Core Architecture & Fare Taxonomy
Foundational fare taxonomy, event topology, smart-card schema mapping, and the security boundaries that keep settlement auditable end-to-end.
Public Transit Fare Collection
& Revenue Reconciliation Automation
A production-focused engineering resource for the people who keep transit revenue accurate. Turn raw taps, scans, and vendor settlement files into auditable financial records with deterministic, type-safe Python pipelines.
Built for transit operations teams, revenue analysts, and mobility-tech developers, the guides here cover the full reconciliation lifecycle: smart-card data parsing, fare-rule validation, agency settlement calculation, fraud-pattern detection, GTFS-RT synchronization, batch reconciliation, and compliance reporting.
Every section pairs architectural guidance with runnable, copy-ready code — so you can move from opaque binary dumps and rate-limited APIs to sub-0.1% variance settlement without manual forensic accounting.
Explore the sections
Five focused sections, organized from architecture and ingestion through fare math, revenue reconciliation, and fraud protection. Follow any topic link to reach a detailed, code-first walkthrough.
Fare Data Ingestion & GTFS-RT Sync
Bring heterogeneous AFC telemetry under control — GTFS-RT sync, CSV batch parsing at scale, vendor API extraction, and schema validation pipelines.
Fare Rule Validation & Calculation Engines
Deterministic fare math — transfer windows, discount eligibility, graceful offline fallback, and peak-pricing threshold tuning.
Fraud Detection & Revenue Protection
Protect revenue without penalizing riders — real-time tap anomaly scoring, fare-evasion analytics, and automated contactless chargeback reconciliation.
Revenue Reconciliation & Settlement
Turn priced taps and vendor settlement files into an audit-ready ledger — daily variance reconciliation, inter-agency clearing, hash-chained audit trails, and NTD reporting.
Start here
Hand-picked, code-first walkthroughs that show the reconciliation pipeline end to end — from raw tap decoding to deterministic fare math.
- Smart-card parsing Decoding Calypso Smart Card Transaction Logs Turn opaque Calypso binary dumps into structured, auditable tap records.
- Smart-card parsing Parsing MIFARE DESFire EV2 Tap Data in Python Decode DESFire EV2 application files into typed Python fare events.
- Data ingestion Optimizing Pandas Chunksize for 10M-Row Fare Files Stream multi-gigabyte settlement exports without exhausting memory.
- Validation Implementing Pydantic Models for AFC Event Streams Enforce type-safe contracts on noisy AFC event feeds at the boundary.
- Fare math Calculating Cross-Operator Transfer Windows with Python Model transfer eligibility across operators with deterministic rules.
- Resilience Building Graceful Degradation for Offline Fare Readers Keep charging correct fares when validators drop offline mid-service.
- Reconciliation Matching Settlement Files to Tap Ledgers Tie acquirer settlement rows back to the tap ledger and bucket every mismatch.
- Revenue protection Detecting Card Sharing with Tap Velocity Checks Flag one card tapping two places too far apart to be the same rider.