The Heart of
Hello Diary

A robust Spring Boot backend designed for ultimate privacy and high-speed multimedia performance.

storage

Secure Diary Storage

"Multimedia entries managed with PostgreSQL and Redis."

Your text, voice, and high-resolution images are stored with zero-knowledge encryption. We can't read your entries, ever.

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Media Pipelines

"Nginx-optimized delivery with automated background processing."

Images are automatically resized and voice notes compressed (128kbps AAC) within minutes of upload for a snappy experience.

subscriptions

RevenueCat Billing

"Industry-standard secure mobile application billing."

Tiered subscriptions are handled via HMAC-signed webhooks, ensuring idempotent and reliable payment processing.

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Advanced Media Handling

Our backend uses **Nginx-optimized pipelines** and **Flyway schema migrations** to handle massive multimedia uploads. Whether it's high-res photos or full-length voice entries, the system optimizes your data for performance without quality loss.

  • check_circle Background Audio Compression
  • check_circle PostgreSQL Vector-based Filtering
Multimedia Processing Pipeline
insights

Engagement & Productivity

More than just a diary. Our backend tracks **Productivity Analytics** and **Engagement Streaks** to keep you moving forward. Motivational messages are generated dynamically based on your habits.

  • check_circle Real-time Streak Tracking
  • check_circle Contextual To-do Integration
Integrated Motivation and Task Tracking

Security & Architecture FAQ

What is your technical stack? expand_more

Hello Diary is built on Spring Boot 3+ for its core logic, utilizing PostgreSQL for structured data and Redis for high-speed caching. Our administrative tools are built with Vaadin Flow for a reactive and secure management interface.

  • Spring Modulith
  • JWT Authentication
  • AES-256 Encryption
  • Flyway Migration
How is my privacy protected from AI? expand_more
A foundational pillar of our architecture is **No AI Analysis**. While we offer early access to optional user-facing AI tools for premium members, our backend logic explicitly excludes your private diary entries from any sentiment analysis, behavioral engines, or training models.
How secure is the RevenueCat integration? expand_more
We use industry-standard HMAC-signed webhooks to receive billing updates from RevenueCat. This ensures that only verified Google and Apple Store purchases can trigger premium access, protecting your account from fraud.