docs: add MPP (Machine Payments Protocol) page + surface MPP/x402

build-on-celo/build-with-ai/8004.mdx

@@ -273,5 +273,6 @@ ERC-8004 works seamlessly with Celo's ecosystem:
 ## Related Protocols
 
 - [x402](/build-on-celo/build-with-ai/x402) - Payment layer for AI agents
+- [MPP](/build-on-celo/build-with-ai/mpp) - Machine Payments Protocol: charge USDC per request over HTTP
 - [Celopedia](/build-on-celo/build-with-ai/celopedia) - Celo ecosystem knowledge for coding assistants
 - [MCP Servers](/build-on-celo/build-with-ai/mcp/index) - Connect agents to data and tools

build-on-celo/build-with-ai/mpp.mdx

@@ -0,0 +1,169 @@
+---
+title: "MPP: Machine Payments Protocol"
+sidebarTitle: "MPP: Payments"
+---
+
+The **Machine Payments Protocol (MPP)** is an open standard for HTTP-native payments — it gives meaning to the HTTP `402 Payment Required` status code so that agents, apps, and services can pay each other for API access in a single request, with no accounts, invoices, or checkout flows.
+
+On Celo, MPP lets any service charge **USDC** per request. The buyer pays **no gas** — settlement is handled on-chain by a hosted facilitator.
+
+## How it works
+
+A request with no payment gets a `402` carrying an MPP **Challenge**. The buyer signs a **Credential** and retries; the server settles the payment on Celo and returns a **Receipt** with the on-chain transaction.
+
+```mermaid
+sequenceDiagram
+    participant Buyer as Buyer (agent/app)
+    participant Seller as Your API
+    participant Facilitator as Facilitator
+    participant Chain as Celo
+
+    Buyer->>Seller: 1. GET /premium (no payment)
+    Seller-->>Buyer: 2. 402 + WWW-Authenticate: Payment (challenge)
+    Buyer->>Buyer: 3. Sign credential (EIP-3009, no gas)
+    Buyer->>Seller: 4. Retry with Authorization (credential)
+    Seller->>Facilitator: 5. Settle
+    Facilitator->>Chain: 6. Submit USDC transfer, pay gas
+    Chain-->>Facilitator: 7. Confirmed
+    Facilitator-->>Seller: 8. Settlement reference
+    Seller-->>Buyer: 9. 200 + Payment-Receipt (tx hash)
+```
+
+USDC moves buyer → seller directly inside the token contract. The facilitator
+submits the transaction and pays the gas; it never custodies funds.
+
+## Prerequisites
+
+Settlement runs through a hosted facilitator that charges a small credit per
+transaction. Get an API key (a human does this once):
+
+1. Open [x402.celo.org](https://x402.celo.org) and connect an EVM wallet.
+2. Click **Create API key** and sign the message (no gas, no transaction).
+3. Copy the key (shown once) — it looks like `x402_...`.
+4. Set it as `X402_API_KEY` in your project.
+
+New accounts start with free testnet and mainnet credits. Develop on **Celo
+Sepolia** first.
+
+## Build with MPP
+
+Install the [`mppx`](https://www.npmjs.com/package/mppx) SDK.
+
+```bash
+npm i mppx @hono/node-server hono viem
+```
+
+### Seller — charge for your API
+
+Configure MPP with one payment method — a one-time EVM charge on Celo — and
+settle through the Celo facilitator. Passing the known asset
+(`assets.celoSepolia.USDC`) lets `mppx` infer the chain id, decimals, and EIP-712
+domain for you.
+
+```ts
+import { serve } from "@hono/node-server";
+import { Hono } from "hono";
+import { Mppx } from "mppx/server";
+import { evm, assets } from "mppx/evm/server";
+
+// Attach the facilitator API key to every settlement request.
+const apiKeyFetch: typeof fetch = (input, init = {}) => {
+  const headers = new Headers(init.headers);
+  headers.set("X-API-Key", process.env.X402_API_KEY!);
+  return fetch(input, { ...init, headers });
+};
+
+const mppx = Mppx.create({
+  methods: [
+    evm.charge({
+      currency: assets.celoSepolia.USDC, // Celo Sepolia (mainnet: assets.celo.USDC)
+      recipient: process.env.SELLER_PAY_TO as `0x${string}`, // your receiving wallet
+      x402: {
+        facilitator: "https://api.x402.sepolia.celo.org", // mainnet: https://api.x402.celo.org
+        fetch: apiKeyFetch,
+      },
+    }),
+  ],
+  secretKey: process.env.MPP_SECRET_KEY!, // openssl rand -base64 32
+});
+
+const app = new Hono();
+app.get("/premium", async (c) => {
+  const result = await mppx.charge({ amount: "0.01" })(c.req.raw); // $0.01
+  if (result.status === 402) return result.challenge;
+  return result.withReceipt(Response.json({ data: "this response cost $0.01" }));
+});
+
+serve({ fetch: app.fetch, port: 3402 });
+```
+
+### Buyer — pay automatically
+
+The `mppx` client patches `fetch` to answer MPP challenges automatically. The
+buyer needs a wallet funded with USDC and **no** native gas.
+
+```ts
+import { privateKeyToAccount } from "viem/accounts";
+import { Mppx } from "mppx/client";
+import { evm } from "mppx/evm/client";
+
+const account = privateKeyToAccount(process.env.BUYER_PRIVATE_KEY as `0x${string}`);
+
+Mppx.create({
+  methods: [
+    evm.charge({
+      account,
+      networks: [11142220], // Celo Sepolia (mainnet: 42220)
+      currencies: ["0x01C5C0122039549AD1493B8220cABEdD739BC44E"], // Celo Sepolia USDC
+      decimals: 6,
+      authorization: { name: "USDC", version: "2" }, // Celo USDC EIP-712 domain
+      maxAmount: "1", // never pay more than 1 USDC per request
+    }),
+  ],
+});
+
+// Global fetch now pays MPP-gated endpoints automatically.
+const res = await fetch("http://localhost:3402/premium");
+console.log(res.status, await res.json()); // 200, your paid content
+```
+
+<Note>
+  On the **buyer** side you must supply the token `decimals` and its EIP-712
+  `authorization` (`{ name, version }`) — the client builds the payment
+  credential locally and does not read these from the server's challenge. For
+  Celo USDC the domain is `name: "USDC"`, `version: "2"`.
+</Note>
+
+## Example project
+
+A complete, runnable seller + buyer you can clone and run in minutes — verified
+end-to-end on Celo testnet and mainnet:
+
+<Card title="celo-org/mpp-celo-example" icon="github" href="https://github.com/celo-org/mpp-celo-example">
+  Minimal MPP example on Celo — a paid API and a client that pays it.
+</Card>
+
+```bash
+git clone https://github.com/celo-org/mpp-celo-example
+cd mpp-celo-example
+npm install
+cp .env.example .env   # add MPP_SECRET_KEY, X402_API_KEY, SELLER_PAY_TO, BUYER_PRIVATE_KEY
+npm run seller         # terminal 1
+npm run buyer          # terminal 2 — pays and prints the settlement tx
+```
+
+## Supported assets on Celo
+
+| Token | Network | Address |
+|-------|---------|---------|
+| USDC | Celo mainnet | `0xcebA9300f2b948710d2653dD7B07f33A8B32118C` |
+| USDC | Celo Sepolia | `0x01C5C0122039549AD1493B8220cABEdD739BC44E` |
+
+Both are 6-decimal and support gasless EIP-3009 transfers.
+
+## Resources
+
+- MPP protocol: [mpp.dev](https://mpp.dev)
+- `mppx` SDK: [npmjs.com/package/mppx](https://www.npmjs.com/package/mppx)
+- Facilitator dashboard (API key + credits): [x402.celo.org](https://x402.celo.org)
+- Example repo: [celo-org/mpp-celo-example](https://github.com/celo-org/mpp-celo-example)

build-on-celo/build-with-ai/overview.mdx

@@ -7,7 +7,7 @@ sidebarTitle: "Overview"
 
 Celo is a leading Ethereum Layer 2 optimized for agentic activity with real-world utility, enabling AI agents to autonomously perform onchain actions tied directly to payments, commerce, and financial coordination.
 
-Agents on Celo can tap into the network's expansive payments ecosystem, leveraging fast finality, sub-cent transaction costs, and a stablecoin-optimized financial stack spanning peer-to-peer transfers, merchant payments, remittances, and onchain FX. Combined with native support for AI agent standards like [ERC-8004](/build-on-celo/build-with-ai/8004) and Celo's [Celopedia](/build-on-celo/build-with-ai/celopedia), Celo provides a production-ready environment for deploying AI agents that do more than trade tokens—they move money, coordinate economic activity, and interact with real users at global scale.
+Agents on Celo can tap into the network's expansive payments ecosystem, leveraging fast finality, sub-cent transaction costs, and a stablecoin-optimized financial stack spanning peer-to-peer transfers, merchant payments, remittances, and onchain FX. Combined with native support for agent standards like [ERC-8004](/build-on-celo/build-with-ai/8004) for trust, [x402](/build-on-celo/build-with-ai/x402) and [MPP](/build-on-celo/build-with-ai/mpp) for HTTP-native payments, and Celo's [Celopedia](/build-on-celo/build-with-ai/celopedia), Celo provides a production-ready environment for deploying AI agents that do more than trade tokens—they move money, coordinate economic activity, and interact with real users at global scale.
 
 ## Why Build AI Agents on Celo
 
@@ -51,6 +51,15 @@ On Celo, agents are first-class participants in the economy. They can send and r
 - Collaborative systems where agents work together.
 - Examples: Collective problem-solving, distributed decision-making, or agent-to-agent communication.
 
+## Agent Payments with x402 and MPP
+
+Agents on Celo can charge and pay for services over plain HTTP, settling in stablecoins in a single request — no accounts, invoices, or checkout flows.
+
+- **[x402](/build-on-celo/build-with-ai/x402)** gives meaning to the HTTP `402 Payment Required` status code, letting an agent settle a stablecoin micropayment inline with the request.
+- **[MPP (Machine Payments Protocol)](/build-on-celo/build-with-ai/mpp)** builds on the same flow so any service can charge USDC per request through a hosted facilitator — the buyer pays no gas.
+
+Both settle on-chain in seconds, making them well-suited to paid APIs, pay-per-use tools, and agent-to-agent commerce.
+
 ## Fee Abstraction for Agents
 
 AI agents on Celo can pay gas fees in stablecoins like USDC or USDT instead of needing a separate CELO balance. This simplifies agent treasury management to a single token — the same stablecoin the agent already holds for payments and settlements.

build-on-celo/build-with-ai/x402.mdx

@@ -394,6 +394,7 @@ app.get("/articles/:id", async (req, res) => {
 ## Related
 
 - [ERC-8004](/build-on-celo/build-with-ai/8004) - Trust layer for AI agents
+- [MPP](/build-on-celo/build-with-ai/mpp) - Machine Payments Protocol: charge USDC per request over HTTP
 - [Celopedia](/build-on-celo/build-with-ai/celopedia) - Celo ecosystem knowledge for coding assistants
 - [Fee Abstraction](/build-on-celo/fee-abstraction/overview) - Pay gas with stablecoins on Celo
 - [Attribution Tags](/build-on-celo/attribution-tags) - Credit on-chain activity back to your app

docs.json

@@ -133,6 +133,7 @@
                 "pages": [
                   "build-on-celo/build-with-ai/8004",
                   "build-on-celo/build-with-ai/x402",
+                  "build-on-celo/build-with-ai/mpp",
                   "build-on-celo/build-with-ai/celopedia",
                   "build-on-celo/build-with-ai/vibe-coding"
                 ]

home/celo.mdx

@@ -35,6 +35,9 @@ description: "Celo is a leading Ethereum L2. As the frontier chain for global im
   <Card title="x402: Agent Payments" icon="money-bill-transfer" href="/build-on-celo/build-with-ai/x402">
     Enable instant, permissionless micropayments for AI agents using stablecoins via HTTP 402.
   </Card>
+  <Card title="MPP: Machine Payments" icon="credit-card" href="/build-on-celo/build-with-ai/mpp">
+    Charge USDC per API request over HTTP — gasless for the buyer, settled on-chain via a hosted facilitator.
+  </Card>
 </CardGroup>
 
 ## Builder Support