/about
Derek Castelli
Des Moines, Iowa metro
Self-taught designer designing brands and making websites for non-profits and startups since 2010. Oh and always working on a side project or three.
Right now
Highlights
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The Mac Desk
First Mac Apps, Built with AI
It started when another Mac app crashed on me—I built Binky and Dinky with Claude and Cursor, my first shipped Mac apps. Both within weeks would get 200+ stars on GitHub.
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Church & Code
Faith-Tech Side Projects
Harvous is the Bible app I dogfood—threads, scripture, cross-refs, and group sharing. 3,685+ commits, early access at harvous.com. Here’s My Church indexed 256k+ churches on day one.
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The Client Desk
Marketing Sites That Scale
Claimable through Kem Design—marketing and engineering praised the Mast build for easy new pages. For Scenery I did brand, logo, and site before Adobe acquired them.
Derek helped me revamp Scenery's brand, logo, and website in the first two months of my tenure and was a crucial, fun partner to work with throughout the process. Derek had a well defined process, integrated into the team well, and came up with creative approaches when they were most needed — at both the start and finish of the project. Thank you Derek!
Barrett Johnson
Former Head of Marketing at Scenery
Barrett was Derek's client · Nov 2023
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The Builder’s Journal
Learning by Doing
Apple Retail, then design lead at a large church, then indie full-time in 2020. Since then: Kem, clients, my own apps, open source, and family—still chasing rectangles that matter.
All projects28
Total side projects since 2008
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The First Client
A $100 Logo for Chris Ducker
The year was 2010. I was still in college playing in Sketch. Business man across the pond, Chris Ducker, would pay me $100 for a logo he still uses today (slightly revised).
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Iowa State Daily
Name in the Paper
I was a columnist for the Iowa State Daily. I wrote about Apple, social media, and campus life. It started the habit of publishing in public—before design blogs, clients, or my own site.
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The Public Feed
Posts That Landed
I write about dogfooding AI, faith apps that wow, and making rectangles. A SimCity post hit 883 likes and 30k+ views. Honest shipping and reflection is what lands.
You’re only given a little spark of madness.
You mustn’t lose it.
Skills
- Webflow & website design
- UI/UX thinking
- Brand & logo design
- Front-end development
- Visual design
- Prompt communication
- Customer support
- Writing in public
- Actively using AI tools
- Faith-tech product design
Experience
Current
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Jun 2020 — Present
Testament Made LLC
Freelance web designer partnering with clients and teams to make websites in Webflow, and making apps on the side.
testamentmade.com -
May 2024 — Present
Kem Design Co.
Webflow Expert assisting the team when it comes to making websites.
kemdesign.co
Past experience
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Jan 2025 — May 2026
Jamm Designs
Senior Web Designer (Freelance), designing websites and developing them in Webflow one update at a time.
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Jun 2024 — Sep 2025
Apollos
Partnered with the Apollos web team to design and develop Webflow websites for churches.
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Oct 2022 — Sep 2024
One Branding
Web designer and Webflow developer working with various clients from edutech to video gaming.
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Oct 2018 — Jun 2020
Eternity Church
Created and oversaw all creative elements of the church from graphics to merch to production.
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Aug 2012 — Oct 2018
Apple Retail
A mentor and leader in sales connecting with customers to truly get the Apple products they need.
Education
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Aug 2007 — May 2014
Iowa State University
Obtained a Bachelor of Arts in Communication Studies with supplementary time in Advertising and the College of Design.
Articles at Iowa State Daily