> ## Documentation Index
> Fetch the complete documentation index at: https://docs.centsless.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Centsless API: Cash Rounding Compliance for POS Vendors

> Centsless handles jurisdiction-aware cash rounding for every state with enacted rounding legislation. One API integration gives every merchant on your platform full compliance.

Centsless is the compliance infrastructure layer for cash rounding in the post-penny economy. POS vendors integrate once through the Centsless API, and every merchant on their platform automatically gets the correct rounding rule for their location — with a cryptographic audit trail on every transaction.

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Process your first jurisdiction-aware transaction in under 5 minutes.
  </Card>

  <Card title="Authentication" icon="key" href="/authentication">
    Learn how to get an API key and authenticate every request.
  </Card>

  <Card title="Jurisdiction Resolution" icon="map-pin" href="/concepts/jurisdiction-resolution">
    Understand how the engine resolves the correct rounding rule for any location.
  </Card>

  <Card title="API Reference" icon="code" href="/api-reference/overview">
    Browse every endpoint with request/response schemas and examples.
  </Card>
</CardGroup>

## Why Centsless

Penny production ceased in November 2025. Six states have enacted cash rounding legislation, each with a different methodology and enforcement model — and no federal standard exists. Every cash transaction in America now requires a compliance decision.

<CardGroup cols={2}>
  <Card title="Multi-state coverage" icon="map">
    One integration covers all enacted jurisdictions. New legislation is added automatically — no redeployment required.
  </Card>

  <Card title="Immutable audit trail" icon="shield-check">
    Every transaction is cryptographically hashed into a tamper-evident chain. Overrides, voids, and refunds are tracked with employee attribution.
  </Card>

  <Card title="Real-time fraud scoring" icon="chart-line">
    Every transaction receives a fraud score and risk level based on rounding patterns, void rates, and override behavior.
  </Card>

  <Card title="Compliance export" icon="file-csv">
    Export a 53-field CSV with the complete transaction lifecycle for regulatory reporting and audit evidence.
  </Card>
</CardGroup>

## Get started in 4 steps

<Steps>
  <Step title="Get an API key">
    Contact Centsless to obtain sandbox credentials. Sandbox keys are rate-limited to 1,000 requests/hour.
  </Step>

  <Step title="Make your first call">
    Send a transaction with your merchant ID, amounts, payment method, and a ZIP code. The engine handles jurisdiction resolution automatically.
  </Step>

  <Step title="Review the response">
    The response includes the legally correct rounded amount, compliance status, fraud score, and audit hash — all in one call.
  </Step>

  <Step title="Go live">
    When you're ready for production, contact Centsless to promote your integration. Production keys support 10,000 requests/hour.
  </Step>
</Steps>

## Enacted states

| State      | Bill     | Method                     | Enforcement |
| ---------- | -------- | -------------------------- | ----------- |
| Arizona    | HB 2938  | Swedish rounding           | Mandatory   |
| Indiana    | SB 243   | Three-tier operator choice | Permissive  |
| Tennessee  | HB 1744  | Symmetrical (safe harbor)  | Voluntary   |
| Washington | SHB 2334 | Symmetrical                | Permissive  |
| New Mexico | HB 291   | Delegated to Dept          | Narrow      |
| Utah       | HB 597   | Not prescribed             | Narrow      |

<Note>
  All six states require sales tax to be calculated on the **pre-rounded** amount. Centsless handles this automatically.
</Note>