7 free tools
Free tools for iOS developers
These pages collect the small, repeatable jobs that come up while building and shipping a mobile app: shaping a push payload, exporting icons, checking screen dimensions, estimating ad revenue and testing vibration. There is also a pair of study aids for algorithms. Everything opens in the browser, and none of the tools ask for an account or your signing keys.
- Push notification testerBuild and validate an APNs payload against the 4 KB limit.
Push Notification - TesterOpen - App icon generatorTurn one 1024 image into an Xcode AppIcon.appiconset ZIP.
Catalog - UIOpen - iPhone screen sizesPoints, pixels, scale and PPI for every iPhone in use.Catalog - UIOpen
- eCPM calculatorSolve for earnings, impressions or eCPM, plus CTR and ARPDAU.
AdEarnings ProOpen - Vibration testTest the vibration motor with preset and custom patterns.
Haptics ExplorerOpen - Sorting algorithm visualizerWatch six sorting algorithms step through the same data.
DSA MasterOpen - Data structures and algorithmsWhat each structure and algorithm is, and what it costs.DSA MasterOpen
About these tools
The push notification tester builds an Apple Push Notification service payload from the aps keys you choose, checks it against the APNs rules and the 4 KB size limit, and covers background pushes. It then gives you a ready curl command, an FCM equivalent and a Simulator command to copy. You do not paste any certificate or key into the page.
The app icon generator takes one square 1024 pixel image and produces an Xcode AppIcon.appiconset with its Contents.json, either the single 1024 size or every legacy size, plus optional Android icons, as a ZIP. It removes the alpha channel, which App Store Connect rejects on the marketing icon.
The iPhone screen sizes table lists points, CSS viewport, scale factor, native pixels and pixel density for the iPhones in use today, and shows a live reading of the screen you are using. The eCPM calculator solves for whichever of earnings, impressions and eCPM you leave blank, then adds CTR, earnings per click and ARPDAU if you enter clicks or daily users. It works with numbers from AdMob or any other network.
The vibration test plays short, long, SOS and custom patterns on Android phones. It also explains why iPhone browsers cannot vibrate and how to test iPhone haptics instead.
For interview practice or teaching, the sorting algorithm visualizer runs bubble, selection, insertion, merge, quick and heap sort on the same data, one comparison or swap at a time, with counters for the work each one does. The data structures and algorithms reference has one page per topic, with what it is and what the common operations cost.
Several of the tools pair with an app from the same developer, and each page links to it.
Questions
Do I need to upload my APNs key or certificate?
No. The push notification tester only builds and checks the JSON payload and prints the command to send it. You run that command on your own machine with your own credentials.
Which icon sizes does the app icon generator make?
It makes an Xcode AppIcon.appiconset with Contents.json, either the single 1024 by 1024 icon that current Xcode uses or every legacy iPhone and iPad size, and it can add Android launcher icons. Everything downloads as one ZIP.
Can a web page make an iPhone vibrate?
No. Safari on iPhone does not support the Vibration API, so the vibration test works on Android browsers only. The page explains how to check the Taptic Engine on an iPhone instead.