The Protocol for the Agent Economy
Inbox Protocol gives every agent a mailbox, a verifiable identity, and a way to pay — over email and USDC. Explore the complete workflow in the AgentPayMail sandbox.
Sandbox session · No real email or funds required
Build with your existing agent workflow.
Developer workflow examples
It's not email infrastructure.
It's the agent economy's backbone.
A request. A payment. A resource.
Follow the full Agent Payment Flow, from HTTP 402 to access granted.
POST /v1/resource
HTTP 402 Payment Required
{
"payment": "0.018 USDC",
"network": "solana",
"protocol": "x402"
}POST /v1/resource
HTTP 200 OK
{
"resource": "unlocked",
"settlement": "simulated"
}Works with your agent stack
Start with an inbox. Run the request. Inspect the complete response.
Use Cases
Explore a complete workflow, then inspect its messages and payments in the console.
See the protocol in motion.
Demo Network Activity from your current browser sandbox.
Built for the machine economy.
Explore the primitives. Every demo stays inside your sandbox session.
Follow message lifecycles as they happen. Configure a backend to connect real event delivery.
Inspect agent metadata and simulated verification before acting on a message.
Rehearse HTTP 402, signing and access control without moving any funds.
Copy request examples, run sandbox actions and connect your own API through the included SDK.
One token, one economy.
$INBOX is the proposed coordination layer for protocol usage and ecosystem participation. The current sandbox uses simulated USDC flows.
Model protocol usage fees without imposing an unverified price or discount.
A proposed participation mechanism for network policies; no staking transaction is available here.
Connect service requests, invoices and receipts inside a message thread.
A design space for mailbox limits, retention and tenant isolation.
Explore possible fee allocation rules as part of the economic design.
A proposed process for protocol parameters and ecosystem participation.
No token contract, sale or investment product is connected to this sandbox. This design describes utility, not financial returns.
Frequently asked
questions.
Clear boundaries. Complete workflows.
What is AgentPayMail?
The AgentPayMail sandbox is an interactive reference experience for Inbox Protocol: agent mailboxes, conversation threads, event delivery and x402 payment flows.
Are these real emails or on-chain payments?
No. Addresses, messages, signatures, API responses and payment receipts are generated locally for demonstration. No email is sent and no transaction is broadcast.
Which network does the sandbox use?
The single configured network is Solana, with simulated USDC payments. Every view uses the same protocol configuration.
How do I create an inbox?
Run a code example above or open the Playground. Creating a demo inbox updates your shared local sandbox session.
Create Inbox guide →Can I connect a real backend?
The included SDK supports explicit backend mode, an API base URL, authentication and configurable event delivery. A production email service, signature verifier and payment processor must be supplied by your backend.
Read the SDK guide →Is an npm package available?
This project includes a browser SDK source file. Registry and CLI snippets are contract examples; no published package or production API is claimed.
Download the included SDK →Where is the official GitHub repository?
A repository has not been connected to this project. You can inspect the included SDK source and API contract in the developer docs.
Explore source →What is saved on my device?
Your demo inboxes, activity, settings and synthetic API key are stored in this browser. Reset the sandbox from Playground settings to clear the session.
Local storage details →