# APIHub.io

> The marketplace for AI agent APIs. Discover, pay for, and consume APIs with a single integration.

## What is APIHub?

APIHub is a marketplace where AI agents discover and pay for APIs using x402 (USDC on Base) for per-request on-chain payments. Agents connect via MCP (Model Context Protocol) or REST API. No pre-funding, no credit cards, no human approval required.

## Autonomous Registration

Agents can self-register without human intervention:
1. GET /v1/register/challenge - get the message to sign
2. Sign the message with your EVM wallet (personal_sign)
3. POST /v1/register with wallet_address and signature
4. Receive an API key immediately

No email or human approval required. The wallet IS your identity.

## Command-Line Interface

The fastest way to use APIHub from a terminal or AI coding tool:

```
npm install -g @apihubio/cli
# or run on-demand
npx @apihubio/cli <command>
```

Commands:
- apihub register - Sign up and save API key
- apihub balance - Show credit balance
- apihub topup <usd> - Buy credits (minimum $5)
- apihub search [query] - Search the marketplace
- apihub call <url> - Make a paid call through APIHub's proxy
- apihub add <url> - Save an x402 service to your toolset
- apihub install - Wire up MCP config for Claude/Cursor/Codex/Claude Code

npm: https://www.npmjs.com/package/@apihubio/cli

## API Endpoints

Base URL: https://api.apihub.io

Registration (no auth):
- GET /v1/register/challenge - get wallet signature challenge
- POST /v1/register - register with wallet signature, receive API key

Public (no auth):
- GET /v1/services - List all active native services (paginated)
- GET /v1/services/:slug - Get service details with endpoints
- GET /v1/external - List external x402 marketplace services
- GET /v1/external/:id - Get external listing with all endpoints

Authenticated (Bearer token):
- POST /v1/search - Search APIs by capability, category, or price
- GET /v1/wallet/balance - Check credit balance, spending history, and rate limits
- POST /v1/credits/purchase - Purchase credits via x402 payment
- GET /v1/credits/balance - Check credit balance
- GET /v1/credits/history - Credit transaction history

MCP (Bearer token):
- POST /mcp - MCP JSON-RPC endpoint (initialize, tools/list, tools/call)

Proxy (Bearer token):
- ANY /:service/:endpoint - Call native APIHub services
- POST /external { url, method, body, headers } - Call any external x402 API; APIHub pays provider from platform wallet, debits your credit balance for exact amount

## Authentication

All endpoints (except registration, /v1/external, and health) require a Bearer token:
Authorization: Bearer ahk_your_api_key

## MCP Server

URL: https://mcp.apihub.io/mcp

Tools:
- apihub_search - Find native APIs by capability, category, or price
- apihub_list_services - Browse all available native services
- apihub_get_service - Get full service details including schemas
- apihub_call - Make a paid API call to a native service
- apihub_search_external - Search external x402 marketplace services
- apihub_call_external - Call any external x402 URL via APIHub's proxy (credits pay provider, no wallet needed)
- apihub_read_content - Read web content through a paid content gateway
- apihub_topup - Purchase credits via x402 (USDC on Base). Returns payment instructions for browser, CLI, or direct x402
- apihub_balance - Check credit balance, spending, and rate limits

## Content Gateway

APIHub also supports content gateway services. Content creators register their domains and set per-page pricing. Agents access content via:
- GET /{service_slug}/fetch?url={target_url}

The proxy extracts clean structured content (title, text, headings) via headless browser rendering. Content services appear alongside API services in search and marketplace results.

## External APIs

The marketplace also includes external x402-compatible APIs discovered from public on-chain records. These are not operated by APIHub. Two ways to call external APIs:

1. Via APIHub (recommended): POST https://proxy.apihub.io/external or use apihub_call_external MCP tool. APIHub pays the provider on your behalf using the platform wallet; your credit balance is debited for the exact paid amount. No wallet or gas required.
2. Via direct x402: call the URL yourself with @x402/fetch and your own EVM wallet.

External APIs:
- Are monitored for uptime by APIHub
- Are marked with an "external" badge in the marketplace
- Link to a detail page with endpoint, pricing, schemas, and code examples

## Payments

For APIHub-native APIs, payment priority: free tier > prepaid credits > per-request x402 > 402 challenge.
For external APIs: x402 direct payment only.

1. Prepaid credits (native APIs only): Purchase credits via POST /v1/credits/purchase (single USDC transaction on Base). Each API call debits from your credit balance with no gas cost.
2. Per-request x402: USDC on Base via @x402/fetch client. Works for both native and external APIs.

## Rate Limits

- Free tier: 100 requests per minute per API key
- Paid tier (credit balance > 0): 1,000 requests per minute per API key
- Custom: contact us for higher limits

## Pricing

Providers set per-request prices in microdollars (1 USD = 1,000,000 microdollars).
Platform commission: 10% default, configurable per provider and per service.

## Links

- Website: https://apihub.io
- Full API Documentation: https://apihub.io/llms-full.txt
- API: https://api.apihub.io
- MCP: https://mcp.apihub.io/mcp
- Proxy: https://proxy.apihub.io
- Marketplace: https://apihub.io/marketplace
- Docs: https://apihub.io/docs
- Getting Started: https://apihub.io/docs/getting-started
- Agent Card: https://apihub.io/.well-known/agent.json
- Agent Skills: https://apihub.io/.well-known/agent-skills/index.json
- Agent Signup (human): https://apihub.io/agents/login

## Skills (step-by-step guides)

- Register: https://apihub.io/skills/register.md
- Purchase Credits: https://apihub.io/skills/purchase-credits.md
- Make an API Call: https://apihub.io/skills/make-api-call.md
- Handle 402 Responses: https://apihub.io/skills/handle-402.md
- Use MCP: https://apihub.io/skills/use-mcp.md
- Manage Balance: https://apihub.io/skills/manage-balance.md