What to know:
- Proof has introduced x401 to verify human authorization behind AI agent actions using trusted digital credentials.
- x401 protects privacy through selective disclosure and zero-knowledge proofs during identity verification.
- The protocol works with x402 to combine identity verification and machine payments for agentic workflows.
Proof has introduced the x401 protocol, a new identity authorization protocol designed to verify the people behind AI-generated actions. The launch matters because organizations increasingly rely on AI agents to complete digital tasks.
Proof focuses on confirming human authorization rather than verifying the AI itself. The company has secured more than $640 billion in transactions for 10,000 organizations, including 16 Fortune 100 companies.
Source: Proof
The protocol uses HTTP 401-style challenges instead of traditional usernames and passwords. AI agents respond with cryptographically signed verifiable credentials that support selective disclosure and zero-knowledge proofs.
This approach allows users to prove eligibility, such as age or residency, without exposing unnecessary personal information. That reduces data sharing while maintaining trusted identity verification.
“AI is making actions and content effortless to generate. Trust will come from knowing who stands behind them. x401 gives every service a common way to ask for proof. Proof Digital ID gives people and organizations a high-assurance signed record of who authorized what.” – Pat Kinsel, CEO of Proof.
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Proof Launches x401 Protocol for AI Identity Verification
According to Proof, the initial release is functioning using its digital identity and cloud wallet. The live demo and technical documents for developers have been released. It allows companies to review the protocol before rolling it out on a wider scale.
Furthermore, the company has also provided the entire specification and contributors’ list for developers to get details about the implementation.
The protocol works alongside other systems that enable the performance of actions by AI. The protocol x402 allows making payments, while AP2 and verifiable intent track orders and confirmations.
The x401 Protocol fills the last gap by proving the identity of the individual behind each action. Together, these make a more comprehensive system that can be built for performing AI transactions.
x401 Expands AI Identity With Industry Support
Circle, OpenAI, Google, and Okta have been involved in building the x401 protocol. Their participation demonstrates increasing industry attention toward developing open standards for identity in AI platforms.
According to Proof, their partnership with Circle brings together identification and the payment feature of x402. Together, they answer two key questions when dealing with agentic transactions: Who authorized the transaction, and how are payments made?
Proof became a Sponsor member of the FIDO Alliance in May 2026. The protocol remains issuer-neutral and works with government ID cards, company badge IDs, and self-sovereign identities on one platform.
This makes for a broad range of use cases because companies do not need to replace their current verification system.
Proof has released the x401 protocol’s specification, technical documentation, application examples, and the list of contributors to help developers. Companies may now use the live x401 MCP server along with Claude and ChatGPT to test the protocol in real-world scenarios.
What Happens Next for x401 Adoption?
The versatility of the x401 protocol opens up many different applications within banks, payment processors, businesses, governments, healthcare, SaaS companies, and AI researchers.
It does not replace existing identity infrastructure but rather supplements it with cryptographic proof of authorization. Proof has made available the x401 specifications, documentation, sample implementations, and a working MCP server.
The next step involves adoption by enterprises as they implement the x401 protocol in their AI assistants, payment services, and business software.
The x401 may become an everyday authorization mechanism used by autonomous AI services, but its sustained success will depend on widespread endorsement by identity providers, banks, enterprises, and software providers.
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