{"id":3087248,"url":"https://alion.io/job/s-i-systems-senior-typescript-developer","title":"Senior TypeScript Developer","company":{"id":3865830,"name":"S.i. Systems","domain":"sisystems.com","url":"https://alion.io/company/sisystems-2","size_band":"1001-5000","is_staffing_agency":true,"employer_type":"agency","is_intermediary":false,"listed_via":null,"ats_vendor":"ADP","truth_index":null},"role":"Frontend","role_family":"Frontend","seniority":"senior","employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Toronto, Canada"],"countries":["CA"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":70000,"max_usd":153000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":14},"experience_years_min":10,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Git","optional":false},{"name":"GraphQL","optional":false},{"name":"JavaScript","optional":false},{"name":"Jest","optional":false},{"name":"Mocha","optional":false},{"name":"Node JS","optional":false},{"name":"PostgreSQL","optional":false},{"name":"Rest API","optional":false},{"name":"TypeScript","optional":false},{"name":"Agile","optional":true},{"name":"AWS","optional":true},{"name":"Azure","optional":true},{"name":"CI/CD","optional":true},{"name":"Docker","optional":true},{"name":"GCP","optional":true},{"name":"Kubernetes","optional":true},{"name":"Rollup","optional":true},{"name":"Turborepo","optional":true},{"name":"Vite","optional":true},{"name":"Webpack","optional":true}],"status":"live","first_seen_at":"2026-10-20T05:01:43Z","employer_posted_date":null,"last_verified_at":"2026-10-20T05:01:43Z","board_verified":false,"closed_at":null,"days_open":14,"trust":{"level":"not_scored","repost_count":null,"flags":[],"days_open":14},"description":"Our investment management client is seeking a Senior TypeScript Developer (10+ years) to design and build scalable applications using TypeScript, distributed architectures, and API design\n\nJoin a software development team delivering scalable front-end and back-end applications within the financial services sector. This role focuses on TypeScript development, architectural decision-making, distributed systems, API design, and mentoring developers across complex engineering initiatives. The position offers hands-on involvement in scalable application development, performance optimization, and cross-functional collaboration.\n\nPermanent, Toronto, Working Hours: EST\nHybrid: 4 times a week on site (near Union Station)\n\nMust Haves\n10+ years of professional software development experience.\n5+ years of extensive TypeScript experience in production environments.\nStrong understanding of JavaScript fundamentals, ES6+, and asynchronous programming.\nExperience with Node.js and back-end TypeScript development.\nExtensive experience designing and building distributed architectures and microservices.\nExpert-level knowledge of API design principles, RESTful APIs, and/or GraphQL.\nStrong proficiency with PostgreSQL, including schema design, query optimization, and performance tuning.\nExperience with version control systems (Git) and collaborative development workflows.\nStrong knowledge of testing frameworks (Jest, Mocha, or similar).\nExcellent problem-solving and debugging skills.\nStrong communication skills and ability to work collaboratively in a team environment.\n\nNice to Have\nExperience with modern build tools (Webpack, Vite, Rollup) and module bundlers.\nKnowledge of containerization technologies (Docker, Kubernetes).\nExperience with cloud platforms (AWS, Azure, or GCP).\nFamiliarity with CI/CD pipelines and DevOps practices.\nUnderstanding of microservices architecture.\nExperience with monorepo management tools (Nx, Turborepo, Lerna).\nContributions to open-source TypeScript projects.\nExperience with type-driven development and advanced TypeScript features.\nKnowledge of design patterns and software architecture principles.\nExperience leading technical initiatives or projects.\n\nResponsibilities\n\nDesign, develop, and maintain robust TypeScript applications across front-end and back-end systems.\nWrite clean, maintainable, and well-tested code following best practices and design patterns.\nArchitect scalable solutions and make technical decisions that align with business objectives.\nConduct thorough code reviews and provide constructive feedback to team members.\nMentor junior and mid-level developers, fostering their technical growth.\nCollaborate with product managers, designers, and other stakeholders to translate requirements into technical solutions.\nOptimize application performance and identify bottlenecks.\nStay current with TypeScript ecosystem developments and recommend new technologies or approaches.\nContribute to technical documentation and coding standards.\nParticipate in agile ceremonies including sprint planning, standups, and retrospectives.\n\nSalary Range: $135 000 - 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