- Reduces GoCardless API calls by up to 99% through intelligent caching of transaction data
- Secure AES-GCM encryption with PBKDF2 key derivation (200k iterations) for at-rest storage
- Automatic range merging and transaction deduplication to minimize storage and API usage
- Cache-first approach with automatic fetching of uncovered date ranges
- Comprehensive test suite with 30 unit tests covering all cache operations and edge cases
- Thread-safe implementation with in-memory caching and encrypted disk persistence
- Validate amounts are non-zero and within reasonable bounds (≤1B)
- Validate currency codes are 3 uppercase ASCII letters
- Apply validation to main and foreign amounts/currencies
- Add comprehensive tests for validation logic
- Maintain graceful error handling for invalid data
- Implement robust End User Agreement expiry detection and handling
- Add graceful error recovery for failed accounts
- Rewrite README.md to focus on user benefits
- Add documentation guidelines to AGENTS.md
