder, VertiGIS Studio, and Geocortex Essentials. Integrate ArcGIS REST APIs, ArcGIS Server services, and ArcGIS Portal into web applications. Develop responsive, cross-browser-compatible, and accessible user interfaces. Ensure compliance with AODA and WCAG 2.0 Level AA accessibility standards. Collaborate with business stakeholders, technical teams, and subject matter experts to gather requirements and deliver solutions. Perform coding, debugging, unit testing, troubleshooting, and application maintenance. Support application deployments, integrations, migrations, and post-implementation activities. Prepare technical documentation and participate in design reviews and walkthroughs. Must-Have Skills Hands-on experience customizing web mapping applications using one or more of the following: VertiGIS Studio Web SDK (preferred) Geocortex Viewer for HTML5 SDK ArcGIS Maps SDK for JavaScript (formerly ArcGIS API for JavaScript) Strong experience developing GIS web mapping applications using JavaScript/TypeScript. Experience with ESRI GIS technologies and web mapping platforms. Strong knowledge of HTML, CSS, responsive web design, and cross-browser compatibility. Experience integrating GIS services through ArcGIS REST API, ArcGIS Server, and ArcGIS Portal. Ability to develop, customize, test, and deploy enterprise-level web applications. Preferred Qualifications Experience with VertiGIS Studio Web and Workflow. Experience with Geocortex Essentials, ESRI Experience Builder, or Web AppBuilder. Knowledge of React or similar modern JavaScript frameworks. Experience configuring GIS application workflows, permissions, and user roles. Experience developing accessible applications compliant with AODA and WCAG standards. Experience working with the Ontario Public Service (OPS) or broader public sector. Familiarity with Agile development methodologies and the software development lifecycle. Strong analytical, troubleshooting, communication, and problem-solving skills. Ability to work independently and collaboratively with cross-functional teams.