LEGER_OS // Personal Finance Mainframe

Empirical Liquidity Engine & Zero-Credential Financial Intelligence

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Mobile-First Architecture & Platform Access

IMPORTANT: LEGER_OS is architected primarily as a mobile-first operating system (Android Native .apk / Mobile Progressive Web App).

The core automation capabilities—such as Zero-Credential Android Push Ingestion and iOS Apple Wallet Automations—require a mobile device to capture real-time payment events. Desktop browsers are fully functional for deep ledger audits, but mobile is the primary intended form factor.

• Web Application / PWA: https://leger-os.vercel.app (Install via Safari / Chrome "Add to Home Screen")
• Android Native APK: Download Direct APK

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The Core Problem: Why Aggregators Fail

Traditional personal finance applications (YNAB, Monarch, Copilot) charge $70–$120/year while relying on third-party Open Banking aggregators (Plaid, Salt Edge, GoCardless). In practice:

1. High Sync Failure Rate (~22%): Bank API connections routinely break, requiring constant re-authentication.
2. Privacy Vulnerabilities: Users must hand over banking login credentials to foreign third-party intermediaries.
3. Rigid Calendar Slicing: Incumbents force tracking into calendar months (Day 1–31), ignoring real-world bi-weekly, 4-week, or irregular salary deposit cycles.

LEGER_OS eliminates aggregators entirely by replacing them with local device-level notification listeners and webhook automations.

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Key Engineering Features

1. Universal Zero-Credential Android Ingestion

• Uses a custom Capacitor Java plugin (LegerBankSyncPlugin) with a native NotificationListenerService.
• Zero Storage: Payment push notifications are processed in device memory via deterministic regex parsing to extract merchant, amount, and currency. The raw text and any PII/OTPs are discarded immediately.
• Agnostic to Any Bank: Supports any banking application, digital wallet (MB WAY, Apple Pay, Google Wallet), fintech (Revolut, Wise, N26), or broker (XTB, Trade Republic) installed on your device.

2. iOS Apple Shortcuts Integration

• Provides a secure, private webhook endpoint (/api/transactions/device-push).
• Integrates directly with native Apple Shortcuts automations triggered upon Apple Pay transactions with zero cloud credential sharing.

3. Mathematical Projection Engine & Recency Decay

Future liquidity is projected daily using statistical analysis rather than static historical averages:

• Recency Decay Weighting ($\lambda = 0.12$): Spending velocity applies exponential time-decay weighting (~6-day half-life), prioritizing recent spending momentum over older expenses.
• Heavy Current Cycle Alpha ($\alpha \ge 0.65$): Forecasts favor the active paycheck cycle over distant historical baselines: $$\alpha = \min(1.0, 0.65 + 0.35 \cdot (\text{days elapsed} / \text{total days}))$$
• Zero Synthetic Interpolation: Plotted charts only map executed transactions or verified market ticks—never synthetic linear price interpolations.

4. Multi-Provider Conversational AI Bridge

Integrated neural interface supporting custom API keys and local offline inference:

• Google Gemini (gemini-2.5-pro)
• OpenAI (gpt-4o-mini)
• Groq (llama-3.3-70b-versatile)
• Local Ollama (100% free local offline inference without external API tokens)

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Tech Stack

• Frontend: Next.js 16.2 (Turbopack, App Router), React 19, Tailwind CSS 4, Lucide Icons, Recharts, Framer Motion.
• Backend & Database: Supabase (PostgreSQL with Row Level Security, Storage, Realtime).
• Mobile Runtime: Capacitor 6 with native Android Java bridge.
• AI Bridge: Multi-provider client wrapper with fallback heuristics.
• Hosting: Vercel Edge Runtime & Serverless Functions.

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Security & Privacy Safe-Deposit Standard

• Zero Bank Logins: LEGER_OS never asks for, stores, or transmits your banking credentials.
• Encrypted Transmission: All telemetry and database queries are transmitted over 256-bit SSL encryption.
• Isolated Multi-Tenant Storage: Secured by PostgreSQL Row Level Security (RLS) policies isolating user records strictly to authenticated IDs.

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License & Intellectual Property

Copyright © 2026 LEGER_OS. All Rights Reserved.

LEGER_OS is source-available software provided under a Strict Proprietary License.

• Allowed: Personal, non-commercial educational review, local evaluation, and security auditing.
• Prohibited: Commercial use, public hosted SaaS/cloud deployments, re-licensing, distribution, mobile app store republishing, or creating unauthorized commercial forks/derivatives.

For full terms and conditions, see the LICENSE file.