# 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 Platform, Enablement and Adoption 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. The full archive: technical posts publish here, essays are mirrored here from Substack - [Podcast](https://donnfelker.com/podcast/): Autonomous (autonomouspodcast.com), unfiltered conversations about building products and using AI as a tool; plus Fragmented, the Android developer podcast he co-hosted 2015 to 2022 - [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/): Weekly essays, published there first, plus product postmortems. Also the newsletter, and the only email list - [RSS feed](https://donnfelker.com/feed/) - [Newsletter](https://donnfelker.com/email/): Subscribe page for the weekly essays (one deep piece most weeks on thinking clearly, working for yourself, and staying valuable while AI rewrites the rules). The list itself lives on Substack - [Media kit](https://donnfelker.com/media/): Photos and assets for press and guest appearances