# Donn Felker

> Think clearly. Build freely. Adapt faster. Software developer, author, and podcaster with 25+ years of experience, writing about the psychology of doing your best work while everything changes: thinking clearly, working for yourself, and doing real work while AI rewrites the rules.

Donn Felker is a software developer who has built products for some of the
most recognizable brands in the industry. He's the author of *Android
Application Development for Dummies* and *Android Tablet Application
Development for Dummies*, a contributor to *Android Developer Tools
Essentials*, and co-host of the [Fragmented Podcast](https://fragmentedpodcast.com),
a podcast for software developers. He also built TRXN (now retired), payment
infrastructure for the agent economy: a full system with an API payment
gateway, OFAC and SDN compliance screening, tax tracking, and a complete
billing and invoicing platform. He leads AI implementation and adaptation at
Polygon. Today he's writing *The Freelance Playbook*
(a field guide to freelancing and consulting, at
[freelanceplaybook.co](https://freelanceplaybook.co)), builds ForTime, a
free workout timer app for CrossFit, HIIT, and functional fitness, under his
[Knurl Fitness](https://knurlfitness.com) brand, and runs
[Listomo](https://listomo.com), affordable email marketing software.

## Key Pages

- [About](https://donnfelker.com/about/): Bio, background, and books
- [Articles](https://donnfelker.com/articles/): 500+ posts on software engineering, freelancing, and self-direction
- [Podcast](https://donnfelker.com/podcast/): Building software products, financial freedom, health, and fitness
- [Projects](https://donnfelker.com/projects/): Current products (The Freelance Playbook, ForTime, The Contract, Thinky Face, Freelance Tactics, Listomo) plus the full project timeline back to 1997
- [Companies](https://donnfelker.com/companies/): Companies he's helped build (Google, Disney, American Express, Tinder, and more), with details on agilevent.com
- [Books](https://donnfelker.com/books/): Books and magazine writing: freelancing, Android development, and .NET
- [Contact](https://donnfelker.com/contact/): Get in touch via social media

## Optional

- [Substack](https://donnfelker.substack.com/): Long-form essays and product postmortems
- [RSS feed](https://donnfelker.com/feed/)
- [Newsletter](https://donnfelker.com/email/): One deep piece most weeks on thinking clearly, working for yourself, and staying valuable while AI rewrites the rules
- [Media kit](https://donnfelker.com/media/): Photos and assets for press and guest appearances