
Cathode: Screen Effects
20 live full-screen visuals
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Free
In-App Purchases
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About
Cathode turns your iPhone or iPad into a screen worth handing over.
Twenty full-screen effects, each one drawn live on the device at full frame rate. Nothing here is looping video and nothing is a static wallpaper — every pixel is computed while you watch.
WHAT IS IN IT
• Digital Rain — columns of glyphs falling through the dark. Choose the script:
Katakana, Japanese, Chinese, Hangul, Vietnamese, Latin, Cyrillic, Greek, hex or
binary. Let it fall as random characters, as good wishes written in that
language, or as anything you type yourself
• Code Editor — source typing itself out character by character, with line numbers and syntax colours, in C, Python, HTML, Java, SQL or JavaScript
• Terminal — a console mid-session: boot logs, hex dumps, network traces
• Breach — a wall of small monitors working a system open, with a progress bar counting up to the moment it gives
• Locator — a map acquiring a fix, accuracy rings closing in on a crosshair
• Radar, Spectrum, Oscilloscope — instruments with real graticules and phosphor afterglow
• Neural Grid, Automaton, Double Helix, Orbitals, Strange Attractor, Interference, Fractal — science that is actually being computed: Conway's Game of Life and Rule 110 run for real, the attractors integrate their own differential equations, the interference pattern is summed per pixel
• Starfield, Vortex, Plasma, Hyperspace, Glitch — pure spectacle
TWO TAPS TO FULL SCREEN
Pick an effect and it fills the screen edge to edge, with nothing on top of it and the display kept awake. Tap once and a small control bar fades in; leave it alone and it fades back out. Turn the device and the effect reflows with it.
MAKE IT YOURS
Every effect has speed, density, glow, eight colour palettes and several styles. Adjust them against a live preview, then save what you like as a named preset.
ENTIRELY OFFLINE
No account. No network requests of any kind. No analytics, no crash reporter, no third-party SDK. Cathode never asks for a single permission — not the camera, not the microphone, not location — because it never needs one.
FREE AND PAID
Digital Rain is free forever, at full quality, with every setting unlocked. No watermark, no time limit, no advertising.
Cathode Unlimited is a single one-time payment that unlocks the other nineteen effects and raises the saved-preset limit. It is not a subscription. It does not renew. It is shareable through Family Sharing.
A NOTE ON WHAT THIS IS
Everything on screen is generated by the app. The console text, network traces, radar contacts and progress bars are decorative fiction — nothing is a real system or a real connection, and none of it should be presented to anyone as though it were.
PHOTOSENSITIVITY
Some effects flicker or change brightness quickly. If you are sensitive to flashing imagery, use the Speed and Glow controls to slow and soften them, or do not use the app. Effects keep the display awake and can make the device warm; both are switches you control.
Terms of Use: https://csyzd.github.io/privacy/Cathode/terms.html
Privacy Policy: https://csyzd.github.io/privacy/Cathode/privacy.html
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What's New in Cathode
1.0.0
September 11, 2026
1
Subscriptions & In-App Purchases
$1.99
Cathode Unlimited
Unlock all twenty screen effects.





