# Walsh Costigan, independent app developer > Walsh Costigan is an independent iOS, Android and web app developer with 10+ years of experience. He builds apps for creators and influencers (especially fitness creators and YouTubers), non-technical founders, startups and businesses, from idea to App Store launch. He also takes over, fixes and maintains existing apps, and helps them scale: paywall conversion, pricing, churn, onboarding, retention and App Store optimization (ASO). ## Key facts - Builds cross-platform apps with React Native and Expo, plus full-stack web with Ruby on Rails, React and Node.js. Uses Firebase, PostgreSQL, Stripe, RevenueCat and PostHog. - Has personally shipped 4 apps to the App Store and Google Play, with 1M+ total downloads. - Escape the Vape: co-founder and sole developer. The first quit-vaping app on iOS and Android, around 10K downloads a month, grown as a subscription business through pricing experiments, ASO and analytics. - Dry Quest: founder and sole developer. A freemium, RPG-styled app for mindful drinking with daily quests and an in-app economy (Expo, Firebase, Rive, RevenueCat). - Drip: a caffeine tracker with AI photo and voice logging, built in 3 days and live on the App Store. - Lexody: one of the first language-exchange platforms, on web, iOS and Android since 2014. - Spent 3 years as a senior developer at a startup. Works solo or alongside teams, and partners with professional designers. - Works with clients worldwide. Contact: https://walshcostigan.com/#contact - GitHub: https://github.com/gwalshington ## Services - Building an app from an idea or audience (MVP to launch) - iOS and Android apps (React Native / Expo) - Full-stack web apps - Launch and growth: ASO, paywalls, subscription pricing, churn reduction, analytics - Taking over, fixing and rescuing existing apps - Ongoing app maintenance: OS and SDK updates, dependency upgrades, bug fixes ## Articles: building an app for your audience - [Revenue Share and Equity App Deals for Creators: How They Work and When They Make Sense](https://walshcostigan.com/blog/app-development-revenue-share-for-creators): Can an influencer get an app built for a revenue share or equity instead of cash? How these deals are structured, what's fair, the red flags, and the questions to ask before signing. - [How to Launch an App to Your Audience: A Creator's Launch Playbook](https://walshcostigan.com/blog/launching-an-app-to-your-audience): A week-by-week launch plan for YouTubers and influencers releasing their own app. Waitlists, beta testers, launch-day velocity, offers, and what to do in the 30 days after. - [Custom App vs. White-Label Fitness App Platforms: Which Should Creators Choose?](https://walshcostigan.com/blog/custom-app-vs-white-label-fitness-app-platforms): An honest comparison of white-label fitness app builders and custom-built apps for creators and trainers, covering cost, revenue share, ownership, App Store risk and when to switch. - [How Long Does It Take to Build an App? Realistic Timelines for 2026](https://walshcostigan.com/blog/how-long-does-it-take-to-build-an-app): Honest app development timelines from a developer who has shipped apps in 3 days and in 3 months. What a typical MVP takes, what slows builds down, and how to launch faster. - [Workout App MVP: The Features You Need at Launch (and What to Cut)](https://walshcostigan.com/blog/workout-app-mvp-features): A developer's feature-by-feature guide to scoping a fitness or workout app MVP, covering what to build for launch, what to save for v2, and why less ships faster and earns more. - [How Much Does It Cost to Build a Fitness App in 2026?](https://walshcostigan.com/blog/how-much-does-it-cost-to-build-a-fitness-app): Realistic 2026 costs for building a workout or fitness app, from white-label platforms to custom iOS and Android builds, plus the ongoing costs nobody quotes you. - [Should Creators Build an App? When It Makes Sense (and When Patreon, Skool or Kajabi Is Better)](https://walshcostigan.com/blog/should-creators-build-an-app): An honest framework for YouTubers and influencers deciding whether to build their own app or stick with Patreon, Skool, Kajabi or a community platform. - [How to Build a Fitness App as an Influencer (Step-by-Step, 2026)](https://walshcostigan.com/blog/how-to-build-a-fitness-app-as-an-influencer): A developer's step-by-step guide for fitness creators and YouTubers who want their own workout app. Validation, features, cost, tech, launch and the subscription model that makes it work. ## Articles: building a new app - [How Much Does It Cost to Build an App in 2026? A Developer's Honest Breakdown](https://walshcostigan.com/blog/how-much-does-it-cost-to-build-an-app): Realistic 2026 app development costs by app type and by who builds it (freelancer, independent developer, agency), plus the ongoing costs, the hidden costs, and how to get an accurate quote. - [How to Turn an App Idea Into a Real App (A Guide for Non-Technical Founders)](https://walshcostigan.com/blog/how-to-turn-an-app-idea-into-a-real-app): A step-by-step path from app idea to App Store launch for non-technical founders and business owners, covering validation, scoping, hiring, building, launching, and protecting yourself along the way. - [MVP App Development: How to Scope, Build and Launch a Minimum Viable Product](https://walshcostigan.com/blog/mvp-app-development-guide): A practical guide to MVP app development, covering what an MVP should and shouldn't include, how to scope features, a realistic timeline, the tech choices that keep you flexible, and what to measure after launch. - [Native vs. Cross-Platform App Development: React Native, Flutter or Swift/Kotlin?](https://walshcostigan.com/blog/native-vs-cross-platform-app-development): How to choose between native iOS/Android development and cross-platform frameworks like React Native and Flutter, covering cost, performance, hiring, maintenance and when each one is the right call. ## Articles: hiring an app developer - [The Best Tech Stack for Creator & Subscription Apps in 2026 (Expo, RevenueCat, Firebase)](https://walshcostigan.com/blog/best-tech-stack-for-creator-apps): The tech stack I use to build and scale subscription apps for creators, covering React Native and Expo, RevenueCat, Firebase or Supabase, analytics and video hosting, and why each choice keeps costs down and keeps you in control. - [Freelance App Developer vs. Dev Shop vs. Agency: Which Should You Hire?](https://walshcostigan.com/blog/freelance-app-developer-vs-dev-shop-vs-agency): An honest comparison of hiring an independent app developer, a small dev shop or a full agency, covering cost, speed, quality, communication and risk, with a recommendation for each situation. - [How to Hire an App Developer: 12 Questions to Ask (and the Red Flags)](https://walshcostigan.com/blog/how-to-hire-an-app-developer): A practical guide for creators and founders hiring an app developer, covering where to look, what to ask, how to check a portfolio, how pricing works, and the red flags that predict a failed project. ## Articles: fixing & maintaining an app - [How to Find a Developer to Fix Your App (and What to Send Them First)](https://walshcostigan.com/blog/find-a-developer-to-fix-my-app): Need someone to fix bugs, crashes or broken features in an existing app? How to find the right developer, what information to send, what a fix engagement looks like, and how to avoid paying twice. - [App Maintenance: What It Includes and How Much It Costs Per Year](https://walshcostigan.com/blog/app-maintenance-cost): What app maintenance actually involves (OS updates, store SDK deadlines, dependency upgrades, bug fixes, monitoring), what it costs per year, and how to choose between hourly, retainer and in-house maintenance. - [Updating an Outdated App: Store SDK Deadlines, React Native/Expo Upgrades and What to Do First](https://walshcostigan.com/blog/updating-an-outdated-app): Your app hasn't been updated in a while and now it won't build, can't be submitted, or is falling behind store requirements. How to bring an outdated iOS or Android app up to date safely. - [How to Fix an App That Keeps Crashing (iOS & Android)](https://walshcostigan.com/blog/how-to-fix-an-app-that-keeps-crashing): A developer's process for finding and fixing app crashes and freezes, covering crash reporting, prioritising by impact, common causes in React Native and native apps, Android vitals thresholds, and preventing regressions. - [App Rescue: What to Do When Your Developer Leaves (or Your App Is Falling Apart)](https://walshcostigan.com/blog/app-rescue-taking-over-an-existing-app): A step-by-step guide to taking over an existing app after a developer or agency leaves, covering how to secure your accounts, audit the code, stabilise the app and decide between fixing and rebuilding. ## Articles: scaling an existing app - [Common App Store Rejection Reasons (and How to Avoid Them)](https://walshcostigan.com/blog/app-store-rejection-reasons): The App Store review guidelines that most often reject creator, fitness and subscription apps (in-app purchase, subscription disclosure, minimum functionality, template apps, account deletion, privacy), and how to pass review the first time. - [App Onboarding and Retention: How to Get Users to Day 30](https://walshcostigan.com/blog/app-onboarding-and-retention): How to design onboarding, habit loops and re-engagement that keep users coming back to a fitness or habit app, with lessons from building gamified apps like Dry Quest and Escape the Vape. - [Web Checkout vs. In-App Purchase: Should Your App Sell Subscriptions Through Stripe?](https://walshcostigan.com/blog/web-checkout-vs-in-app-purchase): Pros, cons and current rules for selling app subscriptions on the web through Stripe vs. Apple and Google in-app purchase, including store fees, conversion trade-offs and a hybrid setup for creator apps. - [App Store Optimization (ASO) for Creator Apps: Get Found Beyond Your Audience](https://walshcostigan.com/blog/app-store-optimization-for-creator-apps): A practical ASO guide for creator, fitness and subscription apps, covering keyword research, titles and subtitles, screenshots that convert, ratings, in-app events, custom product pages and A/B tests on iOS and Google Play. - [How to Price a Subscription App: Monthly vs. Annual vs. Lifetime for Creator Apps](https://walshcostigan.com/blog/subscription-pricing-for-creator-apps): How to set subscription prices for a creator or fitness app, covering price points, monthly vs. annual vs. lifetime plans, free trials, regional pricing, and how to test prices without hurting revenue. - [How to Reduce Churn in a Subscription App (Fitness & Habit Apps Edition)](https://walshcostigan.com/blog/how-to-reduce-subscription-app-churn): Why subscribers cancel fitness and habit apps, and the product, pricing and lifecycle tactics that reduce both voluntary and involuntary churn, from a developer who runs subscription apps. - [How to Improve Paywall Conversion in a Subscription App (A Developer's Playbook)](https://walshcostigan.com/blog/how-to-improve-paywall-conversion): Practical, tested ways to raise paywall conversion and trial-to-paid rates in iOS and Android subscription apps, covering placement, design, trials, pricing display, onboarding and experiments. - [Your App's Growth Has Plateaued: A 7-Step Growth Audit Checklist](https://walshcostigan.com/blog/growth-audit-for-a-plateaued-app): A step-by-step audit for subscription apps whose downloads or revenue have stalled, covering acquisition, store page conversion, onboarding, paywall, retention, churn and pricing, and how to find the leak worth fixing first.