# Crinkl — Verified Commerce Protocol

> Crinkl turns receipts into cryptographic proofs of real-world spending. Facts first. Identity detached.

## What Crinkl Does

Users scan grocery, restaurant, and retail receipts. Each receipt goes through OCR extraction, store resolution, and cryptographic attestation — producing a signed **spend token** with an Ed25519 signature from the Crinkl issuer. These tokens are aggregated into daily **Gross Merchandise Value (GMV)** totals, each backed by a Merkle tree with verifiable inclusion proofs.

Rewards are issued in Bitcoin (satoshis) via Lightning Network. Reward allocations are committed in Merkle-rooted **reward commitment tokens** before payout — preventing retroactive manipulation.

## Data Available

- **Verified GMV** — finalized alpha GMV through 2026-01-25 plus live beta cumulative GMV from 2026-01-27 onward, with daily summaries and proofs
- **Spend signals** — recent verified receipt activity with store category and metro area (CBSA)
- **Merchant analytics** — category distribution, top brands, spend concentration
- **Geographic distribution** — spend breakdown by category and CBSA metro code
- **Bitcoin settlement stats** — BTC price, sats/receipt, Lightning payouts, active wallets
- **Cryptographic proofs** — Merkle inclusion proofs, reward commitments, end-to-end verification
- **Issuer keys** — Ed25519 public key for independent signature verification

## MCP Server

An MCP server is available for AI agents and LLMs to query this data programmatically:

- **Endpoint**: https://mcp.crinkl.xyz/mcp
- **Transport**: Streamable HTTP (stateless)
- **Tools**: 15 public read-only tools plus 6 agent tools (21 total)
- **Authentication**: Read-only tools are public. Pairing and vendor discovery are no-auth. Receipt submission and agent earnings require an API key after human approval in the PWA.
- **Server card**: https://mcp.crinkl.xyz/.well-known/mcp.json

## Public API

REST API at https://api.crinkl.xyz with public analytics/proof endpoints plus agent endpoints for pairing, vendor discovery, receipt submission, and scoped stats.

## Key Properties

- **Cryptographically verifiable**: Every data point traces to an Ed25519-signed attestation token
- **No PII**: Spend signals contain store category and metro area — never personal information
- **Real commerce**: All figures are from actual receipt scans, not synthetic data
- **Bitcoin-settled**: Rewards are real satoshis paid via Lightning Network

## Links

- Website: https://crinkl.xyz
- App: https://app.crinkl.xyz
- API: https://api.crinkl.xyz