Donny Wals Portfolio
Dutch iOS engineer, author and speaker whose deep dives into Swift Concurrency and Combine turned into standalone books — proof that a blog's best long-form posts can become a second product line.
What makes it work
A breakdown of the choices that make this portfolio stand out.
Books built directly from proven blog content
His books grew from the same long-form style already tested on the blog — validating the idea has an audience before charging for a refined version.
Topic timing aligned to genuinely new platform features
Writing the concurrency book while the feature was still new and unfamiliar filled a real, urgent knowledge gap.
A tight topic focus across blog, book and video
Swift Concurrency and Combine specifically, not "iOS" broadly, repeat across every format.
What Mobile Developers can take from this
Specific, actionable tips to apply to your own portfolio — no generic advice.
Write your best long-form explanations for free first — strong engagement is your signal a topic could become a paid book or workshop.
Publish your deepest content right as a technology is new and unfamiliar.
Pick 1-2 specific technical topics and repeat them across every format you publish in.
Build a ladder of content depth — free posts, a paid book, a live workshop — for the same expertise.
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