Building an Expense Tracker in Public, One Threads Post at a Time
Marlon Joel Pitters is building Costify — an iOS expense tracker — entirely solo, narrating every step from beta test to bug fix on Threads. It's a small app so far, but a clear example of what indie, build-in-public development actually looks like day to day.
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Title: Building an Expense Tracker in Public, One Threads Post at a Time
Slug: marlon-pitters-costify-build-in-public
Summary: Marlon Joel Pitters is building Costify — an iOS expense tracker — entirely solo, narrating every step from beta test to bug fix on Threads. It's a small app so far, but a clear example of what indie, build-in-public development actually looks like day to day.
Hero image: https://is1-ssl.mzstatic.com/image/thumb/PurpleSource221/v4/1f/c4/8d/1fc48d9b-8dd4-20ef-a032-a6b1b5b4c07f/firstpage.png/471x1024.jpeg (Official Costify App Store screenshot — budget overview screen. Sourced from Apple's App Store CDN; screenshots and app description are the property of the app developer.)
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Building an Expense Tracker in Public, One Threads Post at a Time
Most startup stories get written after the fact — funding secured, traction proven, narrative smoothed over. Marlon Joel Pitters' story with Costify is the opposite: it's being written in near real time, one Threads post at a time, warts included.
Costify is an iOS expense tracker aimed at a specific kind of user — not just someone logging personal spending, but people who split costs with others: travel groups, shared flats, couples managing a household budget together. Pitters is building it alone, handling design, development, support, and marketing himself, and has chosen to do almost all of it publicly, mostly on Threads (@marlon.pitters).
From beta to launch, out loud
The public trail starts in September 2025, when Pitters opened a TestFlight beta and posted about it directly to his following: "The public testing phase of Costify starts today. I look forward to your feedback and to developing the app further together with you." That framing — feedback and development as a joint activity with his audience, not something happening behind a closed door — has stayed consistent since.
By late January 2026, Costify was live on the App Store. Pitters marked it plainly: "Costify is officially live on the App Store. Months of work, learning, and iteration went into this. Grateful for everyone who supported me along the way. This is just the beginning." By early March, he was , thanking his following by name for the support.
