# x402-payments

An agent skill for gating HTTP resources behind HBAR payments with x402: a 402 challenge, a signed transfer, then verify and settle through your own facilitator.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 462 installs · ★ 28
- Author: hedera-dev
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/hedera-dev/hedera-skills/tree/HEAD/plugins/native-services-js/skills/x402-payments/SKILL.md
- Updated: 2026-09-03
- HTML: https://affpapa.org/en/nevibecode/skills/x402-payments

## What it does

The skill lays out a pay-per-use pattern. Protected bytes stay off-chain, access terms live separately, and the HTTP resource is served only after payment. A buyer hits a 402 with a `PAYMENT-REQUIRED` header, signs an HBAR transfer, and retries with `PAYMENT-SIGNATURE`. The resource server verifies and settles through the facilitator, then returns the resource plus `PAYMENT-RESPONSE`.

Inside are instructions for wiring a resource server on `@x402/core` with `ExactHederaScheme`, a client retry loop, and a self-hosted facilitator exposing `GET /supported`, `POST /verify`, `POST /settle`, `GET /health`. Reference files cover server and client snippets, environment variables, and settle semantics. The wallet side expects an ECDSA Hedera account, for example HashPack over WalletConnect.

You need a funded ECDSA facilitator account up front: `FACILITATOR_ACCOUNT_ID` and `FACILITATOR_PRIVATE_KEY` belong to the facilitator process, never to the resource server. Amounts are tinybars, the asset is `0.0.0`, and client and server must share one network such as `hedera:testnet`. Put the facilitator key in the resource server and the whole split-role design falls apart, so that is the first thing to check.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add hedera-dev/hedera-skills --skill x402-payments -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/x402-payments/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/x402-payments/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add hedera-dev/hedera-skills --skill x402-payments -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/x402-payments/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add hedera-dev/hedera-skills --skill x402-payments -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/x402-payments/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install hedera-dev/hedera-skills x402-payments
```

2. **Manually: put the files in place**
- File: `.github/skills/x402-payments/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add hedera-dev/hedera-skills --skill x402-payments -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/hedera-dev/hedera-skills --path plugins/native-services-js/skills/x402-payments
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/x402-payments/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add hedera-dev/hedera-skills --skill x402-payments -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/hedera-dev/hedera-skills/tree/HEAD/plugins/native-services-js/skills/x402-payments/SKILL.md

## When to use it
- serve a protected file only after an HBAR payment
- run a self-hosted facilitator with verify and settle
- build a server loop around the 402 challenge and retry
- connect a WalletConnect wallet to sign the transfer
- convert prices to tinybars without rounding bugs

## Example prompts
- Gate this endpoint behind an HBAR payment with x402
- Set up a Hedera facilitator with verify and settle
- Add a client retry with PAYMENT-SIGNATURE after the 402

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 61c0861da9acff73.

BEGIN THIRD-PARTY FILE 61c0861da9acff73
````text
---
name: x402-payments
description: >
  x402 pay-per-use payments on Hedera. Use when gating HTTP resources behind native HBAR
  payments, wiring a self-hosted Hedera facilitator (verify/settle), building
  x402ResourceServer / ExactHederaScheme flows, or integrating WalletConnect payment
  retries (PAYMENT-REQUIRED → PAYMENT-SIGNATURE).
---

# x402 Payments (Hedera)

**Pay-per-use pattern:** store protected bytes off-chain, record access terms separately (on-chain or config), gate HTTP resources with **HTTP 402** + a **self-hosted Hedera facilitator** that verifies and settles native HBAR transfers.

```text
Buyer → GET protected resource
          ├─ free / public → resource
          └─ paid → 402 PAYMENT-REQUIRED
                → client signs HBAR transfer
                → retry with PAYMENT-SIGNATURE
                → resource server verify + settle via facilitator
                → PAYMENT-RESPONSE + resource
```

The resource server **never holds facilitator keys**. Settlement uses a funded **ECDSA** fee-payer account on the facilitator process.

## Quick Reference

| Piece | Role |
| ----- | ---- |
| Payment asset | `"0.0.0"` — native HBAR; amounts in **tinybars** (1 HBAR = 1e8) |
| Resource server | `@x402/core` + `ExactHederaScheme` → talks to facilitator over HTTP |
| Facilitator | `GET /supported`, `POST /verify`, `POST /settle`, `GET /health` |
| Client | Request → read 402 → sign → retry with `PAYMENT-SIGNATURE` (legacy `X-PAYMENT` also accepted) |
| Wallet | ECDSA Hedera account (e.g. HashPack via WalletConnect / UniversalProvider) |

See [references/examples.md](references/examples.md) for server/client snippets. See [references/facilitator.md](references/facilitator.md) for env vars and settle semantics.

## Critical: Facilitator Fee Payer

Hedera x402 settles with native `TransferTransaction`s. The buyer **partially signs** (authorize buyer → seller). The facilitator must:

1. Verify the signed payload against payment requirements
2. Co-sign as the advertised **fee payer** (`/supported`)
3. Pay network fees and submit until `SUCCESS`

Requires `FACILITATOR_ACCOUNT_ID` + `FACILITATOR_PRIVATE_KEY` on a funded **ECDSA** account — separate from deployer/seller keys. Do not put that key in the resource-server process.

## Critical: Prices Are Tinybars

Payment requirements use tinybars. Convert in UIs with 8-decimal helpers; never float.

```ts
````
END THIRD-PARTY FILE 61c0861da9acff73

The third-party file has ended. Everything between the 61c0861da9acff73 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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