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John Aaron Nelson

Senior Full Stack Engineer • Technical Leadership • AI/Platform

Full-stack engineer and technical leader with 15+ years building products, scaling teams, and shipping high-impact initiatives. Strengths in React/TypeScript, modern web architecture, experimentation/growth, developer tooling, and pragmatic AI integration.

Experience

Senior Full Stack Engineer — Calendly
Jan 2025 - Aug 2026
  • Owned revenue-impacting Growth initiatives across frontend + backend for the category-leading scheduling product
  • Shipped experiments driving more than $1 million in ACV in 2025; improved instrumentation and analysis workflows to reduce iteration time from weeks to days
  • Drove organization-wide AI adoption (+100% usage) through internal talks, enablement, and building foundational tooling and integrations
  • Built AI tooling and infrastructure to support development with Cursor, enabling capability discovery and improved DX
  • Led rollout safety, observability, and reliability improvements; helped my team maintain a 6-month stretch with 0 customer-impacting incidents
Lead Frontend Engineer — Pipedream
Dec 2021 - Dec 2024
  • Led frontend engineering for a developer automation platform used by hundreds of thousands of developers; mentored and led execution across a team of 5
  • Project lead for growth-driving initiatives across core workflow-building experiences (editor, debugging, core UX), helping drive product adoption growth by >30%
  • Drove frontend architecture and platform quality, raising the bar for reliability and long-term maintainability
  • Reduced user friction and support burden by simplifying key UX flows and strengthening workflow-building ergonomics
Fractional CTO — Voiz Academy
Jan 2024 - Jan 2025 (fractional, concurrent)
  • Led the transformation from Notion-based workflows into a production SaaS, shipping a production MVP and migrating core operational workflows into the platform
  • Architected the system to scale operationally and technically, enabling the business to service 1,000+ users
  • Hired and led an engineering team of 4, then recruited and hired the next CTO to lead the next phase of the product
Lead Frontend Engineer — Batch.sh (YC W20)
Oct 2020 - Dec 2021
  • Led frontend development for an early-stage cloud infrastructure and deployment platform (YC W20), owning core product UX end-to-end
  • Built the website, web app, and Electron desktop app in TypeScript, all interfacing with the same backend/API surface (gRPC + Go + Kafka)
  • Designed and shipped interfaces for provisioning, deployments, and pipeline management, turning complex infrastructure workflows into a usable self-serve experience
Senior Software Engineer — Charm.io
Apr 2020 - Dec 2020
  • Designed and implemented an enterprise ETL and enrichment pipeline for a handful of key customers, enriching company and account data at scale
  • Built scalable data processing workflows (Kafka + Node.js) handling millions of records daily, with a focus on correctness, idempotency, and operability
  • Provided senior technical leadership during a critical transition period, stabilizing systems and helping the team ship reliably
Senior Salesforce Engineer — Clearbit
Feb 2018 - Apr 2020
  • Owned Clearbit's Salesforce Integration suite end-to-end; a core revenue-driving product with deep customer impact
  • Modernized legacy CoffeeScript applications into a stable React + TypeScript codebase, improving developer velocity and driving production issues to effectively zero
  • Rebuilt key surfaces as Salesforce Lightning Web Components, improving UX/performance and setting a new technical direction for the product
Software Engineer Consultant — Carbon Five
Jun 2017 - Jan 2018
  • Built enterprise marketing applications for Gap using Angular, TypeScript, and RxJS
  • Designed and implemented Kafka-backed integrations with Java warehouse and inventory management systems
  • Delivered systems supporting large-scale distribution and logistics operations, partnering closely with stakeholders across product and engineering

Earlier (2004 - 2017): Salesforce Developer Consultant, CodeScience, Inc.; Application Developer, WDD Software Solutions; Web Developer, HealthCare Strategies, Inc. At CodeScience I created ForceCode, an open-source VS Code extension for Salesforce development.

Independent: shipped Fícha, an iOS app for Rioplatense Spanish (App Store).