Josh CartmellFront-End Engineer CV

Slack

Senior Front-End Engineer > Staff Front-End Engineer

Led performance initiatives reducing CI typechecking from 7.5 to 1.75 mins (tsgo migration) and build times by 30% (SWC, Webpack 5). Architected Cypress testing initiative preventing 15+ production incidents. A/B tested React performance improvements by running experiments reducing forced layouts. Delivered TypeScript curriculum to 30+ engineers. Drove react hook adoption. Mentored 3 engineers (2 promoted). Created tooling to auto-generate type-safe API fetchers which now powers 90+% of Slack's front-end API calls. DRI for 5+ cross-functional architecture initiatives. Expert incident commander.

Quantifind

Front-End Engineer > Front-End Architect

Led 4-person front-end team through technology modernization for banking sector expansion. Architected D3/Polymer/Node.js visualization platform serving financial professionals. Designed API specifications adopted by backend teams. Established front-end hiring standards, interviewed many candidates.

Mezzanine Core Team

Open Source Developer

Core team member since 2015 and contributor to a Django CMS with 4.8k stars. Lead contributor on mailing list with 100s of questions answered. Triage tickets, wrote tutorials, develop features, and guide community development.

Bit of Pixels LLC

Web Developer/Owner

Founded and ran a web development agency. Managed clients, subcontractors, and project delivery. Specialized in design-to-code conversion and Django/Mezzanine CMS integration with custom Python backend development.

Raindrop Marketing

Lead Full Stack Engineer

Led development for multiple client websites including Coronado School District and San Diego Symphony. Built solutions ranging from brochureware to complex e-commerce and booking platforms.

Mips Computation

Web Engineer

Led all web development for a boutique firm. Created a CRM solution for large charity and dating website. Learned Python, JavaScript, HTML, and CSS.

Typescript Go

Led adoption of TypeScript Go at Slack, reducing front-end CI typechecking from 7.5 to 1.75 mins. Submitted [multiple upstream issues](https://github.com/microsoft/typescript-go/issues?q=is%3Aissue%20joshcartme) and became a [contributor](https://github.com/microsoft/typescript-go/pull/1004) to unblock adoption. Trained engineers on tsgo debugging and created a GitHub Action to custom build the tsgo extension for use in IDEs it doesn't natively support.

Chaos Cubes Game Engine

Architected a browser-based game from scratch using TypeScript, Lit, and D3. Game state managed by a Lit component, rendering by D3. Probability-based mechanics scaled to refresh rate and screen size for consistent difficulty across devices.

Front-End Rollbacks

Improved Slack resilience by updating the front-end release process to retain older builds. Reduced front-end rollback time from hours to minutes when production issues occur.

GovSlack CDN

Unlocked increased FedRAMP status for Slack by making CDN for front-end assets dynamic. Reworked how the CDN was accessed, replacing hardcoded CDN assumptions throughout the codebase.

Quantifind.com

Developed Quantifind.com using Pjax with Mezzanine for seamless page transitions. Created custom JavaScript execution system for dynamic content loading.

Oxfam America

Built reusable calendar system for Oxfam's website. Consulted on Mezzanine CMS optimization strategies.