Lennart Brandt

expo.devFrom idea to income: How to build seamless subscriptions with Expo and RevenueCatLearn how Roamwise uses Expo and RevenueCat to implement seamless subscriptions—with custom hooks, smart paywall design, and real-world code.

🌍 Traveling often? Counting days abroad for visa or tax rules stressed me out—especially with frequent visits to the UK. That's why I built @roamwise.app (a react-native expo app), a privacy-first travel compliance tracker for iOS. Here's the story 🧵

Lennart Brandt reposted

Expo

@expo.dev

10 July 2025

✨ 3 hooks. 1 paywall. No mess. Learn how @brandtnewlabs.com built seamless subscriptions into his Expo app with @revenuecat.com using: • usePurchasesInitialize • usePurchasesMonitor • usePurchases Plus fantastic design tips: expo.dev/blog/how-to-...

certification-ads.apple.comI'm certified with Apple Ads and ready to drive campaign results on the App Store.Check out the certificate that confirms my successful completion of Apple Ads Certification.

13 May 2025

Refreshed my ASA knowledge with the official Apple Ads Certificate this morning! It took me 2 hours from start to finish 🥳 I'm now officially Apple Ads certified. Time to start my first campaign! certification-ads.apple.com/certificate...

github.comGitHub - RevenueCat/react-native-purchases: React Native in-app purchases and subscriptions made easy. Support for iOS and Android.React Native in-app purchases and subscriptions made easy. Support for iOS and Android. - RevenueCat/react-native-purchases

25 Apr 2025

Just realised the official react-native-purchases package by @revenuecat.com has only ~900⭐️… that’s 2,100 fewer than react-native-iap. Especially for @expo.dev apps, RevenueCat is the de facto standard for in-app purchases. Give it some love! ⭐️👇 github.com/RevenueCat/...

24 Apr 2025

I'm in love with @expo.dev, @swmansio.com's Reanimated, and gorhom's Bottom Sheet ❤️

23 Apr 2025

Normally I’m all for keeping things simple — no unnecessary UI or animations. But I’m a big fan of the Joi app and just had to recreate how the buttons animate when the bottom sheet changes position. Fun fact: @roamwise.app’s design is heavily inspired by Joi and Flighty ✨

22 Apr 2025

Spent one weekend building a custom animation system on top of @swmansion.com’s Reanimated and @expo.dev router. Every animation in my apps now feels on-brand — and I can animate anything in seconds.

22 Apr 2025

Here’s a look at my CardSheet in action: It uses expo-router’s transparent modal with animation: none — the animation is fully handled inside the sheet. Thinking about open-sourcing it… should I? 👀

@wutangforchildren.bsky.social

21 Apr 2025

Recording your work to share it? Great way to catch bugs 🐛 Just spotted some unnecessary re-renders in the Roamwise calendar while filming a demo 😅 #reactnative #expo #indiedev

Lennart Brandt reposted

WuTangIsForTheChildren

18 Apr 2025

London bus stop near Amazon HQ 🔥

Lennart Brandt reposted

18 Apr 2025

I’ve shared this animation before — but now it’s finally dialed in. ✨ Snappy pop-in scale on the buttons ⚡️ Fast spring for the progress bar 🌈 Interpolated colors on the progress dots Built using @expo.dev & @swmansion.com’s Reanimated. Code snippets + a gist for the progressDots below 👇

I’ll be attending @appjs.co in May! 🥳 Excited to meet fellow React Native & Expo devs IRL, chat about apps, animations, and everything in-between. Who else is going? Let’s connect! 👋 #AppJSConf #ReactNative #Expo #IndieDev

17 Apr 2025

Did you know ~60% of users decide whether to subscribe during onboarding? 🚨 That’s exactly why I placed Roamwise’s paywall at the end of onboarding. It instantly reconstructs your travel history from your photo library. Feels like magic 🧙‍♂️ #indiedev #buildinpublic #reactnative

Schengen rules are confusing. Roamwise isn’t ✨ I just launched SchengenPro — a new feature that gives travellers a clear, visual overview of their 180-day Schengen timeline. Here’s what it does and why I built it 🧵 #indiedev #reactnative #expo

I’m an EU citizen 🇪🇺, so I don’t deal with Schengen limits myself — but I’ve seen how confusing and stressful it is for non-EU travelers. So I set out to build the clearest, most intuitive solution out there. More visual. More useful. More… brandtnew. ✨

apps.apple.com‎Roamwise: Country Tax Tracker‎KNOW YOUR DAYS. STAY COMPLIANT. Roamwise helps you track how many days you’ve spent in each country — so you can stay on top of visa rules, tax residency limits, and travel planning with total peace of mind. WHY ROAMWISE? Designed for digital nomads, remote workers, frequent flyers, and expats, Ro…

Check out the new SchengenPro feature in Roamwise: apps.apple.com/app/id67436... No spreadsheets. No stress. Just clear rules — finally made visual.

Why this feature? During #ASO research, I found that “Schengen” has surprisingly high search demand — and very few good apps solving the problem. So I built a feature that makes sense in one glance — no spreadsheet brain freeze required.

If users love it, I’ll expand it: ✅ Trip planner → Simulate future travel to see if you’ll stay compliant before booking. ✅ Even smarter alerts & edge-case handling (e.g. dual passports, visa overlap)

That’s why I built SchengenPro inside Roamwise — a privacy-first travel compliance app. It gives you instant clarity on: ✅ How many Schengen days you’ve got left ✅ When you need to leave ✅ Which past dates count against your limit

The interface is designed for clarity: 🟩 Status tile — tells you if you’re compliant, close to the limit, or over it 🗓️ Recommended action — based on your situation 📊 180-day timeline graph — shows days spent: In Schengen, Outside Schengen, No data 🔜 Upcoming day releases — when your days reset

Most travellers can spend 90 days within any 180-day period in the Schengen Area. But calculating that manually? An absolute nightmare💀 You either rely on spreadsheets… Or clunky tools that feel more complex than the rules themselves.

15 Apr 2025

The one thing I’ve learned about App Store screenshots: They’re not just for looks—they’re your fastest pitch. With Roamwise, I made sure every screenshot instantly answers: “Why should I care?” Users don’t want features. They want instant clarity.

14 Apr 2025

Learned the hard way: Always test on a real device as early as possible ‼️ Simulator felt smooth—but on my actual phone, haptics hit different, and Roamwise’s photo analysis slowed way down with my full media library. Nothing beats real-world testing #reactnative #buildinpublic

12 Apr 2025

Turning 35 today! 🥳 Feeling great—healthier, happier, and more productive than ever. Freelancing with React Native @expo.dev wasn’t the plan, but it’s turned out to be a pretty good path to freedom.

11 Apr 2025

Clean routes, easy modals, and zero headaches ✨ @expo.dev router is such a joy to work with.

tryastro.appAstro: App Store Optimization Tool for iOS developersAstro helps you improve the visibility of your app and grow your revenue. Track keywords, check the popularity and difficulty of each keyword, and get suggestions on the best keywords to add.

1/ Using ChatGPT to optimise keywords for ASO? You’re leaving money on the table!!! 💸 It sounds smart. But in reality, ChatGPT completely ignores core ASO rules — and can seriously tank your keyword performance 🤡 A quick breakdown 🧵

8/ Want to DIY your keyword research like a pro? Here’s what I recommend: 🔍 Learn the App Store keyword rules 🧠 Use tryastro.app for idea generation 🧹 Manually clean and compress the final list 💯 Use every character wisely

9/ Hope this saved you some time, headaches, and keyword potential. If you’re building apps solo and care about visibility, ASO isn’t optional. It’s leverage. Follow for more indie dev + app growth lessons. And maybe ❤️ + RT if this was helpful 🙏

6/ Here’s how a human (me, after 5 hours of research and testing 😅) cleaned it up: ✅ country,day,track,log,trip,timer,journal,travel,map,visa,tax,stay → No fluff → 100% efficient → Keyword-rich → App Store compliant

7/ Bottom line: ChatGPT is great at suggesting keyword ideas. But DO NOT trust it to structure your final ASO keyword set. It will break the rules, waste your slots, and hurt your ranking.

4/ Here are a few ASO rules that ChatGPT regularly messes up: 🚫 No spaces in keyword field → use country,day,tracker not country day tracker 🚫 No plural/singular duplicates → use day, not days AND day 🚫 No word stem repeats → track OR tracker, not both 🚫 No duplicate keywords from Name/Subtitles

5/ Example: I asked ChatGPT to optimize for the term “country day tracker” Here’s what it gave me: country day tracker, travel logs, day counter, days tracked 👎 Spaces 👎 Duplicates 👎 Wasted characters 👎 Terms already used in my subtitle

2/ Let’s talk Apple App Store keywords. You’ve got 3 places that influence search visibility: ✅ App Name ✅ Subtitle ✅ Keyword field (hidden, 100 characters max) Get this wrong, and you’ll never rank.

3/ Most people assume ChatGPT can generate high-quality keywords for you. Spoiler: It can’t. 😬 It breaks the most basic ASO rules. And when you call it out? It gaslights you. “You probably meant to write it that way.” 😮‍💨

First subscribers after yesterday’s launch—already going strong at $10 MRR! 😁 Most heartwarming moment? ❤️ My mum becoming the very first Roamwise customer, tracking her & dad's nomad adventure across Europe. Indie dev milestone unlocked! ✅ #indiedev #buildinpublic

Working on the sleekest Schengen tool you’ve ever seen. Schengen rules are a mess — but this app makes them make sense at a glance. Coming to Roamwise tomorrow. #reactnative #ux #indiedev

Skipped Figma 🚨 Went straight from wireframe to real UI — all in code with Expo & NativeWind Designing in code feels more honest. Faster feedback, fewer steps, and everything clicks better. @roamwise.app is built this way from day one.

Got a bug report this morning about a broken subscription check in @roamwise.app. Talked to the user, found the issue, fixed it—and pushed the update to production within an hour. 🍎 No App Store review needed. 🪄 Just eas update --branch production 🥳 Thanks @expo.dev #ReactNative #IndieDev

Gonna frame this 🖼️ #reactnative @expo.dev

7/ I'm happy to have finally released Roamwise for iOS this week! It's been a tough few days making Apple happy (the good old reviews). But hey, it's now live on the App Store! Check it out and let me know what you think 🙏 apps.apple.com/app/id67436...

8/ Over the next weeks, I'll share more insights on design, development, ASO, marketing, and the realities of being a solopreneur juggling multiple roles 👀

5/ Admittedly, I spent way too much time perfecting the user experience. I even built my own animation system based on Reanimated—which I'll be using for future apps, too (right? 😅)

6/ Roamwise combines three simple, privacy-first methods: 📸 Photos Analysis (timestamps & GPS data) 📍 GPS Check-ins (daily logging) ✍️ Manual Logging (easy adjustments)

3/ As a frequent traveler myself, I needed a tool that simplified compliance tracking—especially spending significant time between Germany and the UK. So, I decided to build Roamwise myself.

4/ After selling my previous app, WeBurn, I wanted to put everything I'd learned into practice: from UX excellence to technical reliability. Roamwise was the perfect small-but-polished project.

2/ I saw an Instagram ad from a competitor promoting a travel compliance app. The idea seemed great, but I knew the UX could be WAY better. Plus, if someone was advertising, there had to be a real need, right? I went from "wireframes" on my iPad directly into code 👇

Lennart Brandt reposted

Callstack

@callstack.com

8 Apr 2025

How do you actually improve JS performance in React Native? Join us for a live walkthrough & Q&A of our Optimization Guide ➡️ streamyard.com/watch/VW8Ufy... 🟣 What’s hurting your FPS 🟣 Real profiling techniques 🟣 How to find memory leaks 🎙️ Hosted by @grabbou.com & @chmal.it 📅 Apr 15, 5pm CET

docs.expo.devEnvironment variables in EASLearn how to use and manage environment variables in EAS with examples.

4 Apr 2025

Can someone from the @expo.dev team release a short guide on how to properly manage .env variables for all things @sentry.io, @revenuecat.com, etc? With examples on 1 – How to make things run locally in DEV 2 – How to make builds work for PROD This "guide" 👇 is ... 😵‍💫 docs.expo.dev/eas/environm...