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Hello, I'm

Peramanathan Sathyamoorthy

Senior Software Engineer

Senior Software Engineer with 9+ years in scalable web apps, JavaScript, ReactJS, and system architecture, leading teams and mentoring in innovative startups.

View My WorkView CV

About Me

Professional summary

Senior Software Engineer with over 9 years of experience in building scalable web applications and leading development teams. Holds Master's degrees in Computer Science and Operations Research, providing a strong foundation in both theoretical and applied aspects of technology and optimization. Proven expertise in JavaScript, ReactJS, Architectural Design and System Building. Demonstrated leadership in integrating innovative solutions and driving efficiency in startup environments. Experienced educator with a passion for mentoring and fostering innovation through technology.

Focus areas

  • Engineering Leadership
  • TypeScript Integration
  • Team Mentoring
  • API Architecture

How I work

  • Clean Code

    Writing maintainable, scalable code that stands the test of time.

  • Innovation

    Always exploring new technologies and creative solutions.

  • Collaboration

    Working effectively with teams to deliver exceptional results.

  • Performance

    Building fast, optimized applications for the best user experience.

Credentials

Grok and coding agents are becoming mostly sufficient even for advanced work. Well-crafted courses — built with deliberate team effort and AI assistance — still offer powerful leverage. They compress extensive research, impose useful structure, and surface new ways of thinking, saving the learner significant time and friction. What ultimately matters most is the learner’s own curiosity and interest. The highest-value courses deliver outcomes that are highly applicable, pragmatic, and relevant to the current state of the art — creating positive impact for both the individual and society while remaining cost-effective.

— Peramanathan Sathyamoorthy

Proof of self-directed learning I've applied at work and in personal projects—and championed with teams when the fit is right.

Recent courses

  • Cilium AI/ML Security

    AI/ML Security

    Mar 2026

  • Build LLM Apps with LangChain.js

    AI

    Sep 2024

  • HashiCorp Terraform Associate Exam Cram [O'Reilly Live Event] 2 days Live Course

    DevOps

    Sep 2024

  • LangChain Chat with Your Data

    AI

    Sep 2024

Featured certificates

  • Just JavaScript

    Sep 2021

    View

  • Testing JavaScript

    May 2021

    View

  • Build an Epic React App

    May 2021

    View

  • React Suspense

    Nov 2020

    View

Professional Experience

Nine-plus years building products, leading teams, and shipping scalable systems in startup and product environments.

Career at a glance

  1. 2023Senior Software EngineerOneflow AB
  2. 2021Engineering Team LeadOneflow AB
  3. 2019Full Stack Integration EngineerOneflow AB
  4. 2017JavaScript DeveloperOneflow AB
  5. 2016Full Stack DeveloperWeavler AB
  6. 2015Software Engineer Intern (Summer Project)Bumbee Labs AB

  1. Senior Software Engineer

    Oneflow AB, Digital Signature and Contract Management Platform

    Location
    Stockholm, Sweden
    Dates
    January 2023 – December 2024
    Duration
    24 months

    Key achievements

    • Strategically integrated TypeScript into a mixed legacy codebase with FlowType and JavaScript, resulting in a 70% reduction in type-related errors, significantly enhancing code reliability and maintainability. Leveraged previously introduced Zod’s type inference for robust type hinting in business data
    • Automated the conversion of JavaScript modules to TypeScript with a custom script preserving the version control history, saving over 200 hours of manual work and accelerating development timelines
    • Unified distributed ACL permissions into a single utility module, managing complex contexts and user roles (owner, guest) to simplify maintenance, migration and enhance scalability.

    Technologies & tools

    • TypeScript
    • ReactJS
    • Python

  2. Engineering Team Lead

    Oneflow AB

    Location
    Stockholm, Sweden
    Dates
    October 2021 – December 2022
    Duration
    15 months

    Key achievements

    • Co-led the development of a new JSON-based rich text editor seamlessly integrating with legacy HTML, increasing user satisfaction by 60% and providing a modern, cohesive editing experience.
    • Mentored and empowered the development team to a self-organizing model, overseeing hiring and onboarding while instilling a continuous improvement culture. This resulted in increased productivity, stronger ownership, and scalable team practices.
    • Pioneered an end-to-end testing transformation with Playwright, starting with an innovative approach to replicate mob testing scenarios. This significantly reduced regressions and boosted efficiency. Later, I spearheaded a complete rewrite of the end-to-end testing suite in Playwright.
    • Engineered a lightweight Zod-based data validation library which streamlined data validation and minimized runtime errors.

    Technologies & tools

    • JavaScript
    • TypeScript
    • Python
    • ReactJS
    • Webpack
    • Jest
    • Zod
    • Testing-library
    • Playwright
    • MySQL
    • Nodejs
    • Express.js
    • Flask

  3. Full Stack Integration Engineer

    Oneflow AB

    Location
    Stockholm, Sweden
    Dates
    March 2019 – September 2021
    Duration
    31 months

    Key achievements

    • Established the Integration Team from the ground up, creating foundational processes and best practices for long-term scalability, while strategically aligning integration solutions with business needs.
    • Designed multi-client applications with Python and React.js, facilitating seamless integrations with platforms like HubSpot and SuperOffice, expanding Oneflow’s reach and interoperability. Helped Microsoft Dynamics and Salesforce Development with reviews and frontend decision making. Built connector application extensions for the CRM integrations and Teamtailor
    • Stabilized and enhanced the Public API, which enabled a robust third-party integration ecosystem, contributing to client satisfaction and platform versatility.

    Technologies & tools

    • Python
    • Reactjs
    • CRMs (HubSpot, SuperOffice, Microsoft Dynamics, Salesforce)
    • Connexion

  4. JavaScript Developer

    Oneflow AB

    Location
    Stockholm, Sweden
    Dates
    April 2017 – February 2019
    Duration
    23 months

    Key achievements

    • Innovatively Integrated React Router into a Backbone.js-based client to build Identity and Access Management, facilitate faster prototyping cross-linked user management and efficient testing.
    • Optimized CI build processes, reducing build times by 40%,
    • Contributed to modernizing the legacy codebase by transitioning to React.js.

    Technologies & tools

    • Python
    • Reactjs

  5. Full Stack Developer

    Weavler AB, An accessible e-commerce artisans platform (with 1.6M SEK PTS grant)

    Location
    Stockholm, Sweden
    Dates
    January 2016 – March 2017
    Duration
    15 months

    Key achievements

    • Managed AWS cloud infrastructure, reducing operational costs by 40%.
    • Integrated services like Mandrill, Slack bots, and PayPal, improving platform functionality. Implemented SEO strategies with server-side rendering.
    • Designed responsive email templates for email clients and browsers.
    • Created an intelligent notification and chat bot for onboarding and FAQs. Developed a open source babel plug-in to quickly implement translations to the entire project. Enhanced accessibility with text customization and color filters, aligned with WCAG standards. Experimented advanced features like speech synthesis and recognition, improving accessibility.

    Technologies & tools

    • JavaScript
    • Express
    • Reactjs
    • Alt.js
    • Accessibility
    • SSR
    • MongoDB
    • Babel Plugin(OSS)

  6. Software Engineer Intern (Summer Project)

    Bumbee Labs AB

    Location
    Stockholm, Sweden
    Dates
    July 2015 – September 2015
    Duration
    3 months

    Key achievements

    • Applied MongoDB aggregation and map-reduce to generate structured reports from millions of raw data samples.
    • Enhanced full-stack dashboard with gulp build and key performance indicators.
    • Explored migrating tech stack to Reactjs and Eve Python framework.

    Technologies & tools

    • MongoDB
    • AngularJS
    • Python
    • Heroku
    • Laravel (PHP)
    • System Monitoring

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