Sampled from 3 of JS Shell's App Store screenshots — background, accent and theme, measured by LaunchShots (not something Apple publishes).
#040404 bg
#272727
#FCD404 accent
#FFFFFF text
Reading the caption text from the screenshots in your browser…
JS Shell is a pocket-sized developer console that lets you write, run, and test web code (HTML, CSS, JavaScript) directly on iOS and macOS. No Xcode, no laptop, no remote server. Paste a page in, tap run, and it loads in a real WKWebView served from a local HTTP origin. A real secure-context origin on iOS, so modern web APIs — from WebRTC to Geolocation — behave the way they should. KEY FEATURES Local HTTP server. An in-process server bound to the loopback interface. Provides a real secure-context origin so modern Web APIs work out of the box. Not reachable from outside the device. JavaScript REPL. A full JavaScript runtime backed by JavaScriptCore. Type js to enter the REPL. console.log, fetch, setTimeout, setInterval, Promises, and async await are all available. Real Promises, real microtasks, real JSON parsing, real URL parsing. Geolocation support. Test navigator.geolocation o…
Every shipping app on the App Store has gone through the same decisions you're working through right now: which screenshot goes first, what caption sits over it, which device frame to show, what color the background should be. The 4 screenshots above are JS Shell's answers to those questions — they're public, they're real, and they made it through Apple's review.
What the numbers say: JS Shell runs a dark set with one background colour (#040404) carried across every screenshot — the listing reads as a single poster when the shots sit side by side in search results. The accent colour we picked up, #FCD404, is the one to reuse for badges, arrows and highlighted words if you borrow this look. Hit Use this style to open the editor with these exact colours and drop your own screenshot in.
Notice the first screenshot in particular. It's the one users see in search results and on the product page, and it's where most apps spend their best caption and tightest design. Look at the proportion of background to phone, where the text sits, what one thing the image is trying to communicate.
Want to see how other Developer Tools apps approach the same problem? Browse more Developer Tools apps in the showcase.
Open LaunchShots and design your App Store & Google Play screenshots — pick a device frame, drop captions, ship in minutes. Free, in your browser.
Open the screenshot editor →Closest background + accent colours among the listings we've analysed — useful when you want to see the same palette handled by a different team.