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Cornelius Mark @corneliusmark

Innovative macOS/iOS developer building apps that shine. Need a bold app solution? DM me let’s create! ⬇️

Joined December 2010
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Cornelius Mark
@corneliusmark
5 Jun 2025
Hello, I craft macOS and iOS apps that scale, perform, and delight users. From modular architectures to bug-free code, I deliver solutions that grow with your vision. Let’s chat about your next project! Here’s what clients say about my work: ⭐⭐⭐⭐⭐ "Mark is a guru in everything MacOS and app store related. A pleasure to work with!" – Safari extension for a search engine. ⭐⭐⭐⭐⭐ "Great communication, fluent English, quick action, knows exactly what he's doing." – macOS taskbar app. ⭐⭐⭐⭐⭐ "Mark was great to work with and is an expert at his craft." – WidgetKit widgets for Big Sur. DM me let's build something amazing! Best, Mark
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Three pricing experiments I ran on real client iOS apps last quarter. One increased revenue by 4.2 times. The winning model gave users a cheap way in plus a yearly option for more value. Most solo founders pick the wrong pricing and stay stuck with low earnings. This one change can help you earn more from your app.
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After 47 client audits I noticed this pattern. Many indie app makers hide their client results because the work is not perfect yet. This small habit creates a trust leak. Your potential clients never see proof of your skill, so they do not reach out. Start sharing your real results. Even imperfect ones build authority and bring leads.
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Monthly subscriptions are dead for new apps in 2026. Users have grown tired of recurring charges before they even trust your app. The hybrid model that works: offer one clear upfront payment for complete access. Add an optional yearly plan for updates and new features. This simple change increased revenue more than four times in tested apps. It gives users control and removes hesitation.
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If you only have 20 minutes this week, use it for this.
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Test it for one week and check your revenue and retention numbers.
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Reply with your results. What worked for you?
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Three client apps proved my three-question validation test works. Revenue went from under 300 dollars a month to over 5000 dollars on average. One founder still reaches out six months later. Solo iOS founders who struggle with user acquisition and monetization can use this test to pick better ideas early. Comment VALIDATION and I will send you the questions.
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Apps stuck at one-star ratings often share one hidden problem. They force users to create an account before trying anything. Your most valuable power users just want to test the app first. When you block that, they leave angry reviews and never return. We see this in almost every low-rated audit. Change this one step and watch your retention and ratings improve. What does your launch flow look like right now?
Slide 1/4: Here is what happens when your iOS app forces new users to create an account immediately.

ALT Slide 1/4: Here is what happens when your iOS app forces new users to create an account immediately.

Slide 2/4: The best users who could pay and stay only want to try the app first.

ALT Slide 2/4: The best users who could pay and stay only want to try the app first.

Slide 3/4: Ignoring this leads to frustration, one-star ratings, and users who never return.

ALT Slide 3/4: Ignoring this leads to frustration, one-star ratings, and users who never return.

Slide 4/4: In our audits this simple change lifts ratings and keeps more users. What is your current onboarding like? Comment below.

ALT Slide 4/4: In our audits this simple change lifts ratings and keeps more users. What is your current onboarding like? Comment below.
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Indie iOS makers keep failing because they skip the basics. Do these four things in exact order. Run the three question validation test first. Then build only the needed parts. Create clear screenshots that show value immediately. Finally set pricing that works. Skip any step and you stay in the group that never gets real users or revenue. Comment VALIDATION if you want the test.
Tired of building iOS apps that get no downloads? Here are the four steps that actually work.

ALT Tired of building iOS apps that get no downloads? Here are the four steps that actually work.

Start with the three question test. It takes minutes and saves months.

ALT Start with the three question test. It takes minutes and saves months.

Focus only on confirmed needs. This improves user acquisition fast.

ALT Focus only on confirmed needs. This improves user acquisition fast.

Stop manual screenshot work. Strong first images boost ratings and installs.

ALT Stop manual screenshot work. Strong first images boost ratings and installs.
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Popular advice on app ratings is backwards. Here is what actually works. We took a client from 1.2 stars to 4.7 stars in 11 days with four changes. We fixed the main complaints, simplified onboarding, showed value immediately, and added fast support. Solo founders and small teams: low ratings hurt your downloads and revenue. These steps can change that. Comment RATINGS and I will send you the details.
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Your SwiftUI app is slower than it needs to be. Pre-ARC memory management errors are still active in many modern apps. They cause leaks that hurt speed, battery, and user retention. Check for strong reference cycles in your closures and missing weak self. Use Instruments to find them. Fix these issues and your app will feel faster. This helps with ratings and keeps users longer. What performance problem are you facing right now?
Your app runs slow for users. Many times the cause is old memory management issues that still affect SwiftUI apps.

ALT Your app runs slow for users. Many times the cause is old memory management issues that still affect SwiftUI apps.

Look for strong reference cycles. They happen when closures or delegates keep objects in memory longer than needed.

ALT Look for strong reference cycles. They happen when closures or delegates keep objects in memory longer than needed.

Check for notifications and observers you forgot to remove. These silently hurt performance and battery life.

ALT Check for notifications and observers you forgot to remove. These silently hurt performance and battery life.

Open Instruments, profile your app, and use weak references where needed. What memory issue have you fixed recently? Comment below.

ALT Open Instruments, profile your app, and use weak references where needed. What memory issue have you fixed recently? Comment below.
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Indie iOS makers, your feed can bring real clients. Share one client success story each month. Ask for permission. Document the actual gains in users or money. Post the facts. This simple step turns quiet posts into a steady lead source. Who wants the full steps?
Indie app makers often struggle to get new clients. Here is how one simple habit changes that.

ALT Indie app makers often struggle to get new clients. Here is how one simple habit changes that.

Always start with permission. Respect your clients and be transparent.

ALT Always start with permission. Respect your clients and be transparent.

Focus on real numbers that matter: more downloads, better retention, higher revenue.

ALT Focus on real numbers that matter: more downloads, better retention, higher revenue.

Do this every month and your feed stops being a portfolio. It becomes a source of new leads. Ready to try? DM me.

ALT Do this every month and your feed stops being a portfolio. It becomes a source of new leads. Ready to try? DM me.
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Long multi step forms on mobile in 2026 are not professional. They are user abuse. Your retention graph proves it. Users start the form then quit. That early drop hurts your daily active users and ratings. Shorten the forms. Ask the minimum first. Let people use your app quickly. Test it in your next update and watch retention rise.
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If you only have 20 minutes this week, here is what to do. Launch a 4.99 one-time purchase in week two of the user journey. Show this message after they use the core feature twice: Unlock full access for 4.99. One payment. Keep the app forever. It works well for indie iOS apps and does not scare people away. Who wants to try it?
Many solo founders waste time on big launches. Start small instead.

ALT Many solo founders waste time on big launches. Start small instead.

Week two is the perfect moment. Users know your app value by then.

ALT Week two is the perfect moment. Users know your app value by then.

This exact message converts well and does not scare users away.

ALT This exact message converts well and does not scare users away.

Try it this week. Comment "4.99" if you want the full timing details.

ALT Try it this week. Comment "4.99" if you want the full timing details.
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If you only have 20 minutes this week, here is what to do. Launch a 4.99 one-time purchase in week two of the user journey. Show this message after they use the core feature twice: Unlock full access for 4.99. One payment. Keep the app forever. It works well for indie iOS apps and does not scare people away. Who wants to try it?
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Three client apps proved my 3-question validation test works. Revenue went from under 300 dollars a month to over 5000 dollars on average. One founder still reaches out six months later. If you are an indie iOS maker stuck with low downloads or revenue this test helps you pick winning ideas fast. Comment VALIDATION and I will send the questions.
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One small micro-interaction turned a client's budget app from 2.1 star reviews to 4.8 stars in 9 days. This is the part indie app makers never see until we fix it together. If your ratings are stuck low and users leave fast, the solution is often tiny but powerful. Comment ratings and I will show you what worked.
Low ratings killing your app? This is the part most solo founders miss.

ALT Low ratings killing your app? This is the part most solo founders miss.

One small interaction fixed it for a client budget app.

ALT One small interaction fixed it for a client budget app.

From 2.1 to 4.8 stars in only 9 days.

ALT From 2.1 to 4.8 stars in only 9 days.

Comment ratings and I will share exactly what changed. It works for retention too.

ALT Comment ratings and I will share exactly what changed. It works for retention too.
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