Developers/UCP Integration

Universal Commerce Protocol Integration

Enable AI agents and commerce platforms to discover seller verification status through the UCP standard. Expose trust signals that help buyers make informed decisions.

UCP Specification JSON Schema

What is UCP?

The Universal Commerce Protocol (UCP) is an open standard co-developed by Shopify and Google for agentic commerce. It allows AI agents, shopping assistants, and platforms to discover merchant capabilities, process transactions, and access trust information through a unified API.

Bazar provides a UCP extension (com.bazarproof.seller_verification) that exposes seller verification status, trust scores, and blockchain attestations to any UCP-compatible platform.

The Seller Verification Extension

Extension Details

Namecom.bazarproof.seller_verification

Version2026-01-11

Extendsdev.ucp.shopping.checkout

Data Provided

Verification status and level
Trust score (0-100)
Display badges with labels and colors
Blockchain attestation proofs
Cryptographic proof URLs

Discovery Methods

AI agents can discover a merchant's verification status using any of four lookup methods. This flexibility allows agents to query by whatever identifier they have available.

By Merchant ID

/.well-known/ucp?merchantId=merchant_123

Use the internal Bazar merchant ID. Best when you have a direct reference.

By Shopify Domain

/.well-known/ucp?shop=mystore.myshopify.com

Use the Shopify myshopify.com domain. Ideal for Shopify integrations.

By Platform Account

/.well-known/ucp?platform=amazon&accountId=seller_123

Use a platform identifier and account ID for marketplace integrations.

By Primary Domain

/.well-known/ucp?domain=www.mystore.com

Use the merchant's primary domain. Best for general web discovery.

Merchant Control

Merchants can disable UCP discovery in their Bazar settings. When disabled, all lookup methods return a 404 with the message "UCP discovery is disabled for this merchant".

API Reference

Base URL: https://api.bazarproof.com

Non-Shopify platforms should link accounts first via the platform linking endpoint before using UCP discovery.

GET/.well-known/ucp

Discovery endpoint for UCP business profile. Supports multiple lookup methods.

Parameters: One of: merchantId, shop (myshopify domain), platform + accountId, or domain (primary domain)

GET/ucp/v1/seller-verification/:merchantId

Get seller verification data in UCP format

Parameters: merchantId in path

GET/ucp/v1/seller-verification/:merchantId/proof

Get cryptographic proof for verification

Parameters: merchantId in path

POST/ucp/v1/seller-verification/:merchantId/validate

Validate a proof submitted by agent/platform

Parameters: merchantId in path, proof in body

Verification Levels

Bazar verification levels map to UCP values as follows:

Bazar Level	UCP Value	Trust Score	Badge	Color
BASIC	`identity_verified`	75	Silver	`#C0C0C0`
STANDARD	`business_attested`	85	Gold	`#FFD700`
ENHANCED	`enhanced`	100	Platinum	`#E5E4E2`

Code Examples

Examples for integrating seller verification into your application.

{
  "ucp": {
    "version": "2026-01-11",
    "services": {
      "dev.ucp.shopping": {
        "version": "2026-01-11",
        "spec": "https://ucp.dev/specification/overview",
        "rest": {
          "schema": "https://ucp.dev/services/shopping/rest.openapi.json",
          "endpoint": "https://api.bazarproof.com/ucp/v1"
        }
      }
    },
    "capabilities": [{
      "name": "com.bazarproof.seller_verification",
      "version": "2026-01-11",
      "spec": "https://bazarproof.com/developers/ucp",
      "schema": "https://bazarproof.com/ucp/schemas/seller_verification.json",
      "extends": "dev.ucp.shopping.checkout"
    }]
  },
  "seller_verification": {
    "status": "verified",
    "level": "business_attested",
    "trust_score": 85,
    "verified_at": "2026-01-10T15:30:00Z",
    "verification_methods": ["identity", "business_registration"],
    "badges": [
      { "level": "business_attested", "label": "Business Attested", "color": "#FFD700" },
      { "level": "identity_verified", "label": "Identity Verified", "color": "#C0C0C0" }
    ],
    "attestations": [{
      "chain": "hedera",
      "transaction_hash": "0.0.123456@1704912600.123456789",
      "timestamp": "2026-01-10T15:35:00Z",
      "explorer_url": "https://hashscan.io/mainnet/transaction/0.0.123456@1704912600.123456789",
      "proof_type": "merkle"
    }],
    "proof_url": "https://api.bazarproof.com/ucp/v1/seller-verification/merchant_123/proof"
  }
}

Blockchain Attestations

Verification data is anchored on-chain using Merkle trees and the Hedera Consensus Service (HCS), providing cryptographic proof of verification with enterprise-grade security.

Hedera Consensus Service

Enterprise-grade blockchain anchoring with sub-second finality

All verification proofs are anchored using Hedera Consensus Service (HCS), providing tamper-proof, timestamped records with deterministic ordering. View proofs on HashScan.

Sub-second transaction finality
Carbon-negative network
Enterprise governance (Hedera Governing Council)

Proof Validation Steps

1Reconstruct leaf hash: Compute SHA-256 of the leaf data with sorted keys
2Verify Merkle path: Follow the proof path from leaf to root
3Check root match: Computed root should match the blockchain-anchored root
4Verify on blockchain: Check the transaction on the block explorer

Ready to integrate?

Start displaying trust signals to your users today.

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