# Dave DeLong

> Dave DeLong is a software craftsman with fifteen years of building iOS and macOS apps that ship on billions of devices - and, he likes to point out, some that run in outer space. A seven-year Apple veteran who worked on Siri, UIKit, Apple Maps, and Developer Evangelism, he led the WWDC app from 2013 to 2015 and helped ship the first releases of Swift, WatchKit, HomeKit, and HealthKit. He is among the top contributors of all time on Stack Overflow, a fixture of the Swift Evolution process, and the author of widely cited open-source libraries on calendrical math. He blogs at davedelong.com, speaks at conferences worldwide, and is currently building a stealth startup.

- **Role:** Founder / Engineer at Stealth Startup
- **Organizations:** Stealth Startup, Apple, WeWork, Snap Inc., Syzygy Development, LLC
- **Nationality:** American
- **Education:** B.S. in Computer Science, Brigham Young University
- **Known for:** Seven-year Apple veteran across Siri, UIKit, Apple Maps, and Developer Evangelism, Lead engineer of the WWDC app from 2013 to 2015, Closely involved with initial releases of Swift, WatchKit, HomeKit, and HealthKit

## Career timeline

- **2013-2015** — Lead engineer of the WWDC app (now the Developer app) at Apple
- **2014** — Involved with initial releases of Swift, WatchKit, HomeKit, and HealthKit
- **2020** — Joined Apple's Siri organization as a Senior Software Engineer; core contributor to Siri's conversational engine runtime
- **2019** — Principal iOS Engineer at WeWork; spoke at try! Swift Tokyo, try! Swift NYC, and 360iDev
- **present** — Building a stealth startup

## Achievements

- Seven-year Apple veteran across Siri, UIKit, Apple Maps, and Developer Evangelism
- Lead engineer of the WWDC app from 2013 to 2015
- Closely involved with initial releases of Swift, WatchKit, HomeKit, and HealthKit
- Among the top 0.05% of all-time contributors on Stack Overflow (user #115730)
- Active participant in the Swift Evolution process
- Led Siri's API Review team, evaluating APIs for fitness, consistency, correctness, maintainability, and ergonomic fit
- Author of DDMathParser (800+ GitHub stars) and the Time library for calendrical calculations
- Creator of 'Your Calendrical Fallacy Is', a widely shared resource on date and time pitfalls
- Shipped code running on billions of devices, including systems used in outer space

## Latest updates

- **2025** — Listed as building a stealth startup after his tenure at Apple

## Links

- Website: https://davedelong.com
- LinkedIn: https://www.linkedin.com/in/davedelong/
- Twitter/X: https://twitter.com/davedelong
- GitHub: https://github.com/davedelong
- Instagram: https://www.instagram.com/davedelong/

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Profile page: https://yespress.io/dave-delong
Published by YesPress — https://yespress.io
Last updated: 2026-06-04