# QuantaFlow x402 Gateway — AssemblyAI Proxy

> QuantaFlow x402 Gateway — AssemblyAI Proxy is a paid API for AI agents from quanta-roan.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).

Proxies requests to AssemblyAI's speech-to-text and audio intelligence API via the x402 micropayment protocol, charging $0.01 USDC per call.

## Facts

- Endpoint: POST https://quanta-roan.vercel.app/api/service/assemblyai?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quantaflow-x402-gateway-assemblyai-proxy-2c16d3da
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_34zQQYzdzTFw9RIg_TYbf

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 quantaflow-x402-gateway-assemblyai-proxy-2c16d3da -d '<json body>'
```

Example prompt: Transcribe this audio file for me — the URL is https://example.com/meeting.mp3 — using the AssemblyAI proxy and pay the $0.01 USDC fee per call.

## When to prefer this

Choose this endpoint when you need pay-per-use access to AssemblyAI without managing an AssemblyAI subscription or API key, and when your agent supports the x402 micropayment protocol for automatic USDC billing at $0.01 per call. Ideal for low-volume or sporadic transcription needs where a subscription is wasteful.

## Known failure modes

- Payment failure: insufficient USDC balance causes x402 payment rejection before the request is forwarded
- Invalid path: malformed or unsupported AssemblyAI API path returns an upstream 404
- Malformed body: invalid JSON in the body field causes upstream API errors
- Upstream timeout: AssemblyAI processing delays may cause gateway timeouts for long audio
- Rate limiting: AssemblyAI upstream rate limits may be hit if many concurrent calls are made

## How this service works

Every request, a quantum of value. x402 protocol-based payment endpoint for web3/DeFi tools.

## Output

The raw upstream AssemblyAI API response body is passed through, including transcription text, confidence scores, speaker labels, sentiment results, or job status depending on the path called. The content type mirrors the upstream response.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "body": {
   "type": "string",
   "description": "Optional JSON body forwarded to POST requests."
  },
  "path": {
   "type": "string",
   "description": "Path below the selected upstream origin."
  },
  "query": {
   "type": "object"
  },
  "method": {
   "enum": [
    "GET",
    "POST"
   ],
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "description": "The upstream response body and content type are passed through after successful payment."
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quantaflow-x402-gateway-assemblyai-proxy-2c16d3da/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from quanta-roan.vercel.app](https://www.zero.xyz/host/quanta-roan.vercel.app/llms.txt)