Synapse AI Keyboard Features — Built for Fast, Private Typing
A full AI assistant built directly into your Android keyboard. Works inside WhatsApp, Gmail, Instagram, Reddit, and every app you type in.
Synapse Keyboard is an Android keyboard that provides on-demand AI grammar correction, translation, tone rewriting, and custom prompts in any app where you type.
AI Prompts — The Core Feature
Write any instruction once — "Fix grammar", "Translate to Arabic", "Reply politely declining" — and save it. In any app: select your text, tap the Synapse icon, tap the prompt. The AI's answer replaces your text in a few seconds. Presets are included, and grammar, translation, and tone rewriting all work this way — they're prompts, so you control exactly what the AI does.
Grammar & Spelling Fix
Fix grammar, spelling, and sentence structure in any app — select your text, tap the Synapse icon, tap Fix Grammar. On-demand, not as-you-type. No need to copy-paste to a separate editor.
Learn more about AI Grammar Checker →
Custom AI Prompts
Save custom prompts for messages you send often. Write client pitches, response templates, or greeting sequences once, then run them from the Synapse panel in any app. You can save as many prompts as you want — no cap.
See how freelancers use this →
Text Shortcuts
Turn short triggers into full text instantly. Set up a shortcut like "omw" → "On my way!" or "addr" → your full address, and Synapse expands it the moment you hit space — in any app. It runs entirely on your device, works offline, and never spends AI credits, so your most-typed phrases are always one word away.
Privacy-First Input
No autocorrect cloud, no next-word prediction, no learning: Synapse doesn't build a profile of how you type, and normal typing never touches the network. AI runs only when you explicitly send selected text to a prompt; those inputs and outputs are stored in your account history. Nothing is ever saved from password or OTP fields.
Themes & Key Sounds
Two clean themes — Premium Black (OLED-friendly, default) and Premium White — plus 9 optional key-click sounds (including Typewriter, Crystal Ping, and Neon Zap), haptic feedback, and an adjustable keyboard height.
What Synapse Doesn't Do
No as-you-type grammar underlining — fixes are on-demand. No autocorrect, next-word prediction, swipe typing, or voice input. English keyboard layout only (AI can write and translate in other languages). Android only, installed via APK — Android shows its standard sideload warning. Google sign-in is required, and all AI features need internet; typing, text shortcuts, and clipboard work offline.
Compare with competitors → Best AI Keyboard 2026
Works in WhatsApp? Yes. See WhatsApp integration details →