TAP (Transaction Authorization Protocol)
The open protocol for
trusted blockchain payments
Transaction Authorization Protocol is a public protocol for authorizing blockchain payments before settlement. It’s designed for any wallet, exchange, or protocol—not tied to any single platform or company.
How TAP authorizes before funds move
TAP starts with a Transfer Request—signed and shared before any transaction hits the blockchain. Agents coordinate via DIDComm, validate policies, and authorize flows. Only then does the transaction settle on-chain—on whichever network the parties choose.
Blockchains weren’t built for business payments
Most crypto payments are authorized by the sender alone—without coordination from the recipient or other intermediaries. That doesn’t work for B2B or institutional payments, where multiple parties need to verify and authorize a transaction before funds move.
An open protocol for pre-settlement authorization
The Transaction Authorization Protocol (TAP) defines how counterparties coordinate authorization before a blockchain transaction settles—across any platform or network. It uses signed Transfer Requests and encrypted messaging to authorize payments securely across wallets, exchanges, and smart contracts.
Parties
Real-world actors like merchants or exchanges
Agents
Systems (wallets, smart contracts, etc.) acting on their behalf
Policies
Programmable rules for compliance and trust
Messaging
Secure DIDComm communication across participants
Built for real-world payment flows
Whether you're building a global exchange, managing risk at a bank, or designing new payment flows, Notabene Transact helps your team move faster, stay compliant, and scale securely.
B2B Payments
Pre-settlement verification of counterparties, authorization flows across institutions
E-Commerce Merchants
TAP enables programmable receipt logic and refund prevention
DeFi Protocols
TAP lets protocols wait for external authorization before execution
For infrastructure teams solving coordination at scale
Orchestrators & Payment Networks
Implementing crypto payment flows across existing systems.
Our Solution with TAP:
Integrates with existing workflows and supports policy customization.
Wallet Providers
Building custody tools that need authorization flows before transaction execution.
Our Solution with TAP:
Enables DID-based coordination while preserving user control.
Exchanges & Custodians
Running multi-party flows with complex compliance needs.
Our Solution with TAP:
Standardizes authorization without delaying throughput.
Fintech Platforms & PSPs
Implementing crypto payment flows across existing systems.
Our Solution with TAP:
Integrates with existing workflows and supports policy customization.
Regulators & Banks
Demanding visibility and auditability in crypto payments.
Our Solution with TAP:
Provides traceability, pre-settlement logic, and compliance assurance.
Developer-led evolution through TAIPs
TAP evolves through TAIPs—Transaction Authorization Improvement Proposals. Anyone can propose new message types, policy logic, or technical extensions. This open governance model ensures TAP adapts with the needs of its users, not the dictates of a single vendor.
Open by design
TAP is open infrastructure—not a product. It’s maintained by contributors from across the crypto and finance ecosystem. Governance happens through community proposals—not through any one company or vendor.
Works across blockchains
Open-source
Ecosystem-governed
Build with TAP
Ready to bring trust to the next wave of blockchain payments? Start building with TAP today.