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GLOSSARY TERM

ACP (Agent Commerce Protocol)

ACP (Agent Commerce Protocol) defines standards and patterns for agent-initiated commerce on the agentic web. It encompasses pricing discovery, payment negotiation, automated settlement, and verifiable receipts for autonomous economic activity between agents and services.

Core ACP components

  • Pricing discovery - Machine-readable pricing through PEAC files, AIPREF, and HTTP 402 responses
  • Payment protocols - Standardized flows using HTTP 402, x402, and multi-rail settlement
  • Receipt verification - Cryptographic PEAC-Receipt tokens as proof of payment and access rights
  • Settlement rails - Support for fiat, stablecoins, crypto, and traditional payment processors
  • Compliance tracking - Auditable trail of all commercial transactions for regulatory requirements

How ACP works

  1. Service discovery - Agent finds service through search, referrals, or directories
  2. Policy reading - Agent fetches /.well-known/peac.txt for pricing and terms
  3. Price negotiation - Optional negotiation for bulk pricing or custom terms
  4. Payment initiation - Agent selects payment rail and initiates transaction
  5. Receipt issuance - Payment provider generates signed PEAC-Receipt JWS token
  6. Access granted - Agent presents receipt for verified access to paid resources

ACP pricing models

Pay-per-use

Micropayments for individual API calls, content access, or compute resources

Subscriptions

Time-based access with receipts issued for subscription periods

Tiered pricing

Volume-based pricing with automatic tier detection and billing

Dynamic pricing

Real-time price adjustments based on demand, time, or resource availability

ACP vs traditional payment APIs

Traditional Payments

  • Human-initiated checkout
  • Form-based input
  • Browser redirects
  • Manual approval flows
  • Email receipts

ACP

  • Agent-initiated transactions
  • Machine-readable protocols
  • Direct API flows
  • Automated settlement
  • Cryptographic receipts

Use cases

  • API marketplaces - Agents discover, purchase, and use APIs without human intervention
  • Content licensing - Automated payment for news articles, research papers, and media assets
  • Compute resources - Pay-per-use access to GPUs, storage, and processing power
  • Data access - Purchase real-time data feeds, datasets, and analytics
  • AI model usage - Per-token billing for LLM inference and specialized models

ACP compliance and security

  • Verifiable receipts - Cryptographically signed proof of payment preventing disputes
  • Audit trails - Complete transaction history for regulatory compliance
  • Rate limiting - Built-in protection against payment abuse and fraud
  • Offline verification - JWS receipts can be validated without issuer API calls
  • Multi-currency support - Standardized handling of fiat, stable coins, and cryptocurrencies

Learn more