OpenSNAP

Open Self‑Negotiating API Protocol

Version: 1.0 • License: Apache 2.0

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Overview

OpenSNAP is a minimal, machine‑to‑machine HTTP handshake that lets autonomous agents discover API pricing, negotiate bids, and attach payment vouchers—independent of any particular settlement layer. Think of it as the TCP of metered API commerce: a simple “offer‑ack‑pay‑invoke” protocol that any payment rail (blockchain, Interledger, centralized ledger or Stripe) can plug into.

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Key Features

• Protocol‑First
  • Agnostic to payment networks: blockchain, Lightning, Interledger STREAM, or centralized tokens.
  • Extends OpenAPI with machine‑readable pricing metadata.
• Self‑Negotiating
  • Clients fetch x-price-base, x-pricing-algo, x-min-price, x-max-price, compute a bid, and send a CALL-OFFER.
  • Server responds with CALL-ACK (proceed) or CALL-REJECT (decline).
• Voucher‑Based
  • Payment proof carried as an HTTP header (X-OpenSNAP-Voucher), validated per request.
  • Settlement layer is pluggable (blockchain channels, ILP STREAM, centralized tokens).
• Play‑Money Reference
  • Includes an HMAC “voucher” adapter for zero-barrier prototyping.

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Files & Structure

/
├── examples/server.py    # Example FastAPI server implementing OpenSNAP
├── examples/client.py    # Example Python client demonstrating the handshake
└── rfc.md       # Protocol specification & message schemas

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Protocol at a Glance

1. Discovery

   GET /openapi.json

   Returns an OpenAPI spec extended with x-price-base, x-pricing-algo, x-min-price, x-max-price.

2. Negotiation

   • Client → Server (CALL-OFFER):

     X-OpenSNAP-Offer: {"endpoint":"/video/generate","bid":0.002}

   • Server → Client:
     • 200 OK (ACK) or 402 Payment Required (REJECT)

3. Payment & Invocation

   • Client attaches:X-OpenSNAP-Voucher: <opaque-blob>
   • Server verifies voucher, then processes HTTP body.

4. Settlement

   • Off‑protocol via any adapter: blockchain, ILP, centralized ledger.

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Adoption Strategy

1. Protocol Agnostic
   • Define only the handshake; payment backends are adapters.
   • Encourage community to build Solana, Lightning, ILP, or JWT adapters.
2. Reference Implementations
   • server.py / client.py for play‑money prototyping.
   • Easy to extend: swap rfc.md and adapter code.
3. Community‑First
   • Open RFC (rfc.md) on GitHub for issues and PRs.
   • Target AI/agent ecosystems (LangChain, AutoGPT) with plugins.
4. Sandbox & SDKs
   • Public sandbox for testing without real funds.
   • Official client SDK that abstracts voucher plumbing.

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Quick Start

1. Clone Repo

   git clone https://github.com/cashputation/OpenSNAP.git
   cd protocol

2. Run Server

   pip install fastapi uvicorn
   python3 server.py

3. Run Client

   pip install requests
   python3 client.py

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Resources

• RFC: rfc.md in this repo
• Issues: https://github.com/cashputation/OpenSNAP/protocol/issues
• Discussions: https://github.com/cashputation/OpenSNAP/protocol/discussions

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License

Apache 2.0 © OpenSNAP Contributors