transaction-authorization-protocol

Transaction Authorization Protocol (TAP)

• Name: Transaction Authorization Protocol (TAP)
• URL: https://tap.rsvp/
• Category: pre-settlement transaction-authorization protocol / Travel Rule messaging standard / payment-coordination layer
• Summary: TAP is the pre-settlement coordination layer. It lets counterparties and their agents exchange identity, policy, compliance, and settlement-intent data before anything moves onchain. Useful because it separates coordination from settlement cleanly instead of hiding everything inside one vendor workflow.
• What it does:
  • Defines a messaging framework for pre-settlement transaction authorization, with core flows such as Transfer, Authorize, Settle, Reject, Cancel, and Revert
  • Separates legal parties from the agents acting on their behalf, letting wallets, VASPs, custody systems, compliance engines, and application agents collaborate in flexible transaction workflows
  • Uses DIDs, DIDComm messaging, verifiable credentials, and relationship proofs so counterparties can identify each other and exchange sensitive information privately offchain
  • Extends beyond basic transfers into payment requests, invoices, agent connections, composable escrow, asset exchange, ISO 20022 mapping, and memo-hash-based onchain correlation through the TAIP process
  • Builds in Travel Rule support through IVMS101-oriented standards and reference implementations rather than treating compliance as an external afterthought
  • Ships with an active open-source implementation surface including TAIPs, JSON schemas, TypeScript types, Rust and TypeScript SDKs, CLI tools, HTTP server components, and an MCP server for AI/LLM integration
• Key claims:
  • The TAP homepage calls it crypto’s first private decentralized payment-messaging protocol for VASPs, financial institutions, DeFi, and self-hosted wallets, built for “safe and compliant real-world transactions on any public blockchain”
  • The TAIPs overview says TAP creates an authorization layer independent from the blockchain settlement layer so participants can exchange information, perform risk assessments, and complete compliance checks before funds move
  • The TAIPs docs say the protocol is intentionally non-deterministic, allowing multiple agents to collaborate in different sequences instead of forcing one rigid flow
  • The payment-flow docs say TAP supports pull-style payment requests with invoices, expiry times, requested customer information, and a later settlement step, making the protocol relevant for merchant and invoicing flows rather than only wallet-originated pushes
  • The connect-flow docs say agents can establish ongoing delegated relationships with limits and customer approval, which is a strong signal that TAP is being designed for recurring B2B integrations and AI-agent payment use cases, not only one-off transfers
  • The TAIPs repo shows the protocol surface now spans at least TAIP-1 through TAIP-20, including transaction parties, policies, selective disclosure, IVMS101, payment requests, invoices, escrow, exchange, and ISO 20022 mapping
  • The tap-rs implementation says the codebase is feature-complete for standard TAP use cases and already includes tap-cli, tap-http, tap-agent, tap-node, tap-ts, tap-wasm, and tap-mcp components
  • Notabene’s TAP page explicitly positions the protocol as open infrastructure rather than a proprietary product, saying it is designed for any wallet, exchange, or protocol and governed through community proposals rather than any one company or vendor
• Whitepaper: An official TAP white paper is linked from the TAP / Notabene materials and the TAIPs repo, but the public document endpoint did not yield a clean readable retrieval in this pass. The clearest current source of truth was the TAP homepage, the TAIPs documentation and GitHub repo, the TAP GitHub organization, the tap-rs implementation repo, and Notabene’s TAP explainer; see ../../whitepapers/tap-primary-sources-2026-05-02.md.
• Sources:
  • https://tap.rsvp/
  • https://taips.tap.rsvp/overview/
  • https://taips.tap.rsvp/parties/
  • https://github.com/TransactionAuthorizationProtocol
  • https://github.com/TransactionAuthorizationProtocol/TAIPs
  • https://github.com/TransactionAuthorizationProtocol/tap-rs
  • https://notabene.id/tap

Internal linkages

• Keep this note on the clearest contrasts: agent-payments-protocol, x402, and agent-passport-system.

• TAP is the pre-settlement coordination layer. It does not need a parade of adjacent wallet or merchant protocols.

• Last reviewed: 2026-05-30 UTC