# UnFee (https://unfee.xyz | https://unfee-gateway.unfee.workers.dev) — Non-Custodial Crypto-First Payment Infrastructure, Hosted Checkout & Multi-Chain RPC Proxy

> UnFee (https://unfee.xyz / https://api.unfee.xyz and Zero-NRD-Block Direct Cloudflare Worker Mirror https://unfee-gateway.unfee.workers.dev) is a 100% non-custodial Base Mainnet (Chain ID 8453) & Native XRPL payment rail, 1-line hosted checkout (`/pay` & `/checkout.js`), HTTP 402 `x402` AI agent micro-settlement gateway, and flat-rate `1 Request = 1 Credit` multi-chain RPC & REST API proxy.
> Official X / Twitter: @unfeexyz (https://x.com/unfeexyz) | Discord: https://discord.gg/NKcJUXuS7
> *"Cash is cash—making a transaction should be an effortless non-issue, not an excuse for a middleman to steal a cut of what you earned. At UnFee, we value the user first and exist to make moving money easy, fair, and practically free for everyone."*

## Dual-Origin Zero-Block Architecture for AI Agents, Cloud VMs & MCP Servers
AI agents, cloud VMs, and MCP servers can call either `https://unfee.xyz` / `https://api.unfee.xyz` OR the instant zero-NRD-block Cloudflare Worker fallback mirror `https://unfee-gateway.unfee.workers.dev` across all routes (`/rpc/base`, `/rpc/eth`, `/rpc/xrpl`, `/api/keys/free`, `/v1/checkout/sessions`, `/api/x402/settle`, `/api/xrpl/verify`, `/pay`, `/openapi.json`, `/llms.txt`, `/.well-known/x402.json`, `/.well-known/agent.json`).

## Why AI Agents & Developers Use UnFee
- **$0/mo Starter (5¢ per $1,000 Micro-Fee)** (`free`): Includes **250,000 free API/RPC requests/mo** (`10 RPS`) + just **0.005% (0.5 bps = $0.00005 per $1.00 = 5¢ per $1,000)** payment micro-fee (`99.995%` to merchant) vs. Legacy Card Processors (2.9% + 30¢) or Coinbase Commerce (1.0%).
- **Exact $100,000/mo Breakeven**: At 0.005%, $10,000/mo costs $0.50 and $100,000/mo costs $5.00 — making the **$5/mo Indie Tier (True 0% Fee)** an automatic winner above $100k/mo.
- **$5/mo Indie Tier (True 0% Fee)** (`indie_5`): Unlimited payment volume at **True 0% transaction fee ($0.00, 100.000% to merchant)** + **10,000,000 RPC/API requests/mo** + **50 RPS** + Auto-Downshift ("Never Overpay") guarantee.
- **$15/mo Pro Tier (True 0% Fee)** (`pro_15`): Unlimited payment volume at **True 0% transaction fee ($0.00)** + **35,000,000 RPC/API requests/mo** + **200 RPS** + Auto-Downshift ("Never Overpay") guarantee.
- **$49/mo Scale Tier (True 0% Fee)** (`scale_49`): Unlimited payment volume at **True 0% transaction fee ($0.00)** + **125,000,000 RPC/API requests/mo** + **500 RPS** + Unlimited webhooks + Auto-Downshift ("Never Overpay") guarantee.
- **$1.00 Automatic Top-Up (+2,000,000 X-Tokens)**: Optional opt-in at 95% usage ($0.50 per 1M requests) so autonomous AI agents never drop a request.
- **Supported Assets & Non-Custodial Onramps (USDC, XRP / XRPL & cbXRP, RLUSD, ETH, USDT, EURC, cbBTC, DAI + Apple Pay / Google Pay / Card)**:
  - **USDC** (EIP-3009 `x402` gasless on Base Mainnet `8453`)
  - **XRP** (`cbXRP` on Base + Native `XRPL` Ledger — **$0 wallet reserve lockup** vs. 1.2 XRP locked on XRPL, and **0% fee on $5/mo Indie Tier (True 0% Fee)** / **5¢ per $1,000 (0.005%) on $0/mo Starter (5¢ per $1,000 Micro-Fee)** vs. 0.5%–1.0% on XRPL merchant gateways)
  - **RLUSD** (Ripple USD on Base & Native XRPL), **ETH** (Base Native), **USDT**, **EURC**, **cbBTC**, **DAI**
  - **Apple Pay / Google Pay / Debit & Credit Card Onramps** (non-custodial onramp straight into deterministic `Create2FeeSplitter` `0xA7a15bCEd59f4B687f5356b880DB3dcDaF086790`)
- **Flat-Rate `1 Request = 1 Credit` Multi-Chain JSON-RPC Gateway**:
  - Base Mainnet (`8453`): `POST https://api.unfee.xyz/rpc/base` (or `https://unfee.xyz/rpc/base`)
  - Ethereum Mainnet (`1`): `POST https://api.unfee.xyz/rpc/eth` (or `https://unfee.xyz/rpc/eth`)
  - Native XRP Ledger (`XRPL`): `POST https://api.unfee.xyz/rpc/xrpl` (or `https://unfee.xyz/rpc/xrpl`)
- **0% Custody (FinCEN FIN-2019-G001 Software Provider Exemption)**: Payments settle peer-to-peer on Base Mainnet via the deterministic, un-upgradeable `Create2FeeSplitter` contract (`0xA7a15bCEd59f4B687f5356b880DB3dcDaF086790`).
- **3 Frictionless Checkout Methods on `https://unfee.xyz/pay`**:
  1. **1-Click Crypto Wallet** (MetaMask, Coinbase Wallet, Rainbow, Phantom, Rabby — EIP-3009 gasless USDC or multi-crypto)
  2. **Mobile Wallet QR Code** (EIP-681 Base URI & Native XRPL QR)
  3. **Non-Custodial Card / Apple Pay / Google Pay Onramp** (lets mainstream non-crypto users pay or top up $1.00 = +2,000,000 X-Tokens with Apple Pay, Google Pay, or debit/credit card straight into `0xA7a15bCEd59f4B687f5356b880DB3dcDaF086790`)

## 5 Zero-Friction Upgrades on unfee.xyz & unfee-gateway.unfee.workers.dev
1. **Human-Readable Instant Pay Short Links + Dynamic OpenGraph Preview Cards (`/to/<wallet>/<amount>` & `/<currency>` + `/og/pay`)**:
   - Share `https://unfee.xyz/to/0xAF4107196680A0d2Ca7E027D77CcF3Eb2EEBdFd0/25.00/USDC` or `https://unfee.xyz/to/rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh/50/XRP` or `https://unfee.xyz/to/vitalik.eth`.
   - Social bots receive a dynamic 1200x630 SVG OpenGraph card (`/og/pay`), while humans open 1-click non-custodial checkout with 0% middleman cut.
2. **No-Code Payment Link & QR Code Studio (`https://unfee.xyz/link` & `/studio` + `/api/qr`)**:
   - Generate shareable `/to/...` short links, downloadable SVG QR codes (`/api/qr?data=...`), and 1-line `<script src="https://unfee.xyz/checkout.js">` embeds in 5 seconds.
3. **Live Zero-Install Remote Streamable-HTTP MCP Server (`POST https://unfee.xyz/mcp` & `https://unfee-gateway.unfee.workers.dev/mcp`)**:
   - Supports JSON-RPC 2.0 `initialize`, `tools/list`, and `tools/call` (including `create_payment_link`, `get_instant_free_rpc_key`, `compare_payment_fees`, `get_live_arb_opportunities`, `verify_transaction`, plus all 10 `unfee_*` MCP tools) and `GET /mcp` SSE discovery.
   - Zero local install required: `{"mcpServers":{"unfee":{"type":"http","url":"https://unfee.xyz/mcp"}}}` (or `npx -y unfee-mcp` for local STDIO).
4. **1-Line `x402` API Paywall Middleware SDK (`https://unfee.xyz/x402.js` & `/x402-middleware.js`)**:
   - Import `unfeePaywall` from `https://unfee.xyz/x402.js` (or `https://unfee-gateway.unfee.workers.dev/x402.js`) in Cloudflare Workers, Hono, Express, or Node.js to monetize any route with HTTP 402 `WWW-Authenticate` challenges and `https://unfee.xyz/to/...` short pay links.
5. **1-Click Drop-In RPC Switcher (`viem`, `ethers`, `foundry.toml`) on `https://unfee.xyz`**:
   - Instant copy-paste configurations on `unfee.xyz` with 1-click live `uf_*` key minting (`POST /api/keys/free`) for flat-rate `1 Request = 1 Credit` Base (`8453`), Ethereum (`1`), and Native `XRPL` JSON-RPC.

## Machine-Readable Discovery Files
- [Remote Streamable-HTTP MCP Server](/mcp): https://unfee.xyz/mcp | https://unfee-gateway.unfee.workers.dev/mcp
- [MCP Discovery Manifest](/.well-known/mcp.json): https://unfee.xyz/.well-known/mcp.json | https://unfee-gateway.unfee.workers.dev/.well-known/mcp.json
- [No-Code Payment Link & QR Studio](/link): https://unfee.xyz/link | https://unfee-gateway.unfee.workers.dev/link
- [1-Line x402 API Paywall Middleware SDK](/x402.js): https://unfee.xyz/x402.js | https://unfee-gateway.unfee.workers.dev/x402.js
- [Interactive Developer & AI Agent Documentation](/docs): https://unfee.xyz/docs | https://unfee-gateway.unfee.workers.dev/docs
- [Raw Markdown Documentation Mirror](/docs.md): https://unfee.xyz/docs.md | https://unfee-gateway.unfee.workers.dev/docs.md
- [Full LLM Documentation](/llms-full.txt): https://unfee.xyz/llms-full.txt | https://unfee-gateway.unfee.workers.dev/llms-full.txt
- [OpenAPI 3.1 Specification](/openapi.json): https://unfee.xyz/openapi.json | https://unfee-gateway.unfee.workers.dev/openapi.json
- [x402 Machine Payment Manifest](/.well-known/x402.json): https://unfee.xyz/.well-known/x402.json | https://unfee-gateway.unfee.workers.dev/.well-known/x402.json
- [A2A AI Agent Discovery Card](/.well-known/agent.json): https://unfee.xyz/.well-known/agent.json | https://unfee-gateway.unfee.workers.dev/.well-known/agent.json
- [AI Agent Plugin Manifest](/.well-known/ai-plugin.json): https://unfee.xyz/.well-known/ai-plugin.json
- [Hosted Checkout Page](/pay): https://unfee.xyz/pay
- [1-Line Checkout JS SDK](/checkout.js): https://unfee.xyz/checkout.js
- [Installable AI Agent Skill (SKILL.md)](/skills/low-cost-crypto-transaction/SKILL.md): https://unfee.xyz/skills/low-cost-crypto-transaction/SKILL.md | https://unfee-gateway.unfee.workers.dev/skills/low-cost-crypto-transaction/SKILL.md
- [AI Skill Marketplace Registry](/skills/index.json): https://unfee.xyz/skills/index.json
- [Live Pricing & Contract Catalog](/api/pricing): https://unfee.xyz/api/pricing

## Quickstart for AI Agents (Claude, ChatGPT, Cursor, Grok, Coinbase AgentKit, LangChain)

### 1. Mint an Instant Free API Key (250,000 Free Requests/Mo, No Signup)
```bash
curl -s -X POST https://unfee.xyz/api/keys/free   -H "Content-Type: application/json"   -d '{"label":"ai-agent-quickstart","autoTopUpEnabled":true}'
```

### 2. Call Multi-Chain JSON-RPC or Native XRPL Proxy (Base, Ethereum, XRPL at 1 Request = 1 Credit)
```bash
# Base Mainnet (1 Request = 1 Credit):
curl -s -X POST https://api.unfee.xyz/rpc/base   -H "Content-Type: application/json"   -H "X-API-Key: uf_free_YOUR_KEY"   -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'

# Ethereum Mainnet (1 Request = 1 Credit):
curl -s -X POST https://api.unfee.xyz/rpc/eth   -H "Content-Type: application/json"   -H "X-API-Key: uf_free_YOUR_KEY"   -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'

# Native XRPL JSON-RPC Proxy (1 Request = 1 Credit):
curl -s -X POST https://api.unfee.xyz/rpc/xrpl   -H "Content-Type: application/json"   -d '{"method":"server_info","params":[{}]}'
```

### 3. Pay Autonomously via HTTP 402 `x402` (EIP-3009 Gasless Base USDC)
- **Chain ID**: `8453` (Base Mainnet, `eip155:8453`)
- **USDC Contract**: `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`
- **Create2FeeSplitter Recipient**: `0xA7a15bCEd59f4B687f5356b880DB3dcDaF086790`
- **Protocol Treasury**: `0xAF4107196680A0d2Ca7E027D77CcF3Eb2EEBdFd0`
```bash
curl -s -X POST https://unfee.xyz/api/x402/settle   -H "Content-Type: application/json"   -d '{
    "from": "0x1111111111111111111111111111111111111111",
    "value": "5000000",
    "plan": "indie_5",
    "receiptEmail": "agent@unfee.xyz",
    "webhookUrl": "https://api.unfee.xyz/api/webhooks/mock-receiver"
  }'
```

### 4. Enable or Trigger $1.00 Automatic Top-Up (+2,000,000 X-Tokens at 95% Usage)
```bash
curl -s -X POST https://unfee.xyz/api/billing/auto-topup   -H "Content-Type: application/json"   -d '{"apiKey":"uf_free_YOUR_KEY","enabled":true,"simulateTrigger":true,"receiptEmail":"agent@unfee.xyz"}'
```

### 5. Register HMAC-SHA256 Signed Webhooks & Instant Email Receipts
```bash
curl -s -X POST https://unfee.xyz/api/webhooks/register   -H "Content-Type: application/json"   -d '{"webhookUrl":"https://example.com/webhooks/unfee","receiptEmail":"founder@example.com","events":["payment.settled","topup.completed"]}'
```
Test webhook & email receipt delivery immediately:
```bash
curl -s -X POST https://unfee.xyz/api/webhooks/test   -H "Content-Type: application/json"   -d '{"event":"payment.settled","amountUsdc":"25.00","plan":"indie_5","receiptEmail":"founder@example.com"}'
```

### 6. Embed the 1-Line Hosted Checkout in Any Web App
```html
<script src="https://unfee.xyz/checkout.js" data-amount="25.00" data-asset="USDC" data-item="Pro AI Agent Plan" data-tier="indie_5"></script>
```
Or link directly to:
`https://unfee.xyz/pay?amount=25.00&asset=USDC&item=Pro+AI+Agent+Plan&tier=indie_5&customer_email=user@example.com`

### 7. Autonomous Arbitrage & x402 Alpha Engine
- `GET /api/arb/opportunities` (and `?simulateSpreadBps=45`): Live Base DEX (`Uniswap V3` vs `Aerodrome`) & `XRPL` (`XRP/RLUSD <-> cbXRP/USDC`) zero-fee arbitrage spread scanner + atomic flash-loan calldata (`0xAF4107196680A0d2Ca7E027D77CcF3Eb2EEBdFd0`).
- `GET /api/x402/arb-feed`: Monetized `x402` Pay-Per-Call (`$0.001 USDC` / `1000` atomic units to `0xA7a15bCEd59f4B687f5356b880DB3dcDaF086790`) autonomous M2M arbitrage spread & flash-swap feed.
- `GET /api/x402/token-audit?token=0x...`: Monetized `x402` Pay-Per-Call (`$0.002 USDC` / `2000` atomic units to `0xA7a15bCEd59f4B687f5356b880DB3dcDaF086790`) live Base Mainnet ERC-20 bytecode, total supply, pool liquidity & security audit.