ACP vs AP2: Protocol Comparison
Compare OpenAI & Stripe's Agentic Commerce Protocol with Google's Agent Payments Protocol to choose the right standard for your business.
Agentic Commerce Protocol
Focused on standardising checkout flows for AI agents. Emphasises merchant control, payment security, and compatibility with existing commerce infrastructure.
Learn more about ACP →Agent Payments Protocol
Designed for agent-to-agent transactions with platform independence. Emphasises interoperability, flexibility, and advanced multi-agent commerce scenarios.
Learn more about AP2 →Feature Comparison
| Feature | ACP | AP2 |
|---|---|---|
| Primary Focus | Standardised checkout flows | Agent-to-agent payments |
| Developed By | OpenAI & Stripe | |
| Licence | Apache 2.0 (Open Source) | Apache 2.0 (Open Source) |
| Integration Pattern | REST API / MCP Server | Protocol-agnostic |
| Payment Provider | Stripe (initially), extensible | Provider-agnostic |
| Primary Language | Language-agnostic (REST) | Python 3.10+ (primary) |
| Authentication | Bearer tokens, HMAC signatures | Google API Key / Vertex AI |
| Transaction Type | Physical, digital, subscriptions | Agent-to-agent, multi-party |
| Merchant Control | High (choose which agents) | Flexible (programmatic rules) |
| Platform Lock-in | Low (open standard) | None (protocol-agnostic) |
| First Implementation | ChatGPT Instant Checkout | Google ADK / Gemini |
| Best For | Traditional e-commerce businesses | Multi-agent marketplaces, B2B |
Key Differences Explained
Transaction Model
Optimised for traditional buyer-merchant transactions where an AI agent acts on behalf of a single user to purchase from businesses.
Designed for agent-to-agent commerce, enabling multiple AI agents to negotiate and transact directly with each other.
Implementation Complexity
Straightforward for businesses with existing Stripe integration. Well-defined REST endpoints make adoption quick.
More flexible but requires deeper integration work. Best suited for enterprises building custom AI commerce solutions.
Platform Strategy
Closely tied to OpenAI's ChatGPT ecosystem initially, with Stripe as the payment infrastructure partner.
Platform-agnostic by design, allowing integration with any AI framework, cloud provider, or payment processor.
Use Case Optimisation
Perfect for retail, e-commerce, subscription services—anywhere consumers buy products through AI assistants.
Excels in B2B procurement, multi-vendor marketplaces, and scenarios requiring complex agent negotiations.
Which Protocol Should You Choose?
Choose ACP if you:
- ✓Run a traditional e-commerce business
- ✓Already use Stripe for payments
- ✓Want to reach ChatGPT users quickly
- ✓Need a straightforward REST API integration
- ✓Sell physical goods, digital products, or subscriptions
- ✓Prefer merchant control over agent access
Choose AP2 if you:
- ✓Build multi-agent marketplace platforms
- ✓Need platform-independent solutions
- ✓Operate in B2B or enterprise procurement
- ✓Require agent-to-agent negotiation capabilities
- ✓Use Python-based AI development tools
- ✓Want maximum flexibility and customisation
Can You Support Both Protocols?
Yes, absolutely. Many forward-thinking businesses choose to implement both ACP and AP2 to maximise their reach across different AI platforms and use cases.
Since both protocols are open standards with clear specifications, there's no technical conflict in supporting both. Your business could use:
- •ACP for consumer-facing AI shopping experiences (ChatGPT, consumer AI assistants)
- •AP2 for B2B procurement agents or multi-agent marketplace scenarios
This dual-protocol approach ensures your business is discoverable across the entire agent commerce ecosystem, regardless of which standard gains more traction in specific market segments.
The Future of Agent Commerce Protocols
Both ACP and AP2 are in their early stages, and the agent commerce ecosystem is rapidly evolving. We may see:
- •Convergence of standards or interoperability layers between protocols
- •New protocols emerging from other major tech players (Amazon, Meta, Microsoft)
- •Industry consortiums forming to establish unified agent commerce standards
- •Payment network involvement (Visa, Mastercard) in protocol governance
By listing your business in the Agent Commerce Directory, you position yourself to adapt to whichever standards gain adoption, ensuring you're ready for the future of AI-powered commerce.
Ready to Enable Agent Commerce?
List your business in the Agent Commerce Directory and get discovered by AI platforms, regardless of which protocol you implement.
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