Cryptographic Audit Chain
Append-only audit events, consecutive mileage checks, time-overlap prevention, and SHA-256 hash chains guarantee auditability at the database level.
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Multi-tenant, mobile-first application for audit-proof logging of business trips, receipts and expenses – featuring cryptographic SHA-256 hash chains and automated OCR odometer recognition.
Context & Insight
Origin & Motivation
Born from the need to eliminate error-prone Excel spreadsheets and scattered odometer photos: A pragmatic, self-hostable system that automates statutory reporting duties for freelancers, small businesses, and non-profits so that day-to-day logging is painless and tax audits are effortless.
Automated OCR Recognition
Automated extraction of odometer values from photos and receipt amounts for rapid plausibility checks without manual typos.
Modern Headless Architecture
Decoupled Laravel 12 backend with OpenAPI interface, React 19 with TypeScript, Ionic 8 and Capacitor 7 for responsive PWA and native mobile deployment.
Tenant Isolation & Export
Strict server-side tenant isolation, OAuth2 via Laravel Passport, encrypted third-party credentials (InvoiceNinja), and verifiable export archives with checksums.
Technical Implementation in Detail
Backend Layer
Headless REST API & Security
PHP 8.4 & Laravel 12. OAuth2-Authentifizierung über Laravel Passport, rollen- und mandantenspezifische Zugriffskontrolle mit Spatie Permissions, serverseitige Hash-Ketten-Bildung und verschlüsselte Drittanbieter-Anbindungen (InvoiceNinja).
Frontend & Mobile
PWA & Cross-Platform Client
React 19 mit TypeScript, Vite und Ionic 8. Ausgelegt für Offline-Nutzung mit lokaler Datenhaltung und automatischer Synchronisation beim Wiederverbinden. Durch Capacitor 7 nativ paketierbar für iOS und Android.
DevOps & Sandbox
Automatisierte Ephemeral Sandbox
GitLab CI/CD Pipeline-Trigger mit dynamischer Subdomain-Zuweisung über Wildcard-DNS (*.labs.est-in.eu) und Let's Encrypt SSL-Terminierung. Automatischer Auto-Stop nach 15 Minuten für risikofreies Testen.