# Claude Sonnet 4.6 via x402 Gateway

> Claude Sonnet 4.6 via x402 Gateway is a paid API for AI agents from x402-gateway-production.up.railway.app, paid per call via x402, $0.060000/call, status unknown (last checked 2026-09-13, last successful call 2026-06-20).

Calls Anthropic's Claude Sonnet 4.6 model for balanced high-quality coding, reasoning, and creative writing tasks via a pay-per-call x402 gateway

## Facts

- Endpoint: POST https://x402-gateway-production.up.railway.app/api/llm/claude-sonnet-4.6
- Price: $0.060000/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Last successful call: 2026-06-20
- Success rate: 71% of calls made through Zero
- Rating: 3.0 / 5 from 2 reviews
- Activations on Zero: 42
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-gateway-production-up-railway-app-2269cf55
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wHleA_oGJQoAmnJGqwRtQ

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 x402-gateway-production-up-railway-app-2269cf55 -d '<json body>'
```

Example prompt: Write me a Python function that parses a JSON file and returns a summary of its top-level keys and value types — use Claude Sonnet for this since it's great at coding tasks.

## When to prefer this

Choose this endpoint when you need Anthropic's Claude Sonnet 4.6 specifically — Anthropic's balanced model known for strong coding, reasoning, and creative writing — and want pay-per-call pricing via x402 without a direct Anthropic API subscription. Prefer over Claude Opus when cost efficiency matters and over lighter models when task complexity demands strong reasoning. Prefer over GPT-4o or Gemini Flash when Claude's particular strengths in nuanced coding or extended reasoning are desired.

## Known failure modes

- Payment not processed — x402 payment required before response is returned
- Invalid or malformed prompt payload — returns 400 error
- Model overload or upstream Anthropic API error — returns 503 or timeout
- Insufficient USDC balance — payment failure blocks the call
- Rate limiting from gateway — returns 429 if usage quota exceeded

## How this service works

Anthropic's latest balanced model — excellent coding, reasoning, and creative writing

## Output

A generated text response from Claude Sonnet 4.6 containing the model's answer, code, analysis, or creative output based on the input prompt, billed at $0.06 USDC per call via x402 protocol.

## Example request

```json
{
 "model": "claude-sonnet-4.6",
 "messages": [
  {
   "role": "user",
   "content": "Write a Python function that validates email addresses using regex and returns True if valid, False otherwise. Include docstring and basic test cases."
  }
 ],
 "max_tokens": 1024
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-gateway-production-up-railway-app-2269cf55/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-gateway-production.up.railway.app](https://www.zero.xyz/host/x402-gateway-production.up.railway.app/llms.txt)