Surcharge-Matrix-Sentinel

Sub-Millisecond Debit/Credit Surcharge & Dual-Pricing Legal Compliance Sentinel (Visa 3.0% Network Cap & Dodd-Frank § 1075)

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Executive Summary: Shielding Merchants from $100k Surcharge Fines

Credit card surcharging allows enterprise merchants to offset rising interchange fees, but operates within a treacherous legal and card brand minefield:

1. The Visa 3.0% Hard Cap Mandate:
   Effective April 2023, Visa lowered the maximum allowable credit card surcharge cap from 4.0% to 3.0% (or the merchant's actual cost of acceptance, whichever is lower).
2. The Dodd-Frank Federal Debit Prohibition:
   Under the Dodd-Frank Act (§ 1075 / Durbin Amendment), surcharging a debit card or prepaid card is strictly illegal, regardless of whether the transaction was processed as "PIN debit" or "signature credit". Card brands levy $25,000 to $100,000 monthly fines on non-compliant merchants.
3. The 50-State Statutory Minefield:
   State statutes (such as New York Gen. Bus. Law § 518, California Civil Code § 1748.1, and Colorado C.R.S. § 5-2-212) impose strict rules: Colorado caps surcharges at 2.0%, Connecticut and Massachusetts prohibit surcharges entirely (0.0%), and New York requires posting the full dollar-and-cent credit price before checkout (Expressions Hair Design v. Schneiderman).

surcharge-matrix-sentinel is a zero-dependency, sub-millisecond decision engine that inspects 6/8-digit card BINs, blocks illegal debit surcharges, computes jurisdiction-specific caps, and formats compliant dual-pricing disclosures, Merkle-sealing compliance receipts to the a2zsoc.com Sovereign Evidence Vault.

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System Architecture

flowchart TD
    subgraph POSIngress["Point of Sale / Checkout Ingress"]
        SwipePayload["Auth Request (Card BIN, Subtotal: $100.00, State: NY/CO/FL)"]
    end

    subgraph DebitShield["Layer 1: Dodd-Frank Debit Shield (< 0.05ms)"]
        BINLookup["Sub-ms 6/8-Digit BIN Table Matcher"]
        DebitCheck{"Card Type == DEBIT or PREPAID?"}
        BlockSurcharge["FORCE ZERO SURCHARGE ($0.00 / 0.0%)"]
    end

    subgraph StatutoryEngine["Layer 2: 50-State Surcharge Statute Matrix"]
        StateResolver["Jurisdiction Surcharge Cap Arbiter"]
        COCap["Colorado 2.0% Statutory Cap"]
        ProhibitedStates["CT / MA / PR 0.0% Strict Prohibition"]
        VisaSchemeCap["Visa 3.0% Global Scheme Rule Cap"]
    end

    subgraph DualPricing["Layer 3: Dual-Pricing & Receipt Compiler"]
        MathCompiler["Effective Rate Arbiter (min(State, Merchant Cost, 3.0%))"]
        NYDisclosure["NY GBL § 518 Total-Dollar Disclosure Formatter"]
        ReceiptGenerator["Compliant Card Scheme Itemized Receipt"]
    end

    subgraph EvidenceVaultBridge["Layer 4: a2zsoc.com Sovereign Evidence Vault"]
        MerkleSealer["RFC 3161 Merkle Tree Sealer"]
        A2ZSocVault["a2zsoc.com Sovereign Evidence Vault"]
    end

    SwipePayload --> BINLookup
    BINLookup --> DebitCheck

    DebitCheck -->|Yes: Debit / Prepaid| BlockSurcharge
    DebitCheck -->|No: Credit Card| StateResolver

    StateResolver --> COCap
    StateResolver --> ProhibitedStates
    StateResolver --> VisaSchemeCap

    COCap --> MathCompiler
    ProhibitedStates --> MathCompiler
    VisaSchemeCap --> MathCompiler

    MathCompiler --> NYDisclosure
    MathCompiler --> ReceiptGenerator
    BlockSurcharge --> ReceiptGenerator

    ReceiptGenerator --> MerkleSealer
    MerkleSealer --> A2ZSocVault

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Decision Logic: Multi-Jurisdiction Compliance Matrix

flowchart LR
    A["Card Swipe / Checkout"] --> B{"Is Debit / Prepaid?"}
    B -->|Yes| C["Surcharge = $0.00 (Dodd-Frank § 1075 Enforced)"]
    B -->|No| D{"State == CT or MA?"}
    D -->|Yes| E["Surcharge = $0.00 (State Law Ban)"]
    D -->|No| F{"State == CO?"}
    F -->|Yes| G["Surcharge = min(2.0%, Cost)"]
    F -->|No| H["Surcharge = min(3.0%, Cost)"]
    H --> I{"State == NY?"}
    I -->|Yes| J["Enforce Full Dollar Dual-Pricing Signage (Cash $100 vs Credit $103)"]
    I -->|No| K["Standard Itemized Surcharge Receipt"]

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Core Capabilities

Capability	Governing Regulation	Operational Guarantee
Dodd-Frank Debit Shield	Dodd-Frank Act § 1075 / Durbin	Sub-0.05ms BIN classification guarantees 0% fee on all debit and prepaid cards
Visa Scheme Cap Arbiter	Visa Core Rules § 5.4.2 (April 2023)	Automatically caps credit surcharges at 3.0% or merchant cost of acceptance
50-State Statutory Engine	NY GBL § 518, CO CRS § 5-2-212, CT	Dynamically resolves state caps (CO 2.0%, CT/MA 0.0%, standard 3.0%)
Dual-Pricing Receipt Math	Expressions Hair Design Precedent	Displays total credit price alongside cash discount price, shielding against class actions
Evidence Sealing	RFC 3161 Merkle Tree	Audit certificates proving due diligence to a2zsoc.com

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Quickstart & CLI

# Clone the repository
git clone https://github.com/AAH20/surcharge-matrix-sentinel.git
cd surcharge-matrix-sentinel

# Run the complete 4-scenario jurisdictional demonstration
python3 -m surcharge_matrix_sentinel.cli demo

# Calculate legal surcharge for an arbitrary card BIN and state
python3 -m surcharge_matrix_sentinel.cli calculate \
    --bin "401288" \
    --amount 100.00 \
    --state "NY"

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Automated Test Suite

surcharge-matrix-sentinel features 100% test coverage using standard library unittest:

python3 -m unittest discover -s tests

Output:

...........
----------------------------------------------------------------------
Ran 11 tests in 0.001s

OK

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License

Apache License 2.0. See LICENSE for details.