WriteBetter
WriteBetter is an AI-powered custom keyboard for Android and iOS that helps users write clearer, more confident messages without leaving the app they are using. Users can change the tone, rewrite text, translate content, or generate a smart reply through native keyboards built with Kotlin and Swift.
- Industry
- AI · Productivity · Mobile
- Discipline
- AI Productivity
Technologies Used
Product Overview
WriteBetter provides an AI-enabled custom keyboard for Android and iOS. While typing in supported chat, email, social media, and productivity apps, users can rewrite text, change the tone, translate content, or create a smart reply, then insert the result directly into the conversation. Each platform also includes a companion app for managing settings, themes, and subscriptions.
The Challenge
Building a custom keyboard requires fast interaction, compatibility across supported apps, careful privacy handling, and AI features that do not interrupt the typing experience. The goal was to make rewriting and smart replies feel like a natural part of typing rather than a separate tool users must open.
A Real Custom Keyboard, Not a Wrapper
On Android, WriteBetter runs as a native input method editor (IME) and manages the complete typing experience, including letters, numbers, symbols, shift and caps lock, key previews, long-press actions, and repeated deletion. AI actions, Paste Mode, Smart Replies, Translation, and Clipboard tools are available through panels inside the keyboard. The iOS version provides a similar experience through a native Swift implementation designed for iOS.
AI that Lives in the Keyboard
Tones and rewrites let users instantly turn a rough sentence into something professional, casual, witty, or persuasive. Smart Replies suggest context-aware responses, Translation switches languages on the fly, and voice typing turns speech into clean text, all without copying text out to another writing app.
Personalization and Polish
Users can personalize the keyboard with themes, font styles, an additional number row, an expanded space bar, haptic feedback, and keyboard-height settings. Saved preferences keep these settings consistent between the keyboard and the companion app. An onboarding tour and tooltips help users discover the available AI features.
Built to Ship and Scale
Firebase supports analytics and crash reporting, while the in-app subscription system manages access to premium tones and features. WriteBetter is available on the App Store and Google Play under Webnyxa Technologies, with updates released across both platforms.
A Backend Designed to Control Cost and Abuse
The keyboard connects to a NestJS API running on AWS Lambda. Previously, every request—including repeated or abusive requests—could invoke Lambda and increase backend usage. The request flow was reorganized into three protection layers. Amazon CloudFront caches public configuration responses, AWS WAF applies per-IP rate limits and configured security rules, and API Gateway limits bursts before requests reach Lambda. A forwarded origin secret helps prevent direct requests from bypassing CloudFront and reaching the gateway. Edge caching reduced Lambda invocations for cacheable configuration routes from approximately 10,000 per hour to single digits while also helping control abusive traffic.
Key Features
Outcomes
- WriteBetter is available on the App Store and Google Play.
- Users can access AI writing assistance from the keyboard without switching to a separate writing app.
- Native Android and iOS implementations provide an experience suited to each platform.
- CloudFront caching reduced Lambda invocations for cacheable configuration routes from approximately 10,000 per hour to single digits.
- AWS WAF rate limiting and security rules help stop abusive and malicious requests before they reach the backend.
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