# Hearth x402 API Discovery

> Hearth x402 API Discovery is a paid API for AI agents from 138-197-15-135.sslip.io, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).

Searches and ranks x402-compatible APIs by a plain-language task query, returning usage signals, pricing, and URLs for AI agent consumption

## Facts

- Endpoint: GET https://138-197-15-135.sslip.io/v1/x402/discover?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hearth-x402-api-discovery-81b62f3d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mYrePRitBUR7v8moWGQdB

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability hearth-x402-api-discovery-81b62f3d
```

Example prompt: Search Hearth for the top 5 x402 APIs that can help me do web search, on the Base network, with a max price of $0.02 per call.

## When to prefer this

Use this endpoint when an AI agent needs to dynamically discover which x402 pay-per-call APIs are available for a given task, especially when you want ranked results with real usage signals and price constraints. Prefer it over static API directories when you need live, usage-weighted rankings and want to filter by blockchain network or budget before committing a payment.

## Known failure modes

- Missing required 'q' query parameter returns a validation error
- No matching APIs found returns an empty results array
- Network filter with unsupported chain name may return zero results or an error
- maxPrice filter set too low may yield no results
- Malformed query parameters may cause a 400-level response
- x402 payment failure blocks access before the query is processed

## How this service works

x402 pay-safety precheck, ranked x402 API discovery, onchain (Base/EVM/Solana) data and web-to-Markdown for AI agents. Pay per call with x402 (USDC on Base).

## Output

A JSON object containing the original query string and an array of ranked API results, each with the endpoint URL, a qualitative usage signal (e.g. 'organic repeat usage'), price in USD per call, and 30-day usage stats including total calls, unique payers, and calls-per-payer ratio.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "queryParams"
   ],
   "properties": {
    "queryParams": {
     "type": "object",
     "required": [
      "q"
     ],
     "properties": {
      "n": {
       "type": "string",
       "description": "Results 1-10 (default 5)"
      },
      "q": {
       "type": "string",
       "description": "Task in plain words"
      },
      "network": {
       "type": "string",
       "description": "base, solana, polygon…"
      },
      "maxPrice": {
       "type": "string",
       "description": "Max price per call in USD"
      }
     }
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [],
     "properties": {
      "q": {
       "type": [
        "string",
        "null"
       ]
      },
      "results": {
       "type": [
        "array",
        "null"
       ]
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "q": "web search",
  "results": [
   {
    "url": "https://…/search",
    "signal": "organic repeat usage",
    "priceUsd": 0.01,
    "usage30d": {
     "calls": 4000,
     "payers": 120,
     "callsPerPayer": 33.3
    }
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hearth-x402-api-discovery-81b62f3d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 138-197-15-135.sslip.io](https://www.zero.xyz/host/138-197-15-135.sslip.io/llms.txt)