Integrate the Rule Layer
Keep the existing transaction flow. Centsless is designed to resolve the applicable rule, calculate the rounding outcome and return both the result and its evidence for the POS to apply.
POS and Merchant Portals Now Live
Explore our demo dashboards to see how Centsless compliance infrastructure works from both the POS vendor and merchant perspective.
What Centsless Is, Architecturally
A rule-determination, calculation and evidence engine, not a ledger or payment system.
Decision Layer
An API-driven layer that selects the governing authority and returns the transaction action. Federal law is another versioned rule layer, not a hard-coded exception.
Does Not Alter the Ledger
Centsless returns a calculated rounding result and its evidence. It does not write to, reconcile, or modify the primary ledger record.
Evidence Context
The response can preserve the authority, version, effective date, transaction conditions, adjustment, and settlement context needed for later review.
Module-level detail is documented on the platform page.
Conceptual example, not a published API contract
A transaction context in, a decision out
This illustrates the shape of the exchange, not an endpoint. Field names, formats, and the endpoint itself are confirmed during integration scoping.
Example input
- ZIP code: 30301
- Transaction total: 14.07
- Tender: cash
- Direction: cash out (change due)
- Actor: retail merchant
- Transaction type: sale
- Date: transaction timestamp
Example output
- Authority: governing statute or agency guidance
- Rule: current version for the resolved authority and context
- Decision: round, do not round, or exclude
- Adjusted amount: rounded cash total, where applicable
- Explanation: why this rule governed this transaction
- Evidence reference: pointer to the preserved decision record
Conceptual request and response
Rule resolution, not another checkout
The fields below describe what the integration is designed to support. They are conceptual and do not represent a published API contract. Endpoint details are confirmed during integration scoping.
Transaction context in
- • Jurisdiction
- • Tender
- • Transaction type
- • Amount
- • Date and time
- • Operational context
Decision context out
- • Applicable rule
- • Calculated rounding result
- • Allowed or required action
- • Rounding increment and direction
- • Authority and rule version
- • Effective date and rationale
- • Evidence metadata
Integration Constraints
The behaviours an engineer needs in order to evaluate fit.
Cash-Only Rounding
Rounding applies to cash tender only. Card, EBT, and digital payments pass through unmodified. EBT tender is excluded from rounding, a behaviour designed against 7 CFR 278.2(b).
Reversible Operations
Every rounding operation is reversible, and refund normalization applies symmetric treatment in the opposite direction.
No Lock-In, No Tender Interference
No proprietary data store is required, and tender selection at the register is untouched.
Deterministic Outputs
Identical inputs produce identical outputs. Integer-cent arithmetic, no floating-point drift.
What the Integration Requires
- Send the transaction context needed for rule resolution
- Store both exact and rounded amounts in transaction records
- Update receipt templates to display dual totals
- Add merchant-level enable/disable configuration
- Implement logging for audit and compliance review
- Link audit records to the record before them so the log re-verifies end to end
Available on Request
Integration materials and technical evaluation options are discussed during pilot scoping rather than published openly.
API Reference
Endpoint reference and integration guide for platform engineering teams.
Technical Evaluation
Integration materials and technical evaluation options are discussed during pilot scoping.
Evaluating an Integration?
Integration materials and technical evaluation options are discussed during pilot scoping.
Developers and integration: developers@centsless.org