# x402engine — Pay-per-call APIs for AI Agents

> x402engine — Pay-per-call APIs for AI Agents is a paid API for AI agents from x402engine.app, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).

## Facts

- Endpoint: POST https://x402engine.app/api/transcribe
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-transcribe-3dd2487e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2h9e5dPIwPqLA9y8KnLeO

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 api-transcribe-3dd2487e -d '<json body>'
```

## How this service works

108 production APIs behind HTTP 402 micropayments. 72 LLMs, Kling V3 and Hailuo video generation, image generation, code execution, travel search, web scraping, TTS, and transaction simulation. Pay with USDC on Base, USDm on MegaETH, or USDC on Solana.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "bodyType",
    "body",
    "method"
   ],
   "properties": {
    "body": {
     "type": "object",
     "anyOf": [
      {
       "required": [
        "audio_url"
       ]
      },
      {
       "required": [
        "audio_base64"
       ]
      }
     ],
     "properties": {
      "audio_url": {
       "type": "string",
       "example": "https://example.com/audio.mp3",
       "description": "URL of audio file to transcribe (provide audio_url OR audio_base64, not both)"
      },
      "audio_base64": {
       "type": "string",
       "example": "data:audio/mp3;base64,SGVsbG8=",
       "description": "Base64-encoded audio data with MIME type prefix (provide audio_url OR audio_base64, not both)"
      },
      "audio_mimetype": {
       "type": "string",
       "example": "audio/mp3",
       "description": "MIME type when using audio_base64 (e.g. audio/mp3, audio/wav)"
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-transcribe-3dd2487e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402engine.app](https://www.zero.xyz/host/x402engine.app/llms.txt)