# QuantaFlow x402 API Gateway – Stability Endpoint

> QuantaFlow x402 API Gateway – Stability Endpoint is a paid API for AI agents from quanta-roan.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-16).

Proxies requests to a stability-related upstream service (likely Stability AI image generation) via the x402 micropayment protocol, charging $0.01 USDC per call.

## Facts

- Endpoint: POST https://quanta-roan.vercel.app/api/service/stability?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quantaflow-x402-api-gateway-stability-endpoint-395bf97d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5SYjiTiMzCovNnDwYNmBc

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-api-gateway-stability-endpoint-395bf97d -d '<json body>'
```

Example prompt: Generate an image of a sunset over the ocean using Stability AI — route the request through the QuantaFlow gateway and pay the $0.01 USDC fee automatically, sending the prompt as the JSON body to the stability path.

## When to prefer this

Choose this endpoint when you need pay-per-call access to Stability AI (or a stability-related service) without committing to a traditional subscription or API key, and when your agent operates in a web3/crypto context where USDC micropayments via the x402 protocol are preferred. Ideal for autonomous agents that need to self-fund API calls using on-chain balances.

## Known failure modes

- Insufficient USDC balance causes payment failure and request rejection
- Invalid or malformed JSON body string causes upstream error
- Upstream Stability AI service unavailable or rate-limited returns passthrough error
- Incorrect path parameter results in 404 from upstream
- x402 payment protocol negotiation failure blocks request entirely
- Vercel cold start may add latency on first request

## How this service works

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

## Output

The raw upstream response body from Stability AI (or whichever stability service is upstream), passed through transparently along with its content type, after the x402 micropayment of $0.01 USDC has been successfully processed.

## 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-api-gateway-stability-endpoint-395bf97d/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)