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WhatsApp, Gmail, Reddit, Upwork — wherever you type, select your text, tap the Synapse icon, and get AI help in seconds. No copy-pasting to ChatGPT. No app switching. Just pick your prompt and get the answer.
Works in any app
Synapse Keyboard is an Android keyboard with on-demand AI writing tools. Select text in an app, choose a grammar, translation, tone, or custom prompt, and Synapse returns a replacement without moving your draft to a separate editor. Normal typing remains on your device; only text you deliberately send to an AI prompt is processed. Synapse works wherever Android accepts keyboard input, including WhatsApp, Gmail, Instagram, and work chat apps. It is installed from an APK on Android 8.0 or later, includes 20,000 free credits to try its tools, and uses pay-as-you-go top-ups instead of a monthly subscription.
Grammar, translation, writing, coding — ask the AI whatever you want and get the answer directly in your keyboard.
Track remaining energy, daily usage, and prompts in real-time — synced instantly between mobile app and web.
Create, edit, and manage personal AI prompts from any device. Changes sync instantly to the keyboard.
Redeem Gumroad license keys to instantly credit energy to your account. No delay, no friction.
Highlight any text and tap the AI button to rewrite, improve grammar, change tone, or translate — right inside any app.
Two clean themes — Premium Black and Premium White — plus adjustable keyboard height, 9 optional key sounds, and haptic feedback.
Set a short trigger like "omw" and expand it to full text instantly as you type. Works offline in any app — no AI, no credits used.
Pay with USDT via Cryptomus. Get 30% more energy credits when you pay with crypto.
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Reply to any chat without leaving the conversation.
Pick a Prompt
Generating Reply
Instant Answer
Other keyboards give you grammar check. Synapse gives you a full AI assistant. Ask it to write emails, translate conversations, generate code, draft proposals — whatever you need, right where you type.
Most keyboards give you grammar check. Synapse gives you a full AI assistant — ask it anything and get the answer directly in your keyboard, inside any app.
Compare with competitors →Create, save, and reuse custom prompts. Pitching clients or sending updates? Type your prompt keyword and expand it to complete text inside any app.
Great for freelancers →No subscription trap. Buy credit packs starting at $5 and spend only when executing AI operations. Basic typing features remain free forever.
See all features →Normal typing never leaves your phone — no typing analytics, no learning. Only text you explicitly send to an AI prompt is processed, and those prompts and responses are saved to your account history. Password and OTP fields are never touched.
AI grammar checker →Works seamlessly in WhatsApp, Gmail, Instagram, Slack, and any app you type in.
Select your text, tap a prompt — Synapse runs AI and replaces your text in seconds. Here are real ways people use it every day.
Paste the client's message, tap one prompt — Synapse writes a professional, friendly reply in their language. No more staring at a blank chat.
Tell the AI what you need to say, tap the prompt — get a polished, professional email ready to send from Gmail, Outlook, or any mail app.
A long email lands in your inbox. Copy it, tap the prompt — Synapse reads it and writes a clear, formal reply that covers every point. Short and polished.
Type the topic, tap the prompt — get a thoughtful, natural-sounding comment that adds value. Friendly and conversational, never robotic.
Write “Translate to French”, “Translate to German”, or any language you need. The AI handles the rest — meaning and tone kept intact.
Describe your offer or skills, tap the prompt — get a confident proposal ready for LinkedIn, Upwork, or any job platform. Save it, reuse it every time.
Whatever your prompt is, that becomes the use case for you. Try it free
Less than 2 minutes from download to your first AI response.
Grab the APK from the Download section and install it. Enable 'Unknown sources' if prompted — this is normal for APKs outside the Play Store.
Open the app, tap 'Enable Synapse Keyboard', toggle it on in system settings, then set it as your default input method. Done in under 60 seconds.
Open any app — WhatsApp, Gmail, Reddit. Type your text, tap Select All in the keyboard toolbar, then tap the Synapse icon and pick a prompt like "Reply professionally" or "Translate to Urdu".
The AI's answer replaces your text when it's ready — usually a few seconds, depending on the prompt. Review and send. No app switching, no copy-pasting to ChatGPT.
Pay once, use forever. Pay with crypto and get 30% more credits on every package.
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Energy credits are non-refundable — start with $5 and top up only if it works for you. Know before you buy →
Everything you need to know about Synapse AI Keyboard.
Synapse is an AI-powered Android keyboard that works in every app where you type — WhatsApp, Gmail, Instagram, Twitter, and more. Highlight any text or tap the AI button to rewrite, translate, fix grammar, or generate content instantly.
Three steps: (1) Download the APK and install it — allow 'unknown sources' when prompted. (2) Open Synapse, tap 'Enable Synapse Keyboard' and toggle it on in system settings. (3) Select Synapse as your default input method. The app includes a guided setup on first launch.
Energy credits power every AI request. Each action — improving text, translating, fixing grammar, generating content — uses a small amount based on input and output size. New accounts start with 20,000 free credits. Credits never expire and sync in real-time between the mobile app and web dashboard.
Visit the Pricing section and choose between card (via Gumroad) or crypto (via Cryptomus). Card payments deliver a license key to your email that you redeem on the dashboard. Crypto payments credit your account directly — no key needed. Every package is a one-time purchase, no subscription.
Crypto has lower processing fees and no chargeback risk, so we pass those savings to you as bonus credits. Pay with crypto and get 30% more credits on every package. For example, the $30 Max pack gives 3M credits with card but 3.9M with crypto. USDT payments are supported.
Download the Synapse AI Keyboard APK and start using AI in every app within minutes. Free to install, 20,000 credits included.
20K
Free credits
Safe
Verified APK
8.0+
Min Android
~38 MB
Download size
Safe to install
Google Play Protect still scans the app on your device when you install it. You'll just see a one-time “allow from this source” prompt — tap Allow, then Install. That's the only extra step versus the Play Store.