Correctly - AI Writing Assistant Built Into Your Keyboard
Correctly is a revolutionary AI-powered keyboard application that transforms how users write on mobile devices. By integrating advanced AI capabilities directly into the keyboard interface, the app eliminates the need to switch between applications while providing intelligent writing assistance, corrections, and translations in real-time.
Project Overview
The challenge was clear: mobile users struggle with writing errors, language barriers, and inefficient communication workflows. Traditional writing assistants require constant app-switching, breaking the natural flow of conversation. Correctly solves this by embedding AI directly into the keyboard, making powerful writing tools accessible with a single tap.
The application serves over 50,000 active users across iOS and Android platforms, processing more than 1 million messages with a 99.9% accuracy rate. Users report writing 3x faster while maintaining professional quality across all their communications.
Key Features
Correctly offers eight comprehensive AI-powered features designed to enhance every aspect of mobile writing:
Fix - Grammar & Spelling: Advanced error detection and correction that works in real-time as users type, catching common mistakes before they become embarrassing errors in important messages.
Polish - Multiple Tones: Intelligent tone adjustment allowing users to rewrite content in Professional, Casual, Friendly, Formal, or Concise styles with a single tap, perfect for adapting communication to different contexts.
Translate - 60+ Languages: Instant translation capabilities that break down language barriers, enabling global communication without leaving the keyboard interface.
Summarize - Long Text: Automatic summarization of lengthy messages and documents, helping users quickly digest and respond to complex information.
Smart Reply - Context-Aware: AI-generated response suggestions that understand conversation context and provide three intelligent reply options for any message.
Custom - Your Rules: Personalized text processing based on user-defined custom instructions, allowing for individualized writing assistance that adapts to specific needs and preferences.
Search Docs - Find Instantly: Integrated document search functionality that allows users to quickly find and insert relevant information from their personal documents.
Smart Write - Auto-Complete: Intelligent text completion that predicts and suggests contextually appropriate continuations for partially written text.
Technology Stack
The application leverages a modern, scalable technology architecture designed for performance and reliability:
Mobile Development: Native iOS and Android applications built with platform-specific frameworks to ensure optimal performance and deep system integration for keyboard functionality.
AI & Machine Learning: Advanced natural language processing models optimized for mobile devices, with cloud-based processing for complex operations and on-device inference for real-time features.
Backend Infrastructure: Scalable cloud architecture handling user authentication, subscription management, and AI model serving with high availability and low latency.
Data Processing: Efficient text processing pipelines optimized for mobile constraints, with intelligent caching and compression to minimize data usage.
Security: End-to-end encryption for user data, privacy-first design principles, and secure API communication to protect sensitive user information.
Challenges and Solutions
Challenge 1: Keyboard Integration Complexity
Developing a custom keyboard that seamlessly integrates with both iOS and Android platforms while maintaining native feel and performance presented significant technical challenges. Each platform has different APIs, restrictions, and user expectations for keyboard behavior.
The solution involved creating a unified architecture with platform-specific implementations that respect each operating system's design principles while providing consistent functionality. Extensive testing across device types and OS versions ensured compatibility and performance optimization.
Challenge 2: Real-Time AI Processing
Providing instant AI-powered suggestions without noticeable latency required careful optimization of both local processing and cloud communication. Users expect keyboard responses to be immediate, making performance a critical success factor.
The team implemented a hybrid approach combining on-device processing for simple corrections with intelligent cloud processing for complex AI features. Smart caching, predictive loading, and adaptive quality settings based on network conditions ensure consistently fast responses.
Challenge 3: User Privacy and Data Security
As a keyboard application, Correctly has access to all user text input, making privacy and security paramount concerns. Users needed assurance that their sensitive communications would remain private while still benefiting from AI assistance.
The solution included implementing end-to-end encryption, local processing for sensitive operations, minimal data retention policies, and transparent privacy controls. Users can choose their privacy level, and all data handling follows strict security protocols with regular security audits.
Challenge 4: Multilingual AI Accuracy
Supporting 60+ languages with high accuracy across different writing styles, contexts, and regional variations required sophisticated language model training and optimization.
The development team trained specialized models for different language families, implemented context-aware processing that considers cultural nuances, and created feedback loops for continuous accuracy improvement based on user interactions.
Results
Correctly has achieved remarkable success metrics that demonstrate both user satisfaction and technical excellence:
User Growth: Reached 50,000+ active users within the first year of launch, with consistent month-over-month growth and strong user retention rates across both iOS and Android platforms.
Performance Metrics: Processed over 1 million messages with 99.9% accuracy rate, demonstrating the reliability and effectiveness of the AI models and processing infrastructure.
User Satisfaction: Maintained an average rating of 4.8 stars on the App Store and 4.7 stars on Google Play, with users consistently praising the app's ease of use and effectiveness.
Productivity Impact: Users report writing 3x faster than before, with significant improvements in communication quality and reduced time spent on editing and revising messages.
Market Penetration: Successfully captured users across diverse demographics and use cases, from business professionals to students to international users requiring translation services.
Revenue Growth: Achieved sustainable revenue through freemium model with 500 free words per month and Pro subscription at $1.00/month, with strong conversion rates from free to paid users.
Technical Achievements
The project delivered several notable technical accomplishments that set new standards for AI-powered mobile applications:
Seamless Integration: Created a keyboard experience that feels native to each platform while providing advanced AI capabilities, solving the long-standing challenge of making third-party keyboards feel natural.
Performance Optimization: Achieved sub-100ms response times for most AI features through intelligent architecture and optimization, meeting the strict performance requirements of keyboard applications.
Scalable Architecture: Built infrastructure capable of handling millions of API requests with high availability and consistent performance, preparing for future growth and expansion.
Cross-Platform Consistency: Delivered feature parity across iOS and Android while respecting platform-specific design principles and user expectations.
Conclusion
Correctly represents a significant advancement in mobile AI applications, successfully solving the fundamental problem of writing assistance accessibility. By embedding powerful AI directly into the keyboard interface, the project eliminated friction in the user experience while providing enterprise-grade writing tools to everyday mobile users.
The success of Correctly demonstrates the potential of thoughtfully integrated AI to enhance daily workflows without adding complexity. The project's focus on user privacy, performance, and genuine utility has created a sustainable product that continues to grow and evolve with user needs.
The lessons learned from building Correctly - particularly around AI optimization, cross-platform development, and user experience design - provide valuable insights for future AI-powered consumer applications. The project stands as a testament to the power of solving real user problems with elegant, technology-driven solutions.